Tesis sobre el tema "Spectrophotometer analysi"
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Wheatley, Robert Alan. "Aldehydic lipid peroxidation products : flow analysis using spectrophotometry and chemiluminescence". Thesis, University of Hull, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363331.
Texto completoWolf, Katharine. "Flow injection analysis with photodiode array detection". Thesis, University of Hull, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278427.
Texto completoSooväli, Lilli. "Spectrophotometric measurements and their uncertainty in chemical analysis and dissociation constant measurements /". Online version, 2006. http://dspace.utlib.ee/dspace/bitstream/10062/627/5/soovalililli.pdf.
Texto completoDe, Bock Veerle. "Analysis and interpretation of Aerosol Optical Depth values retrieved from a Brewer spectrophotometer at Uccle, Belgium". Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/277633.
Texto completoDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Rakbamrung, Nawasit. "Determination of some inorganic ions, with or without preconcentration, by flow injection analysis or ion chromatography". Thesis, Liverpool John Moores University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288214.
Texto completoDowds, Eileen. "Automated Data Acquisition for Analysis of Fly Ash by Graphite Furnace Atomic Absorption Spectrophotometry". W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539625520.
Texto completoPhiri, Mohau Justice. "On-line monitoring of base metals solutions in flotation using diffuse reflectance spectrophotometry". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5173.
Texto completoThesis submitted in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE IN ENGINEERING (MINERAL PROCESSING) in the Department of Processing Engineering at the University of Stellenbosch
ENGLISH ABSTRACT: This work evaluates the use of inverse least squares (ILS) and classical least squares (CLS) models for calibration of a diffuse reflectance spectrophotometer for on-line monitoring of the aqueous phase in a flotation cells. Both models use a Beer's law for the quantification of the metals. The formulated statistical models are compared to a proprietary Blue Cube model in terms of prediction ability to determine the potential applicability of the models. A diffuse reflectance spectrophotometry was used for simultaneous analysis of copper (Cu), cobalt (Co) and zinc (Zn) in the solutions. The laboratory set-up of Blue Cube instrument was used for the experimental analysis. The concentrations and matrix compositions of the samples are simulated according to Skorpion zinc mine plant conditions. The calibration samples were prepared using a simplex-centroid mixture design with the triplicates of the centroid run. The unknown or test samples were prepared randomly within the same concentration of the calibration samples. The effects of temperature and nickel concentration on absorption of the metals were evaluated in the following range, 20 - 80 °C and 125 - 400 ppm, respectively. The statistical models (ILS and CLS) were calibrated from visible and near infrared (VNIR) spectra data of the calibration samples. A modified Beer's method was used as a preprocessing technique to convert the raw data into absorbance values. The manual wavelength selection procedure was used to select the wavelengths to be used in both models. The quality of the models was evaluated based on Rª and % root mean squared error (RMSE) values with 0.90 and 10% used as the guideline for the respective statistical parameters. Both ILS and CLS models showed good results for all three metals (Cu, Co and Zn) during their calibration steps. It was further shown that both models give worse predictions for Zn as compared to other metals due to its low relative intensity in the mixture. The derivative orders of absorbance spectra that were used to enhance the prediction results of Zn had no positive effect but they rather lowered accuracy of predictions. An increase in temperature was found to increase the intensities of the absorption spectra of all the metals while an increase in nickel concentration decreases the prediction ability of model. The developed statistical models were compared to a Blue Cube model in terms of prediction ability using analysis of variance (ANOVA) test. The ANOVA results revealed that there is no statistical difference between the developed models and Blue Cube model since the F-values for all the metals were below the critical F-value. Furthermore, the partial least squares (PLS) model shows an increased accuracy results for prediction of zinc metal as compared to both the ILS and CLS models. Finally, good comparisons of the statistical models results with atomic absorption spectroscopy (AAS) analyses were establish for the unknown samples. The study demonstrates that chemometric models (ILS and CLS) developed here can be used for quantification of several metals in real hydrometallurgical solutions as samples were simulated according to a plant conditions. However, in order to have confidence in the results of the models, a factorial-mixture design must be used to study the effect of temperature and nickel concentration. Moreover the models must be further tested and validated on the real samples from a plant.
AFRIKAANSE OPSOMMING: Hierdie werkstuk evalueer die gebruik van inverse kleinste kwadraatmetodes (IKK) en klassieke kleinste kwadraatmetodes (KKK) vir die kalibrasie van 'n diffuse reflektansiespektrofotometer vir die aanlyn monitering van die waterige fase in flottasieselle. Beer se wet word vir die kwantifisering van metale vir albei modelle gebruik. Die omskrewe data-gebaseerde modelle is op grond van voorspellingsvermoë vergelyk met'n. Blue Cube model, sodat die moontlike toepaslikheid van hierdie modelle bepaal kan word. 'n Diffuse reflectantie spektrofotometrie is ingespan vir die gelyktydige analise van koper (Cu), kobalt (Co) en sink (Zn) in oplossing. Eksperimentele analises is met behulp van 'n laboratoriumopstelling met 'n Blue Cube instrument uitgevoer. Die konsentrasies en matriks-samestellings van monsters is gesimuleer om Skorpion sinkmyn aanlegkondisies na te boots. Kalibrasie monsters is voorberei volgens . simpleks-sentroïed mengselontwerp met drievoudige sentroïede lopies. Onbekende (toets) monsters is ewekansig voorberei binne dieselfde konsentrasie spesifikasies as die kalibrasie monsters. Die invloed van temperatuur en nikkelkonsenstrasie op die absorpsie van die metale is in die bestek van 20 - 80 °C en 125 - 400 dpm, onderskeidelik, bepaal. Die data-gebaseerde modelle (IKK en KKK) is met sigbare en naby infrarooi (SNIR) spektra data van die kalibrasie monsters gekalibreer. 'n Gewysigde Beer metode is vir data voorbereiding benut om rou data na absorbansie waardes om te skakel. Die handgolflengte-seleksieprosedure is vir beide modelle gebruik om die golflengtes te kies. Die kwaliteit van die modelle is op grond van Rª en % wortel gemiddelde kwadratiese fout (WGKF) geevalueer, met waardes van 0.90 en 10% (onderskeidelik) as riglyne vir hierdie statistiese parameters. Beide IKK en KKK modelle het vir hul kalibrasie stappe vir al drie metale (Cu, Co en Zn) goeie resultate getoon. Dit is verder getoon dat albei modelle die slegste voorspellings lewer vir Zn (vergeleke met die ander metale) as gevolg van Zn se lae relatiewe intensiteit in die mengsel. Afgeleide ordes van absorbansie spektra is gebruik om die Zn voorspellings te versterk, maar het geen positiewe effek gehad nie; inteendeel, voorspellingakkuraatheid is verlaag. ʼn Verhoging in temperatuur het die intensiteite van die absorpsie spektra van alle metale verhoog, terwyl ʼn verhoging in nikkelkonsentrasie die voorspellingakkuraatheid van die modelle verlaag het. Die ontwikkelde data-gebaseerde modelle is met ʼn Blue Cube model vergelyk in terme van voorspellingsvermoë met behulp van variansie-analise (ANOVA). Die ANOVA resultate toon dat daar geen statistiese verskil tussen die ontwikkelde modelle en die Blue Cube model is nie, aangesien die F-waardes vir al die metale onder die kritiese F-waarde is. Die gedeeltelike kleinste kwadraatmodel (GKK) toon verder verhoogde voorspellingakkuraat-heid vir sinkmetaal tenoor beide die IKK en KKK modelle. Ten slotte, goeie ooreenstemming van die data-gebaseerde modelresultate met atoomabsorpsie spektroskopie (AAS) analise is vir die onbekende monsters gevind. Hierdie werkstuk toon dat die chemometriese modelle (IKK en KKK) wat hier ontwikkel is, gebruik kan word vir die kwantifisering van verskeie metale in werklike hidrometallurgiese oplossings, aangesien monsters gesimuleer is volgens aanlegkondisies. Om egter verdere vertroue te hê in die modelresultate, sal ʼn faktoriaal-mengselontwerp toegepas moet word om die effek van temperatuur en nikkelkonsentrasie te ondersoek. Voorts moet die modelle verder getoets en gevalideer word op werklike monsters van ʼn aanleg.
Nilsson, Karolina. "Spectrophotometric measurement automatization for the analysis of enzymatic processes". Thesis, Uppsala University, Signals and Systems Group, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-125723.
Texto completoThis thesis work consisted of the development of a virtual instrument that automates enzyme activity measurements and spectrum measurements with the spectrophotometer UVmini-1240. The purpose was to expand the functionality of the instrument, to eliminate the human error and to decrease the amount of time spent on measurements. A PC was connected to the UVmini-1240 via a RS-232C interface and the cell position and temperature was regulated with a CPS-240A controller. The new interface allows all the parameters to be set in the same place. It allows a visualization of the continuous monitoring of the sample absorbance and the option to save the data for post-processing. Also a module for measuring the spectrum of a sample in the wavelength range of 190 nm to 1100 nm is included. The graphical programming language LabView was used to develop the virtual instrument. This thesis work also contained measurement series of the catalase enzyme activity. These were carried out to determine the best storage temperature for the catalase solution and to determine the optimal surrounding temperature for the highest activity in the catalase solution. The conclusions were that the activity does not change considerably the first week of storage, not matter the temperature, and that the activity goes down when the surrounding temperature reaches above 30° C. These measurements were part of a bigger project to develop an ultrasonic method for measuring enzyme activity at the Institute of Acoustics at C.S.I.C in Madrid.
Elkhazin, Mohamed M. A. "Analysis of coronal discoloration from commonly used obturation materials". Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8814_1256029448.
Texto completoThe objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.
Avramidis, Stefanos. "Simulation and parameter estimation of spectrophotometric instruments ". Thesis, KTH, Numerical Analysis and Computer Science, NADA, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12292.
Texto completoThe paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm.The paper and the graphics industries use two instruments with different optical geometry (d/0 and 45/0) to measure the quality of paper prints. The instruments have been reported to yield incompatible measurements and even rank samples differently in some cases, causing communication problems between these sectors of industry.A preliminary investigation concluded that the inter-instrument difference could be significantly influenced by external factors (background, calibration, heterogeneity of the medium). A simple methodology for eliminating these external factors and thereby minimizing the instrument differences has been derived. The measurements showed that, when the external factors are eliminated, and there is no fluorescence or gloss influence, the inter-instrument difference becomes small, depends on the instrument geometry, and varies systematically with the scattering, absorption, and transmittance properties of the sample.A detailed description of the impact of the geometry on the results has been presented regarding a large sample range. Simulations with the radiative transfer model DORT2002 showed that the instruments measurements follow the physical radiative transfer model except in cases of samples with extreme properties. The conclusion is that the physical explanation of the geometrical inter-instrument differences is based on the different degree of light permeation from the two geometries, which eventually results in a different degree of influence from near-surface bulk scattering. It was also shown that the d/0 instrument fulfils the assumptions of a diffuse field of reflected light from the medium only for samples that resemble the perfect diffuser but it yields an anisotropic field of reflected light when there is significant absorption or transmittance. In the latter case, the 45/0 proves to be less anisotropic than the d/0.In the process, the computational performance of the DORT2002 has been significantly improved. After the modification of the DORT2002 in order to include the 45/0 geometry, the Gauss-Newton optimization algorithm for the solution of the inverse problem was qualified as the most appropriate one, after testing different optimization methods for performance, stability and accuracy. Finally, a new homotopic initial-value algorithm for routine tasks (spectral calculations) was introduced, which resulted in a further three-fold speedup of the whole algorithm.
QC 20100707
PaperOpt, Paper Optics and Colour
Ansell, Seth. "A study of ellipsoidal variance as a function of mean CIELAB values in a textile data set /". Online version of thesis, 1995. http://hdl.handle.net/1850/12232.
Texto completoBurger, James. "Hyperspectral NIR image analysis : data exploration, correction, and regression /". Umeå : Unit of Biomass Technology and Chemistry, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200660.pdf.
Texto completoPalm, Elise. "Comparison of Mineral- and Protein Content between Conventional, Organic and Biodynamic Swedish Winter Wheat with Atomic Absorption Spectrophotometry and Elemental Combustion Analysis". Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-2429.
Texto completo
Correlation between production method and mineral-, cadmium- and protein content were sought for Swedish winter wheat. The wheat was grown according to conventional, organic or biodynamic principles. The minerals; iron, zinc, magnesium, copper and the heavy metal cadmium were analyzed with atomic absorption spectroscopy. Protein was analyzed with elemental combustion analysis. All together, 17 samples were analyzed; nine from the still ongoing Bollerup field trial in Skåne and eight from four different farm pairs in the midst of Sweden.
The Bollerup field trials showed that organic wheat had a higher concentration of iron than conventional. Both organic and biodynamic wheat had a higher concentration of zinc than conventional. Magnesium concentration was higher in biodynamic wheat than in conventional grown wheat. Differences between production methods were in the range of 7.5 and 17%.
No unmistakable connections were found between any of the parameters and production method for the farm pairs. However, a tendency for more minerals in organic/biodynamic wheat was seen for all minerals but iron.
Due to unclean equipment, analyzing of cadmium contents could not be completed.
Consiglieri, Vladi Olga. "Doseamento da vitamina B6 por espectrofotometria derivada no ultravioleta". Universidade de São Paulo, 1992. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-10072008-170738/.
Texto completoA rapid and selecrive method for rhe dererminarion of pyridoxine in pharmaceuticals has been described. The procedure has been developed using direct UV first-derivative spectrofotometry in solid and liquid preparations (tablets, oral solution and injection). Spectral inrerferences from formulation excipienrs and other drugs in simple UV spectrophotometric methods have been eliminated by the application of the proposed method. Calibration curves have been made and the correlation coefficienr for. the first-order derivative was 0,99997. Standard deviation, coefficient of variation and confidence interval were calculated. The method was applied in the analysis of commercial and simulated samples. The results when compared with those obtained by using the USP 22nd. ed. official method shows clear advanrages related to accuracy, precision and practical application.
Tozo, Greici Cristiani Gomes [UNESP]. "Análise qualitativa e quantitativa de cefoxitina sódica em injetáveis: desenvolvimento e validação de métodos analíticos e estudo de estabilidade". Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/101326.
Texto completoUniversidade Estadual Paulista (UNESP)
A cefoxitina sódica (CAS 33564-30-6), antimicrobiano cefalosporínico, apresenta espectro de atividade contra microrganismos Gram-negativos mais amplo que as cefalosporinas mais antigas. Também é eficaz contra Proteus e Serratia indol-positivos, mostrando alta resistência à hidrólise por b-lactamases. Indicada no tratamento de peritonites e outras infecções intra-abdominais e intrapélvicas; sinusites, infecções ginecológicas, septicemias; endocardites; infecções do trato urinário, gonorréia não complicada, infecções do trato respiratório, ossos, articulações e pele. Apesar de este fármaco ser altamente estudado e pesquisado no que concerne à atividade antimicrobiana, farmacocinética e farmacodinâmica, há poucos estudos na literatura em relação ao desenvolvimento de metodologia analítica para esta cefalosporina. Desta forma, pesquisas envolvendo métodos analíticos são de fundamental importância e altamente relevantes para otimizar sua análise na indústria farmacêutica e farmpacia magistral de modo a garantir a qualidade do produto já comercializado. A proposta deste projeto foi desenvolver metodologias de análise para a cefoxitina sódica, fármaco comercializado no mercado médico-farmacêutico brasileiro. Foram desenvolvidos e validados métodos por CLAE com detector UV a 235 nm, com acetonitrila: água: ácido acético 5 M (22 : 78 : 1) como fase móvel e faixa de concentração de 20,0 à 30,0 μg/mL, tempo de retenção de 7,5 minutos. O coeficiente de correlação obtido foi de 0,9995 e a equação da reta y = 335,67x + 2391,9. O teste recuperação média obtido foi de 100,50%, com desvio padrão de 1,70%. O teor médio...
Sodium cefatoxin (CAS 33564-30-6), a cephalosporinic antibiotic, has a wider spectrum of activity against Gram-negative microrganisms than older cephalosporin. It is also efficient against the indol-positive Proteus and Serratia and has a high resistance to b- lactamases hydrolysis. Sodium cefatoxin is recommended for the treatment of peritonitis and other intra-abdominal and intra-pelvic infections; sinusitis, gynecological infections, septicemy, endocarditis; urinary tract infections, non-complicated gonorrhea, respiratory tract infections, bones, articulations and skin. Although this drug has been strongly studied and many researches have been developed about its antibiotics activity, pharmacokinetics and pharmacodynamics, there are few studies in the literature about the development of analytical methodology to this cephalosporin. Researches dealing with analytical methods are extremely important and highly relevant to optimize its analysis at the pharmaceutical industry and manipulation pharmacy, guaranteeing quality of the commercialized product. This project proposes the development of methodologies for analysis of sodium cefatoxin, a commercialized drug at the medical-pharmaceutical Brazilian market. Methods for CLAE with UV detector at 235nm were developed and validated with acetonitrile: water: acetic acid 5M (22: 78:1) as mobile phase and concentration range of 20.0 to 30.0 μg/mL, detention time of 7.5 minutes. The correlation coefficient obtained was 0.9995 and the line equation y = 335.67x + 2391.9. The medium recovery test was 100.50% with standard deviation of 1.70%. The medium content of sodium cefoxitin determined by CLAE... (Complete abstract click electronic access below)
Meneses, Silvia Regina Pessoa de. "Monitoramento de espécies químicas produzidas durante a fermentação alcoólica utilizando sistemas de análises em fluxo". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-25112009-100121/.
Texto completoFlow injection systems involving gas diffusion were designed for spectrophotometric determination of sulfide and sulfite in fermented sugarcane juices and molasses, aiming at yeast selection relying on their amounts produced during fermentation process. N,N-dimethyl-p-phenylenediamine (DMPD) e malachite green (MG) were used for sulfide and sulfite determinations, respectively. Reaction of sulfide with DMPD was developed in the presence of Fe(III) under acidic conditions, and yielded molybdenum blue (MB), which was monitored at 668 nm. The analytical signal was recorded as a peak with height proportional to the sulfide content in the sample. Reaction of sulfite with MG was developed under alkaline conditions, and caused a MG absorbance lessening monitored at 620 nm. The analytical signal was recorded as an inverted peak proportional to the sulfite concentration. For both determinations, the main involved parameters such as flow rates, reagent concentrations, pH of the reaction media, temperature, sample inserted volume, manifold geometry, as well as the presence of surfactants and concentrated electrolytes were investigated, allowing further system optimization. Due to analyte interactions with the carbonyl groups of some chemical species in the sample, as well as electrostatic attractions of the formed gaseous species by the solid suspended particles, the volatilization step constituted itself in a limiting factor for applying the procedures to in situ analysis. In this context, the need for a previous sample treatment was suggested. The proposed systems are rugged and yield precise results (r.s.d. < 2 %) at a sampling rate of 30 determinations per hour. Linearity of the analytical curves was noted up to 5.0 mg L-1 S-S2- or 25.0 mg L-1 S-SO2, detection limits were estimated as 0.04 mgL-1 S-S2- and 0.7 mg L-1 S-SO2, and the reagent consumptions were 0.6 mg DMPD and 0.002 mg MG per determination. Exploitation of the standard addition method for overcoming matrix effects was suggested
Ashie, Jennifer Bernice. "Study on Methods of Simultaneous Multi-Component Analysis". Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1989.
Texto completo曾志堅 y Chi-kin Tsang. "Analysis and control of organic vapours in air and determination of metals and toxic elements in fish samples by differential pulsevoltammetry and atomic absorption spectrophotometry". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210995.
Texto completoWolf, Aaron B. "Determining Whether Spectrophotometer CIE L*a*b* Color Analysis is an Effective Alternative to Munsell Soil Color Charts for the Study of Burnt Bones: Insights From Analysis of Bab edh-Dhra EB II-III Burnt Bones". Oberlin College Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1305140303.
Texto completoTigabu, Mulualem. "Characterization of forest tree seed quality with near infrared spectroscopy and multivariate analysis /". Umeå : Dept. of Silviculture, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s274.pdf.
Texto completoTsang, Chi-kin. "Analysis and control of organic vapours in air and determination of metals and toxic elements in fish samples by differential pulse voltammetry and atomic absorption spectrophotometry /". [Hong Kong : University of Hong Kong], 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13408914.
Texto completoOliveira, Paulo Cesar Costa de. "Aplicações espectrofotométricas da análise por injeção seqüencial (SIA). 1. Determinação de Cr(VI) por oxidação do alcalóide brucina. 2. Determinação de Fe(II) por complexação com 2,2´-bipiridila". Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-15022019-145443/.
Texto completoSequential injection methodologies were developed for determination of Cr(VI) and Fe(II) in samples of industrial and environmental interest. Cr(VI) was determined by the reaction with the alkaloid brucine, which is oxidized producing an intermediate with short lifetime and strong molar absorptivity between 500 and 550 nm. The optimized methodology was applied in the determination of Cr in certified stainless-steel samples and metallurgical industrial effluents. This was further exploited in the development of sequential injection procedures to perform in-line dilution and in-line standard addition, ln addition to the construction and application of a thin layer vertical flow cell for spectrophotometric measurements was performed. A sequential injection methodology for determination of Fe(II) was developed based on the reaction with 2,2\' -bipyridyl. This reaction produces a very stable pink complex with strong absorptivity peak at 523 nm. The methodology was tested and applied in Fe(II) determination in anti anemic pharmaceutical formulations and in the speciation Fe(II)/Fe(III) speciation in acetic extracts from river sediments.
Fisher, Suzanne, N. S. Nicholas y Phillip R. Scheuerman. "Dendrochemical Analysis of Lead and Calcium in Southern Appalachian American Beech". Digital Commons @ East Tennessee State University, 2002. https://dc.etsu.edu/etsu-works/2872.
Texto completoGuimarães, Marcelo. "Desenvolvimento de nanopartículas de poli (n-butil-cianoacrilato) com zidovudina revestidas por ácido hialurônico para veiculação em gel de uso transdérmico". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-16032016-101157/.
Texto completoZidovudine (AZT) is still the most widely used drug in the treatment of AIDS, alone or in combination with other antiretroviral drugs, however it is indicated in high doses and has adverse effects that compromise patient compliance to treatment. Thus, a new zidovudine delivery system made of poly (n-butyl-cyanoacrylate) nanoparticles coated with hyaluronic acid (HA) was developed and characterized in order to extend the drug release and reduce its toxicity. The nanoparticles have been widely studied as drug carriers once they remain in circulation for a longer period and, consequently, release the drug gradually. For the polymerization, and, therefore synthesis of nanoparticles, n-butyl-cyanoacrylate and Dextran® were added to 0.1 M HCl (pH 2.5) and stirred at 800 rpm for 1 hour. AZT was added and the reaction was neutralized by the addition of 0.1 M NaOH after 3 more hours of agitation. After filtration the particles were coated by addition of an aqueous dispersion of hyaluronic acid (HA) at low revs. The mean hydrodynamic diameter of non-coated nanoparticles was 152.3 nm with an average polydispersity index of 0.055. The average zeta potential of these particles was -0.678 mV. The average hydrodynamic diameter of the coated nanoparticles was 196.9 nm, presenting an average polydispersity index of 0.440. The average zeta potential of these particles was -25.6 mV. The resulting values of these tests are indicative not only of the stability of the obtained nanoparticles but also the good reactivity of the monomers of cyanoacrylates. Moreover, the results can confirm the occurrence of coating. Thus, the efficiency of the coating process of the nanoparticles can be demonstrated by the results of the analysis of differential scanning calorimetry (DSC) and the results of the absorption spectroscopy in the infrared region. In order to quantify the drug associated with the nanoparticles, a method employing derivative spectrophotometry (ED1) UV applying the zero-crossing technique was developed and validated. This method allowed the elimination of interference of excipientes, allowing the quantification of AZT nanoparticles in suspension with adequate accuracy and precision. The percentage of the drug associated with the obtained nanostructures by the method was 64%. The nanoparticles were incorporated into a Carbopol® 940 gel formulation, which was stable after being subjected to different storage conditions, with incidence of light and temperature variation.
Tozo, Greici Cristiani Gomes. "Análise qualitativa e quantitativa de cefoxitina sódica em injetáveis : desenvolvimento e validação de métodos analíticos e estudo de estabilidade /". Araraquara : [s.n.], 2007. http://hdl.handle.net/11449/101326.
Texto completoBanca: Marcos Antonio Segatto
Banca: Cristiane Masetto de Gaitani
Banca: Maria Virgínia Costa Scarpa
Banca: Thereza Christina Vessoni Penna
Resumo: A cefoxitina sódica (CAS 33564-30-6), antimicrobiano cefalosporínico, apresenta espectro de atividade contra microrganismos Gram-negativos mais amplo que as cefalosporinas mais antigas. Também é eficaz contra Proteus e Serratia indol-positivos, mostrando alta resistência à hidrólise por b-lactamases. Indicada no tratamento de peritonites e outras infecções intra-abdominais e intrapélvicas; sinusites, infecções ginecológicas, septicemias; endocardites; infecções do trato urinário, gonorréia não complicada, infecções do trato respiratório, ossos, articulações e pele. Apesar de este fármaco ser altamente estudado e pesquisado no que concerne à atividade antimicrobiana, farmacocinética e farmacodinâmica, há poucos estudos na literatura em relação ao desenvolvimento de metodologia analítica para esta cefalosporina. Desta forma, pesquisas envolvendo métodos analíticos são de fundamental importância e altamente relevantes para otimizar sua análise na indústria farmacêutica e farmpacia magistral de modo a garantir a qualidade do produto já comercializado. A proposta deste projeto foi desenvolver metodologias de análise para a cefoxitina sódica, fármaco comercializado no mercado médico-farmacêutico brasileiro. Foram desenvolvidos e validados métodos por CLAE com detector UV a 235 nm, com acetonitrila: água: ácido acético 5 M (22 : 78 : 1) como fase móvel e faixa de concentração de 20,0 à 30,0 μg/mL, tempo de retenção de 7,5 minutos. O coeficiente de correlação obtido foi de 0,9995 e a equação da reta y = 335,67x + 2391,9. O teste recuperação média obtido foi de 100,50%, com desvio padrão de 1,70%. O teor médio... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Sodium cefatoxin (CAS 33564-30-6), a cephalosporinic antibiotic, has a wider spectrum of activity against Gram-negative microrganisms than older cephalosporin. It is also efficient against the indol-positive Proteus and Serratia and has a high resistance to b- lactamases hydrolysis. Sodium cefatoxin is recommended for the treatment of peritonitis and other intra-abdominal and intra-pelvic infections; sinusitis, gynecological infections, septicemy, endocarditis; urinary tract infections, non-complicated gonorrhea, respiratory tract infections, bones, articulations and skin. Although this drug has been strongly studied and many researches have been developed about its antibiotics activity, pharmacokinetics and pharmacodynamics, there are few studies in the literature about the development of analytical methodology to this cephalosporin. Researches dealing with analytical methods are extremely important and highly relevant to optimize its analysis at the pharmaceutical industry and manipulation pharmacy, guaranteeing quality of the commercialized product. This project proposes the development of methodologies for analysis of sodium cefatoxin, a commercialized drug at the medical-pharmaceutical Brazilian market. Methods for CLAE with UV detector at 235nm were developed and validated with acetonitrile: water: acetic acid 5M (22: 78:1) as mobile phase and concentration range of 20.0 to 30.0 μg/mL, detention time of 7.5 minutes. The correlation coefficient obtained was 0.9995 and the line equation y = 335.67x + 2391.9. The medium recovery test was 100.50% with standard deviation of 1.70%. The medium content of sodium cefoxitin determined by CLAE... (Complete abstract click electronic access below)
Doutor
Grassi, Viviane. "Polímeros molecularmente impressos (MIPs) como extratores em fase sólida em sistemas de análises em fluxo". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-16092008-142648/.
Texto completoMolecularly imprinted polymers (MIPs) are promising as material to be used in solid phase extractions due to their high selectivity. MIPs selectivity is directly related to the recognition of a molecule of interest, which was previously employed as template in the synthesis process. The main favorable characteristics of MIPs are the easy preparation, low cost, possibility of synthesis in adverse environments, and chemical resistance in the presence of acids, bases, metal ions, organic solvents as well as the physical resistance to high temperatures and pressures. In the present work, flow systems with molecularly imprinted polymers as in-line solid phase extractors were designed, and their characteristics and efficiencies were assessed in relation to the spectrophotometric determinations of the catechol, ascorbic acid and atrazine in environmental, pharmacological and food samples. Moreover, the feasibility of chiral separation was investigated in relation to D and L-ascorbic acid. Potentialities and limitations of implementing MIPs in flow analysis were highlighted
Herka, Milan. "Monitoring obsahu fosforu a dusíku v odpadních vodách". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217032.
Texto completoLavorante, André Fernando. ""Desenvolvimento de instrumentação e procedimentos analíticos automáticos para a determinação espectrofotométrica de tensoativos em águas"". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-03042006-184414/.
Texto completo"In this work, development of the instrumentation and automatic analytical procedures for spectrophotometric determination of surfactants in waters employing the multicommutation concept were proposed. Aiming to system miniaturization, reduction of reagents consumption and effluents generation, solenoids micro-pump and solenoids pinch valves were used for the fluids propulsion and for solutions management, respectively. These devices were controlled by a microcomputer equipped with an electronic interface based on the integrate circuit ULN2803A that was coupled to the printer output. As system detection was employed an spectrophotometer model HP8452A, a multichannel spectrophotometer with CCD array linear arrangement of photodetectors and a homemade LED based photometer comprising two LEDs (blue and red) as radiation source and a photodiode (IPL10530DAL) as detector. In this case, the data acquisition was accomplished with a digital multimeter with serial out put RS232 employing a software wrote in VISUAL BASIC 3.0. The software comprised also routines to control the analysis module. Firstly, instrumentation and analytical procedures for independent determination of anionic and cationic surfactants in waters were developed. The same flow system comprised of four solenoid micro-pumps and it was employed for both surfactants. The procedure proposed for the determination of anionic surfactant was based on the substitution reaction of orange methyl (MO) by anionic surfactant (sodium dodecylbenzene sulfonate - DBS) to form an ion-pair with the cetyl pyridine (CPC) at pH 5.0. The proposed instrumentation allowed the achievement of a lineal response range between 1.4 x 10-6 mol L-1 and 1.4 x 10-5 mol L-1 (0.5 5.0 mg L-1) (R = 0.997, n = 7), a detection limit of 9.8 x 10-8 mol L-1 (0.034 mg L-1), a relative standard deviation of 0.8% (n = 11) for a reference solution containing 5.7 x 10-6 mol L-1 (2.0 mg L-1) DBS and sampling throughput of 60 determinations per hour. Results obtained applying the proposed procedure for domestic and industrial effluent samples were compared with those obtained using reference method and no significant differences at the 95 % confidence level was observed. For the determination of cationic surfactant in waters the procedure was developed based on the ternary complex formation between CPC, Fe (III) and chromazurol S at pH 4.5. The proposed system comprised a flow cell device with 40 mm optical path-length presented the following features: a linear response range between 0.1 x 10-5 mol L-1 e 3.0 x 10-5 mol L-1 (0.34 10.2 mg L-1) (R = 0.999, n = 9); a detection limit of 1.0 x 10-7 mol L-1 (0.035 mg L-1); a relative standard deviation of 0.6 % (n = 11) for a reference solution containing 1.0 x 10-5 mol L-1 (3.4 mg L-1) CPC; and a sampling throughput of 72 determinations per hour. The procedure was applied to samples waters collected in the Piracicaba River. Using standard addition test recoveries between 91 % and 106 % were observed. The flow network for the sequential determination of anionic and cationic surfactants comprised two solenoid micro-pumps and six solenoid pinch valves. Employing the system proposed for the determination of anionic surfactants the folowing analytical characteristics: linear response range between 0.1 x 10-5 mol L-1 e 3.0 x 10-5 mol L-1 (0.35 10.5 mg L-1) (R = 0.9992, n = 7); a detection limit of 1.6 x 10-7 mol L-1 (0.056 mg L-1); a relative standard deviation of 0.6 % (n = 11) for a reference solution containing 1.0 x 10-5 mol L-1 (3.5 mg L-1) DBS were observed. For cationic surfactants a linear response range between 0.1 x 10-5 mol L-1 e 3.0 x 10?5 mol L-1 (0.34 - 10.2 mg L-1) (R = 0.9992, n = 7), a detection limit of 1.4 x 10-7 mol L-1 (0.05 mg L-1), a relative standard deviation of 0.5 % (n = 11) for a reference solution containing 1.0 x 10-5 mol L-1 (3.4 mg L-1) CPC were observed. In both cases, the reagents and sample consumption were 400 mL and 200 mL, respectively. The sampling throughput of 60 determinations per hour was achieved for both surfactants. The system was applied to waters samples from the Corumbataí River. The results obtained using the standard addition test presented recoveries between 91 % and 105 %. Applying t-test between the results obtained by the proposed procedures and those obtained using reference procedures showed that for anionic and cationic surfactants, the results were concordant at 95% confidence level."
Oliveira, Eliézer de. "Determinação espectrofotométrica catalítica de molibdênio e ferro explorando calibração multivariada em um sistema de análises químicas em fluxo". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-02022016-110804/.
Texto completoThe catalytic effects of Mo(VI) and Fe(III) in the oxidation of iodide by hydrogen peroxide were exploited aiming at their simultaneous determination. Differences in reaction rates were achieved by establishing of two distinct reactions zones to modify the reaction kinetics involved. To this end, a flow injection system allowing insertion of two sample aliquots was designed, and sulfuric acid was added to one of the aliquots. A complex sample zone was then established. Each fluid element of this zone was characterized by a given chemical composition, residence time and reaction rate. The main parameters affecting the reaction rate, such as reagent concentrations, analytical path length and total flow rate, among others, were evaluated for improving sensitivity and analyte kinetic discrimination. Influences of sampling loop lengths and distance between initial plugs were studied, and mathematical models were constructed aiming at improved discrimination in prediction of analytes. The models were constructed from the PLS (Partial Least Squares) chemometric tool using data generated by measurements performed on sample zone regions with maximum and minimum local concentrations. The calibration set consisted of Mo(VI) and Fe(III) mixtures in concentration ranges of 6.2 - 50.0 ?g L-1 and 0.5 - 7.0 mg L-1, respectively. The selected model is characterized by good prediction ability prediction, as RMSEP values were estimated as 0.67 ?g L-1 for Mo(VI) and 0.21 mg L-1 for Fe(III), respectively. Recoveries within the 85 - 114% range were obtained for natural waters. The proposed system presents physical stability and favorable characteristics of measurement repeatability (r.s.d.<2%), sampling rate (31 h-1) and reagent consumption (54 mg of KI and 0.30 mg H2O2 per sample)
Wetterlind, Johanna. "Improved farm soil mapping using near infrared reflection spectroscopy". Uppsala : Dept. of Soil and Environment, Swedish University of Agricultural Sciences, 2009. http://epsilon.slu.se/200968.pdf.
Texto completoNilsson, Anders. "Novel Technique for Analysing Volatile Compounds in Indoor Dust : Application of Gas Chromatography – UV Spectrometry to the Study of Building-Related Illness". Doctoral thesis, Linköping : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5199.
Texto completoPrazeres, Kelly Cristina dos. "Monitoramento e avaliação dos riscos causados por diclofenaco em efluentes e água de abastecimento de um município da região metropolitana de São Paulo". Universidade Nove de Julho, 2017. http://bibliotecatede.uninove.br/handle/tede/1711.
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Diclofenac and its metabolites are frequently reported in the literature and have already been detected in surface water from several countries, such as Germany, Sweden, Greece, Taiwan, Switzerland and Spain. Their damage to the environment to human health is causing concern, as they can increase bacterial resistance, feminization of fish and reduction of human sperm production, etc. Thus, this work aimed at monitoring the presence of diclofenac in drinking water and effluent in a city in the Greater São Paulo Region, evaluating the risks of soil contamination, aquatic environments and human health. A questionnaire was developed in order to measure the level of population knowledge about the impacts caused by the irregular disposal of diclofenac. During the application of the questionnaires were collected water supply samples. Samples of sanitary sewage effluents were also collected in the ETEs exit channel of the same city. Analyzes were performed by UV/vis spectrophotometry using potassium permanganate as to oxidize diclofenac in acidic medium. A risk matrix has been developed to verify what danger situation the city is in. The results presented in the tabulation of the questionnaire data showed that 72% of the interviewees practiced incorrect disposal of the drugs (garbage, toilet and sink). And, the analyzes in the samples detected the presence of diclofenac in effluent water (5.0 mg.L-1) and in the supply water (between 2.5 and 3.1 mg.L-1). This may be a consequence of these incorrect discards. In this way, the risk analysis showed that under current conditions the water bodies can lead to catastrophic or serious consequences with very high probability of occurrence of resistant bacteria, death of aquatic species, anticipated hatching of animal eggs, cell mutation and liver inflammation In animals and delayed growth and decreased reproduction due to sperm reduction in humans. Thus, this work was able to identify the presence of diclofenac in samples of water supply and sanitary effluent; Serving as an alert for Public Bodies to make decisions in order to minimize their effects on the environment and the human being.
O diclofenaco e seus metabólitos são relatados com frequência na literatura e já foram detectados em água superficiais de diversos países, como: Alemanha, Suécia, Grécia, Taiwan, Suíça e Espanha. Os seus danos ao meio ambiente a à saúde humana estão causando preocupação, pois podem aumentar a resistência de bactérias, a feminilização de peixes e a redução da produção de esperma humano, etc. Assim, este trabalho objetivou o monitoramento da presença do fármaco diclofenaco em água de abastecimento e efluente em uma cidade da Região da Grande São Paulo, avaliando os riscos de contaminação do solo, de ambientes aquáticos e para a saúde humana. Um questionário foi elaborado de forma a se mensurar o grau de conhecimento de população sobre os impactos causados pelo descarte irregular do diclofenaco. Durante a aplicação dos questionários foram coletadas amostras de água de abastecimento. Coletou-se também, amostras de efluentes de esgoto sanitário, no canal de saída de ETEs da mesma cidade. As análises foram realizadas por espectrofotometria UV/vis usando o permanganato de potássio como para oxidar o diclofenaco em meio ácido. Uma matriz de risco foi elaborada para verificar a que situação de perigo a cidade se encontra. Os resultados apresentados na tabulação dos dados do questionário mostraram que 72% dos entrevistados praticam o descarte incorreto dos fármacos (lixo, vaso sanitário e pia). As análises nas amostras detectaram a presença do diclofenaco em água de efluente (5,0 mg.L-1) e na água de abastecimento (entre 2,5 e 3,1 mg.L-1). O que pode ser uma consequência destes descartes incorretos. Desta forma, a análise de riscos mostrou que nas condições atuais os corpos hídricos podem levar a consequências catastróficas ou graves com probabilidade muito alta de ocorrência de bactéria resistentes, morte de espécies aquáticas, eclosão antecipada de ovos de animais, mutação celular e inflamação de fígado em animais e retardo no crescimento e diminuição da reprodução devida redução de esperma no ser humano. Assim, este trabalho conseguiu identificar a presença do diclofenaco em amostras de água de abastecimento e de efluente sanitário; servindo de alerta para que os Órgãos Públicos tomem decisões de forma a minimizar os seus efeitos ao meio ambiente e ao ser humano.
Dias, Ana Cristi Basile. "\"Sistemas de análises químicas em fluxo explorando multi-impulsão e detecção espectrofotométrica: aplicação a formulações farmacêuticas e a extratos de solos\"". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-01062007-151046/.
Texto completoMulti-pumping flow systems (MP) utilize solenoid pumps as fluid propelling devices, which deliver pulsed flows. This feature was evaluated in relation to the design, operation and performance of the system, to the mixing conditions, and to the dispersion of the introduced solution. The general evaluation of the MP systems involved investigations about precision and accuracy of the pulse volumes, as well as the pump ruggedness. To this end, gravimetric measurements were carried out. Moreover, dispersion was evaluated by exploiting a colored solution and spectrophotometric monitoring. Results were corroborated through analytical applications. Use pumps delivering higher pulse volumes (> 25 l) was limited when the pulsation frequency was > 4.0 Hz. The experimentally measured volumes were in agreement with to the expected values (relative error < 2.0 %). Sample dispersion was lower in relation to that inherent to laminar flow (multi-commuted flow system, MC).Exploitation of pulsed flow led to a enhanced reaction development mainly due to shaking of neighboring fluid elements. This aspect was important in relation to spectrophotometric determination of bromhexine in pharmaceuticals The method was based on electrophylic coupling of bromhexine with 3-methyl-2-benzothiazolinone hydrazone (MBTH), with further oxidation by Ce(IV) under acidic medium. Analytical sensitivity was fair, reagent consumption was low and sampling rate was 300 h-1. These figures of merit were not compared with those inherent to the MC system due to the lack of sensitivity of this system. Another application was the spectrophotometric determination of phosphate in soil extracts relying the molybdenum blue formation. Best analytical results were obtained for < 0.5 Hz pulse frequency, due to the higher available time for interaction among the involved chemical species. The proposed MP system required lower sample volume (48 l) in relation to the MC system (96 l), being characterized by higher sampling rate (MP: 144 h-1; MC: 67 h-1). Analytical results related to soil extracts were in agreement between them and with the reference method. Visualization of a dispersing sample in a pulsed flow became feasible using the laser induced fluorescence technique applied to Rhodamine B, RB. Experiments were performed under high (3.0 Hz) or low (0.5 Hz) pulse frequency, optional insertion of a reactor between the injection point and detection, and vertical or horizontal positioning of the flow-cell. Analyses of the graphs obtained allowed the visualization of the mass re-distribution in function of time. In general, vortex formation at the central portion of the sample zone and a high RB migration in the radial direction, were noted. Concerning axial direction, better sample / carrier stream interactions were observed for lower pulse frequency and insertion of the 60-cm reactor. Vortex establishment led to a punctual and fast mixing, as confirmed by the analytical applications
Micelli, Alexandre Santos. "Avaliação de método espectrofotométrico automatizado para a determinação de cianeto total em amostras de influentes industriais". Niterói, 2018. https://app.uff.br/riuff/handle/1/5751.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
O trabalho apresenta um método analítico simples, rápido e que possibilitou a determinação de cianeto com baixos limites de detecção em amostras de efluentes industriais provenientes de uma refinaria de petróleo. O processo utilizado foi baseado em método proposto por Nagaraja, Kumar, Yathirajan e Prakash (2002). A detecção e determinação de pequenas quantidades de íons cianeto é importante devido à extrema toxicidade desta espécie para a matéria viva. Os baixos limites de concentração de cianeto exigidos pelas entidades de controle ambiental para águas de efluentes industriais, demandam o desenvolvimento de métodos analíticos sensíveis. A medida de cianeto foi realizada após o pré-tratamento da amostra por destilação, conforme recomendado pela APHA (American Public Health Association), possibilitando a liberação do cianeto sob a forma de HCN, o qual foi coletado, processado em sistema FIA (Flow Injection Analysis) e quantificado espectrofotometricamente. Realizou-se a otimização do sistema FIA após várias etapas de estudo envolvendo interpretação e análise dos resultados obtidos quando para diferentes concentrações dos reagentes, temperatura, tamanho das bobinas utilizadas no sistema e concentração da solução padrão em uma das alças de amostragem. O sistema FIA utilizado constou de duas válvulas de amostragem, sendo uma para introdução de volume pré-determinado de solução padrão de cianeto de concentração conhecida e outra para introdução das soluções de calibração ou amostras. Para a obtenção dos resultados, foram construídas curvas analíticas, através da utilização de padrões de cianeto contendo de 0,01 a 0,04 mg.mL–1, as quais foram utilizadas na análise das 6 (seis) amostras de efluentes finais de uma refinaria de petróleo. Os resultados foram validados através da comparação com a metodologia clássica recomendada pela APHA. O método desenvolvido de fácil aplicação e de baixo custo pode ser utilizado com confiança, pois os resultados obtidos com o método padrão foram comparáveis aos encontrados pelo método espectrofotométrico automático proposto. O limite de detecção obtido para cianeto foi de 0,02 μg.mL–1, adequado para a determinação de cianeto em efluentes industriais.
The work shows a simple and fast analytical method, fast capable of determination of cyanide at low detection limits in an oil refinery industrial waste samples. The used process was based on the reaction proposal for Nagaraja, Kumar, Yathirajan e Prakash (2002). The detection and determination of low amounts of cyanide ions is important due to its high toxicity to living matter. The low cyanide detection levels established by enviromental protecion agencies for industrial wastes, demand the development of accurate and selective analytical methods. Measurement of cyanide was carried out after pretreatment of the sample by destillation, as recommended for the APHA (American Public Health Association), releasing cyanide in the form of HCN, which was collected, processed in FIA (Flow Injection Analysis) system and quantified spectrophotometrically. The optimization of the FIA system was done after some stages of study involving interpretation and analysis of the obtained results for concentrations of the reagents, temperature, size of the reactors used in the system and concentration of the standard solution in one of the sampling loops. The FIA system composed two sample valves, one for introduction of a predetermined volume of standard cyanide solution of known concentration and the another for introduction of the calibration solutions or samples. In order to get results, analytical curves were constructed, by using of the cyanide standards containing 0,01 to 0,04 mg.mL-1, which was used in the analysis of the 6 (six) effluent samples of oil refinery. The results were validated by comparison these obtained by using classic methodology recommended by APHA (Standard Methods for the Examination of Water and Wastewater). The developed method of easy application and of low cost, and can be used with confidence, because the results obtained with the standard method were comparable with the found ones with the automatic spectrophotometric method considered. The detection limit for cyanide was 0,02 μg.mL-1, adequate for the determination of cyanide in industrials effluents
Toresson, Caroline. "Påverkan på blodgassprutor som transporterats i rörtransportsystemet MC-2000". Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-85818.
Texto completoBlood gas syringe are ordered to examine the patient´s acid-base status, lactate concentration and electrolyte concentration. Some causes for imbalance could be trauma, lack of oxygen, infection, poisoning or starvation. In 2018, a new pneumatic tube transport system was installed at Västervik´s hostpital and the purpose of this study was to investigate if it is possible to transport samples for blood gas analyses with the new pneumatic tube transport system without affecting the test results. The analyses which were investigated were pH (power of hydrogen), oxygen tension, carbon dioxide tension, saturation, sodium ions, potassium ions, free calcium ions, standard bicarbonate, base excess and lactate. The study included 27 arterial double samples, one samples was transported in the pneumatic tube transport system and the other was manually transported to the laboratory. The samples were analysed within 30 minutes after the sampling, on the ABL 800 Flex instrument, using the methods potentiometry, amperometry and spectrophotometry. The results were compared using a correlation diagram with a regression line to study the relationship between the parameters. The correlation diagram shown a positive linear correlation and a relationship could be demonstrated for all the parameters (r = 0,929-0,998). If the results from the samples transported manually increased, the results also increased from the samples transported in the pneumatic tube transport system and vice versa. A bar chart was created to visualize differences in the mean values. A difference could be seen in base excess and the mean value increased after transport in the pneumatic tube transport. A two-sided paired t-test was performed to demonstrate any significant difference between the parameters. The t-test demonstrated a significant difference in the oxygen tension (p = 0,04), oxygen saturation (p = 0,04), base excess (p = 0,001) and the standard bicarbonate (p = 0,006) and statistically the values was higher after transport with the pneumatic tube transport system. The mean value for sodium ions decreased after transport in the pneumatic tube transport system and that indicate that hemolysis did not occur. The conclusion of the study was that there is a significant difference between blood gas syringes transported with pneumatic tube transport system and blood gas syringes transported manually, but the differences are not clinically relevant.
Alves, Evandro Roberto. "Sistemas de análises químicas em fluxo explorando multi-impulsão, interface única ou quimiometria". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-14052010-092516/.
Texto completoMulti-pumping flow systems (MPFS) present as an unique feature the use of solenoid pumps as fluid propelling devices, which deliver pulsed flows. This flow regime was evaluated in order to improve mixing conditions between the involved solutions, heating transfer and gas diffusion.The association of the chemometric methods of analysis and MPFS systems was demonstrated in the spectrophotometric determination of glucose, fructose and glycerol in musts and sugar cane juices. The method involved metaperiodate oxidation of carbohydrates and further oxidation of remainder metaperiodate iodide yield in the [I3 -] complex that was spectrophotometrically monitored. Data treatment involved multivariate calibration relying on the PLS algorithm and results were in agreement with liquid anion chromatography with pulsed amperometric detection. The proposed system is simple and rugged, allowing 120 samples to be run per hour. The pulsed flow led to a enhanced in heating transfer and gas diffusion, in view of the enhanced radial mass transport. These aspects were verified in the spectrophotometric determination of total reducing sugars (TRS) and ethanol. The proposed MPFS system for TRS determination involved in-line hydrolysis of sucrose and alkaline degradation of the carbohydrates. The intrinsic characteristic of pulsed flow allowed the use of lower temperatures in bath thermostatization during hydrolysis and degradation steps, as well as a lower alkalinity. The MPFS for spectrophotometric determination of ethanol involving diffusion towards an acceptor stream, reduction of Cr(VI) to Cr(III) under acidic condition, and Cr*(III) monitoring proved to be eficient and amenale to analytical procedures involving gas diffusion. After optimization of the main parameters, the system was compared with a multicommuted flow system (MCFA) that exploits a laminar flow. Better analytical results were obtained with the proposed system which demonstrated fair sensitivity. Regarding flow systems exploiting a single reaction interface (SIFA), their potentialities were demonstrated by implementing analytical procedures for simultaneous determination without requiring reconfigurations in the flow manifold. In this proposed system the simplification of the optimization step was atained, and the approach was evaluated in relation to spectrophotometrically determination of aluminum, total iron and phosphate. The system exhibits simple configuration and allows 130, 140 and 90 samples of aluminum, total iron and phosphate to be run per hour, respectivelly
YAMAGUISHI, RENATA B. "Especiação de alumínio em águas subterrâneas na região do manancial Billings: aplicação da radiação ionizante na digestão amostral para fins analíticos e na proposta de remediação". reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10568.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Fortes, Paula Regina. ""Calibração multivariada e cinética diferencial em sistemas de análises em fluxo com detecção espectrofotométrica"". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/64/64132/tde-14082006-120124/.
Texto completoDifferential kinetic analysis can be implemented in a flow system analyser, and this was demonstrated in designing an improved spectrophotometric catalytic determination of iron and vanadium in Fe-V alloys. The method relied on the influence of Fe2+ and VO2+ on the rate of the iodide oxidation by Cr2O7 under acidic conditions; therefore the Jones reductor was needed. To this end, a flow injection system (FIA) and a multi-pumping flow system (MPFS) were dimensioned and evaluated. In both systems, the alloy solution was inserted into an acidic KI solution that acted also as carrier stream, and a dichromate solution was added by confluence. Successive measurements were performed during sample passage through the detector, each one related to a different yet reproducible condition for reaction development. Data treatment involved multivariate calibration by the PLS algorithm. The FIA system was less recommended for multi-parametric determination, as the laminar flow regimen could not provide suitable kinetic information. On the other hand, a MPFS demonstrated that pulsed flow led to enhance figures of merit due to chaotic movement of its fluid elements. The proposed MPFS system is very simple and rugged, allowing 50 samples to be run per hour, meaning 48 mg KI per determination. The first two latent variables carry ca 94 % of the analytical information, pointing out that the intrinsic dimensionality of the data set is two. Results are in agreement with inductively coupled argon plasma optical emission spectrometry.
Batista, Guilherme Lopes. "Análise da acetona em ar exalado: metodologia para estudo em pacientes hospitalizados". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-13122010-102634/.
Texto completoThe dissertation fits in the research field of noninvasive clinical analysis, more specifically, the prognosis of the severity of heart failure, HF, based on a biomarker found in the air exhaled by patients, in a study at InCor-HCFMUSP. The most relevant biomarker found by GC-MS was acetone (propanone). For the breath collection a device was developed which comprises a scrubber flask (impinger) with diffuser, containing 5 mL of water, immersed in an ice bath and attached to a plastic bag for delimitation of the sample volume (7,6 L). For the determination of acetone a spectrometric method (474 nm) was chosen based on a reaction of acetone with salicylaldehyde in alkaline medium, with detection limits of 0,3 mg/L in liquid phase and 0,3 µg/L in breath. Preliminary studies made with samples collected from HF patients by the co-workers from InCor indicate the potential of the identified biomarker and the suitability of the equipment and methods developed in this dissertation for its analysis.
Junior, Orlando Guarilha. "A derivatização na determinação de proteínas e aminoácidos em fluidos biológicos". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-16022018-150518/.
Texto completoThis work describes two methods for analysis of total proteins and aminoacids using both p-benzoquinone (PBQ) and tetraamin copper (II) reagents. With the p-benzoquinone reagent the method was performed by an original flow system made with stainless steel capillary tubing, conveniently heated into a glycerin bath, where the reactional mixture travels in its way to the detector. The derivate products are carried out to a flow cell adjusted to a spectrophotometer where the absorbances are measured. This method was efficient, with a fair cost, and providing results very faster than in the batch mode of operation. The second method, using the tetraamin copper (II) reagent, was performed by a common flow injection system (FIA). When compared with the PBQ method, the FIA tetramin copper (II) method was also rapid, efficient, with a fair cost and with the great advantage of simplicity, once it is performed at room temperature. The results obtained with human albumine samples using both methods are in agreement with those ones obtained by the Kjeldahl method for the same samples.
Sasaki, Milton Katsumi. "Projeto e desenvolvimento de um sistema de análises químicas por injeção em fluxo para determinações espectrofotométricas simultâneas de cobre e de níquel explorando cinética diferencial e calibração multivariada". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-08022012-094037/.
Texto completoDifferential kinetic analysis exploits the differences in reaction rates between the analytes and a common reactant system; prior steps of analyte separation can then be waived. Flow-injection systems (FIA) are considered as an important tool for methods involving such a strategy because they allow precise control of sample / reagent dispersion and timing. The aim of this work was then to exploit these two favorable aspects for the simultaneous determination of copper and nickel using the 5-Br-PADAP chromogenic reagent. Three sample aliquots were simultaneously inserted by means of a proportional injector into reagent carrier stream (75 mg L-1 5-Br-PADAP + 0.5 mol L-1 acetic acid / acetate, pH 4.7) of a single-line FIA system. During transport towards detection, the established zones coalesce themselves, resulting in a complex zone that was monitored at 562 nm. The local maximum and minimum values of the concentration / time obtained function were considered for multivariate calibration using the PLS-2 (partial least squares - 2) chemometric tool. The reagent concentration, buffering capacity, temperature, flow rate and lengths of the analytical path, sampling loops and initial distance between plugs were established and evaluated for the construction of mathematical models. To this end, 24 Cu2+ and Ni2+ (0.00 - 1.60 mg L-1, also 0.1% v/v HNO3) mixed standard solutions were used. Two latent variables were enough to capture > 98% of the variance inherent in the data set and average prediction errors (RMSEP) were estimated as 0.025 and 0.071 mg L-1 for Cu and Ni, emphasizing the good precision the calibration model. The proposed system presents good figures of merit: physical stability when kept in operation for four uninterrupted hours, consumption of 314 \'mü\'g 5-Br-PADAP per sample, sample throughput of 33 h-1 (165 data, 66 determinations) and error readings in absorbance signals typically <5%. However, inaccuracy of the predictions made by the proposed model when compared to results obtained by ICP OES was noted. Thus, further studies involving this type of matrix, as well as masking techniques of potential interferences present, are recommended
Gomes, Taciana Figueiredo. "Determinação espectrofotométrica de sulfato em águas de chuva em um sistema de análises químicas em fluxo envolvendo troca-iônica". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-22052013-094046/.
Texto completoA flow injection system was developed and applied to the spectrophotometric determination of low concentrations of sulphate in rain waters. The method exploits the displacement reaction involving the sulphate anion and the barium dimethylsulfonazo (III) complex, Ba-DMSA, with consequent formation of the slightly soluble BaSO4 salt. As the Ba-DMSA solution is characterized by a high molar absorptivity at 656 nm, a pronounced absorbance lessening is observed in the presence of sulphate. The analytical signal is then recorded as an inverted peak proportional to the sulphate content in the sample. Presence of dimethylsulphoxide, DMSO, at high concentrations in the reaction medium leads to an enhancement of the analytical signals, coordinating water molecules, thus improving the sensitivity of the method. Addition of the surfactant sodium dodecylsulphate, SDS, results also in a pronounced improvement in sensitivity, as its presence in the reaction medium alters the supersaturation conditions. The sensitivity and selectivity of the method were improved by including an in-line ion exchange mini-column with the anionic resin Dowex 1-X8 into the manifold, for sulphate concentration and separation from potential interfering ions. The proposed system is robust and provides accurate results (R.S.D. <0.01) at an analytical frequency of 30 determinations per hour. About 0.17 \'mü\'mol DMSA are consumed per determination. The analytical curve is linear up to 2.0 mg L-1 SO42- and the detection and quantification limits were estimated as 0.01 mg L-1 SO42- and 0.04 mg L-1 SO42-.
Campos, Paulo Roberto Paiva. "Desenvolvimento de metodologia capaz de detectar e quantificar misturas de corantes em sucos artificiais em p?" Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17792.
Texto completoFoi desenvolvido um m?todo para detectar e quantificar misturas de corantes em sucos artificiais em p? fabricados no Brasil, de diferentes marcas e sabores. Foram estudados 6 corantes artificiais: amarelo tartrazina, amarelo crep?sculo, vermelho ponceau 4R, vermelho bordeaux S, vermelho 40 e azul brilhante presentes de forma unit?ria ou em misturas nos sucos com sabores laranja, tangerina, maracuj?, abacaxi, lim?o e uva. A identifica??o dos corantes nas amostras foi feita atrav?s da compara??o com os espectros dos padr?es, utilizando-se a an?lise por infravermelho m?dio e pelos respectivos valores de absor??o m?xima nos comprimentos de onda relativos aos padr?es e valores de refer?ncia na literatura. Tamb?m foram estudados os perfis de decomposi??o t?rmica por termogravimetria, termogravimetria derivada e calorimetria diferencial explorat?ria dos corantes e dos sucos em p?, sendo determinados os teores de umidade, de mat?ria org?nica e de cinzas. O teor de umidade encontrado n?o ultrapassou 4% para todas as amostras de suco analisadas. Com rela??o ao teor de mat?ria org?nica obteve-se para 57% dos sucos analisados um teor m?dio de 51,3% e para 43% das outras amostras obteve-se uma m?dia de 67,2 %. Os resultados obtidos para o teor de cinzas indicaram que 29% das amostras apresentaram um teor de 26,7% para esse par?metro enquanto 71% das amostras apresentaram um teor de cinzas de 46,4%. Os resultados obtidos por an?lise t?rmica mostraram-se adequados considerando-se que para obter os resultados pelo m?todo tradicional h? um investimento maior de tempo, de pessoal envolvido e de material, al?m da prote??o ao meio ambiente. Para a an?lise por espectroscopia de absor??o molecular foi proposta uma equa??o simplificada para a determina??o de cada corante na mistura utilizando-se a lei de Beer. Para valida??o, empregou-se a espectroscopia de absor??o molecular no vis?vel, onde foi investigada a influ?ncia dos interferentes (TiO2 e a??car) presentes nas amostras de sucos, os testes de fotodegrada??o e a avalia??o do efeito do pH. Para quantifica??o tomou-se como refer?ncia 512 amostras sint?ticas contendo um e dois corantes (1,5625 a 25,000 mg L-1) para obten??o das curvas anal?ticas que foram aplicadas ? an?lise dos sucos em p?. Os resultados indicaram que o teor m?ximo do amarelo crep?sculo foi encontrado nos sucos com os sabores laranja, tangerina e manga que correspondeu a 25,6% da ingest?o di?ria aceit?vel (para ser ultrapassada corresponderia a ingest?o de 4 copos). O teor m?ximo encontrado para o amarelo tartrazina nos sucos foi para o sabor maracuj? que correspondeu a 8,5% da ingest?o di?ria aceit?vel, (para ser alcan?ado corresponderia a ingest?o de 12 copos). O m?todo proposto foi testado e validado com sucesso para amostras de sucos em p? sendo de simples execu??o e de rapidez na obten??o dos resultados
Dias, Tuanne dos Reis. "Desenvolvimento de instrumentação e procedimentos analíticos automáticos empregando fotometria em fase sólida para determinação de zinco em produtos farmacêuticos e água". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-23112010-112530/.
Texto completoIn this work, it is propose the instrumentation and automatic analytic procedures development using solid phase spectrophotometry for determination of zinc in pharmaceutical preparations and water. For analytic procedure implementation, the whole system was coupled to a computer through an electronic interface. A written software in language QuickBASIC 4.5 allows the computer makes the sample solutions addition control and of eluent and do data acquisition. The detection system is constituted of a flow cell contend, a LED and a photodiode. The flow cell geometry enabled vary the length of the optical path. The procedure for zinc determination was going based in analyte retention in the solid phase (TAN-C18), previously inserted in the flow cell, followed by an elution stage. With the optimized analytic parameters it btained lineal answer in the band of 0,05 to 0,85 mg L-1 (R=0,995), limit detection of 9,3 \'mü\'g L-1, variation coefficient of 1,4% (n=10) and sampling throughput of 36 det h-1. The analysis module was going applied in pharmaceutical preparations samples and the exactness of the results was going ascertained comparing with the results obtained for inductively coupled plasma optic emission spectrometry of with ICP- its. Applying appropriated statistical treatment, it observed that there wasn\'t significant difference to the reliable level of 95 %. These results prove photometer job viability of LED in photometry in solid phase
QUEIROZ, CARLOS A. da S. "Terras raras: fracionamento, purificação e controle analítico". reponame:Repositório Institucional do IPEN, 1988. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11634.
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Dissertacao (Mestrado)
IEA/D
Instituto de Quimica, Universidade de Sao Paulo - IQ/USP
Sakamoto, Junior Antonio Setsuo. "AVALIAÇÃO DA ESTABILIDADE DE COR DE LAMINADOS CERÂMICOS APÓS CIMENTAÇÃO ADESIVA". UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2015. http://tede2.uepg.br/jspui/handle/prefix/1703.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Thin ceramic laminates have been widely requested by patients because it’s a reliable conservative aesthetic procedure, stable and presents adequate longevity. It is known that the color change of the cement below these thin restorations may result inappropriate final color. Thus, the purpose of this in vitro study was to evaluate the color agreement between pressable lithium disilicate ceramics with tryin pastes and corresponding resin cements, determination of the degree of conversion of resin cements using FT-Raman spectroscopic and color stability after artificial accelerated aging (AAA) for 300 hours. Eighty-four ceramic discs (0.3 mm, 0.5 mm, 1.0 mm thick) were prepared (IPS e.maxPress HT A2 – Ivoclar Vivadent) to simulate veneers. Evaluation the baseline color was done in the CIE-L*a*b* color space with reflectance spectrophotometer (control group). The try-in pastes were applied into the interlayer of the ceramic (simulation of selection color procedure) above silicon transparent matrix (0.1 mm thick) and the color complex were measured using a spectrophotometer (n=7), with no substrate. The same ceramic discs were used for cementation procedure with Variolink II (only base),after storage in distilled water, protected from light, at 37ºC for 24 hours, the specimens were mensured the color and submitted to FT-Raman spectroscopy to determinate the degree of conversion (DC). After that, the specimens were AAA for 300 hours and measured by spectrophotometer to calculate ΔE. Two-way ANOVA was used to analyze the data. Tukey’s post hoc for multiple comparisons and Spearman correlation test were performed (α = 0.05). There was no agreement between the try-in with resin cements, L* and b* values increased, increasing the value/opacity,yellowish of the complex. All groups exhibited values of ΔE>3.3, except resin color A3 group (1.0 mm ceramic thickness). Ceramic thicknesses (0.3 mm and 0.5 mm) did not affect the DC compared to the control (p> 0.05). Thus, DC was influenced by the color of cement, where the over saturated color showed higher conversion rate, DC decreased when ceramic disc thickness increased. No correlation between DC and ΔE was observed.
A modalidade indireta de restauração denominada laminado cerâmico, vem sendo vastamente solicitada pelos pacientes, por se tratar de um procedimento confiável, estável, conservador, estético e apresenta longevidade aceitável. Sabe-se que a alteração de cor do cimento localizado abaixo destas restaurações delgadas pode influenciar negativamente no aspecto estético final. Desta forma, o propósito do presente estudo in vitro foi avaliar a concordância da coloração da pasta de prova e seu respectivo cimento resinoso, verificar o grau de conversão deste pelo método Micro-Raman e sua estabilidade de cor após envelhecimento artificial acelerado (EAA) por 300 horas. Foram confeccionados 84 discos cerâmicos com sistema IPS e.maxPress HT (Ivoclar Vivadent) na cor A2 com 3 espessuras (0.3 mm, 0.5 mm, 1.0 mm) cuja coloração foi mensurada com espectrofotometria de refletância (grupo controle). Em seguida, foi realizada a simulação da seleção da cor do cimento Variolink II (try in Transparente, Opaco, A3) e mensurada a cor do conjunto nas coordenadas CIEL* a*b*. Depois foi realizada a cimentação adesiva (mesmos discos cerâmicos utilizados com try in) com três cores de cimentos resinosos (Base: Transparente, Opaco, A3), sobre uma matriz de silicone transparente com cavidade de espessura de 0,1 mm (n=7), sem qualquer substrato. Após armazenamento com água destilada, protegido da luz, em estufa a 37ºC por 24h, os corpos de prova (cp) foram submetidos novamente ao teste de espectrofotometria e ao teste grau de conversão (GC) pelo método FT-Raman. Em seguida, foram submetidos ao EAA por 300 horas e mensurada a coloração para verificar se houve alteração (ΔE). Os dados coletados foram submetidos à ANOVA 2 fatores, seguido pelo pós-teste de Tukey e pelo teste de correlação de Spearman (α=0,05). Não houve concordância entre o try in e respectivo cimento, os valores de L* e b* aumentaram, tornando mais luminosa/opaca e amarelada. Todos grupos apresentaram valores superiores de ΔE=3,3, exceto o grupo do cimento cor A3 (cerâmica espessura de 1,0 mm) e as espessuras cerâmicas de 0,3 e 0,5 mm não influenciaram o GC, onde apresentaram valores sem diferença significativa (p>0,05) comparada ao grupo controle. Assim, o GC foi influenciado pela cor do cimento, onde o mais saturado apresentou maior taxa de conversão, ao passo que o valor de GC diminuiu quando a espessura do disco cerâmico interposto aumentou. Não houve relação entre o GC e ΔE.
Miranda, Jeová Correia. "Desenvolvimento de um equipamento portátil e de sistema de análises em fluxo empregando multicomutação. Determinação fotométrica de ferro em águas de rios". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-30092011-100908/.
Texto completoIron is the most abundant element on Earth and plays an important role in biogeochemical cycles. In this work, an automatic analytical procedure was developed for the photometric determination of iron in river waters, employing a LED-based photometer and solenoid mini-pumps for solution handling. The proposed procedure was based on the reaction between iron (III) and potassium thiocyanate, yielding a red complex with maximum absorption at 470 nm. For the determination of total iron, an in line oxidation step was included, employing a persulfate solution (S2O82-) as oxidant. The module was constructed with four solenoid mini-pumps and a three-way solenoid valve. For data acquisition a photometer was constructed with a 50 mm optical path flow cell, a blue LED (\'lâmbda\'= 470 nm) and a photodetector. Envisioning the use of this portable equipment in field, two 6-Volt batteries were employed to supply energy to the active devices. Laboratory tests showed that the batteries provide more than 50 hours of operation without recharging. The proposed procedure showed the following analytical features: linear response between 0.25 and 4.0 mg L-1, according to the equation Y = (0.0183 ± 0.003) + (0.15326 ± 0.002) X (r = 0.9997); detection limit of 0.013 mg L-1 Fe (III), estimated with 99.7 % of confidence; relative standard deviation estimated as 0.95% (n = 15), obtained with a 1.5 mg L-1 Fe (III) solution; sampling rate of 50 determinations per hour.The results obtained with the proposed and reference procedure did not show significative differences at a 95% confidence level
Dias, Tuanne dos Reis. "Desenvolvimento de procedimentos analíticos empregando multicomutação em sistemas de análises em fluxo para determinação fotométrica de vanádio em águas e estanho em alimentos". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-26012015-150109/.
Texto completoAutomatic analytical procedures for photometric determinations of vanadium in water and tin in foods were developed using the multicommutation flow analysis process. A microcontroller of the PIC family and a software written in Visual Basic 6.0 language were used for devices control and data acquisition. Detection unit was designed to use high brightness LED and long optical pathlength flow cells (50-200 mm) to improve sensitivity. The flow analysis module using solenoid mini-pumps as fluid propelling devices and the photometer were integrated in order to form a compact unit. The determination of vanadium in mineral and river waters was based on the reduction of V(V) to V(IV) with ascorbic acid and subsequent complexation with Eriochrome Cyanine R (ECR). Employing flow cell of 150 mm, the system presented linear response between 0.02 and 1.00 mg L-1, detection limit of 13 ?g L-1, variation coefficient of 0.87% (n=10) and sampling throughput of 47 determinations per hour. Recoveries between 89 and 109% were attained for vanadium spiked to mineral and river water. The procedure for determination of tin in foods was development employing a multi-syringe pump as fluid propelling device, a flow cell with optical pathlength of 200 mm and stop flow of 50 s. The procedure was based on the reaction of Sn(IV) with pyrocatechol violet (PCV) in the presence of surfactants, presented linear response between 0.10 and 1.25 mg L-1, detection limit of 0.04 mg L-1, variation coefficient of 1.30% (n=10) and sampling throughput of 49 determination per hour. Recoveries between 95 and 115% were attained for tin spiked samples
Silva, Marcelo Solitrenick Pinto. "Procedimentos de análise por injeção sequencial para determinação espectrofotométrica de sulfeto em amostras ambientais explorando a formação do azul de metileno". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-16022018-165844/.
Texto completoThis thesis demonstrates the application of sequential injection analysis (SIA) to perform sulfide determination using the methylene blue chemistry, based on two reagents: 3.63 mmol L-1 N,N dimethyl-p-phenylene diamine hydrochloride in 1.1 mol L-1 HCI solution and 19 mmol L-1 FeCl3, also in 1.1 mol L-1 HCI. These solutions are aspirated inside the holding coil of the sequential injection system as two reagent zones sandwiching the sample zone. Under optimized conditions, the detection limit was calculated at 40 µg L-1 S2-, with a linear dynamic range from 0.05 to 2 mg L-1 S2-. This linear range can be extended up to 32 mg L-1 using in-line dilution for sulfide concentrations greater than 2 mg L-1. The robust characteristic of the SI system with syringe pump leads to very stable analytical curves (precision of 4%), minimizing the laborious preparation of sulfide standards. The method was applied in the determination of acid volatile sulfide in river sediments collected at the Metropolitan Area of São Paulo (MASP) City and at the Barra Bonita reservoir, located in the Tietê River, 270 km down river from São Paulo City. The concentrations of acid volatile sulfide were 9 to 14 mg kg-1 in the Barra reservoir and between 1.2 and 14 g kg-1 in sediments from Billings, Pirapora and Rasgão reservoirs. This thesis also describes the coupling of Sequential Injection with Monosegmented Flow Analysis (SI-MSFA) for determination of sulfide at typical concentrations in wastewaters. The analytical curves were constructed by in-line dilution of a single stock standard solution. The robustness of the proposed method was checked constructing analytical curves in different working days and comparing the slopes, which had a relative standard deviation of 5.2 % (n = 5) for a concentration window inside the monosegment between 0.17 and 1.0 mg L-1 S2-. The analytical throughput was 38 samples per hour and the limit of detection was 40 µg L-1. The feasibility of the SI-MSFA approach to perform standard additions for S2- determination was also described. Simulated samples analyzed by the proposed method showed recoveries between 70 and 115%, demonstrating the feasibility of the SI-MSFA method to perform in-situ analysis of S2- in automatic monitoring stations.
Melchert, Wanessa Roberto. "Desenvolvimento de procedimentos analíticos limpos e com alta sensibilidade para a determinação de espécies de interesse ambiental". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-25062009-150929/.
Texto completoClean analytical procedures with high sensitivity for the determination of species of environmental interest (carbaryl, sulphate and chlorine) were developed. Flow systems with solenoid micropumps were coupled to long optical pathlength spectrophotometry or cloud point extraction procedures, aiming the concentration of species for determination without employing toxic solvents. Carbaryl determination in natural waters was based on a double cloud point extraction: a clean-up step for removal of interfering organic species and pre-concentration of the indophenol blue, formed in the reaction with the oxidized of p-aminophenol. Linear response was observed between 10 and 50 µg L-1, with apparent molar absortivity estimated as 4.6x105 L mol-1 cm-1. Detection limit was estimated as 7 mg L-1 and the coefficient of variation as 3.4% (n = 8). Recoveries between 91 and 99% were obtained for carbaryl spiked to natural waters. A simple and low cost flow cell with 30 cm optical path was constructed for spectrophotometric measurements. The cell shows desirable characteristics such as reduced attenuation of the radiation beam and internal volume (75 µL) comparable to conventional flow cells. The performance was evaluated by phosphate determination by the molibdenium blue method, with linear response between 0.05 and 0.8 mg L-1 of phosphate (r = 0.999). The increase in sensitivity (30.4 fold) in comparison to the obtained with a conventional 1 cm optical path flow cell agreed to theoretical value estimated by the Lambert-Beer law. The determination of carbaryl was also carried out in a flow system coupled to 30 and 100 cm optical path flow cells, also exploiting the formation of indophenol compound. Linear responses, detection limits and coefficients of variation were 50 - 750 and 5 - 200 µg L-1;4.0 and 1.7 µg L-1 and 2.3 and 0.7%, respectively, for 30 and 100 cm cells. The proposed procedure was selective for the determination of carbaryl, without interferences of other carbamate pesticides. The waste of the analytical procedure was treated with potassium persulphate and ultraviolet irradiation, with decrease of 94% of total organic carbon. The residue after treatment was not toxic for Vibrio-fischeri bacteria. Sulphate determination was based on turbidimetric measurements with 1-cm flow cell, with linear response between 20 and 200 mg L-1. Baseline drift was avoided in view of the pulsed flow related to the solenoid micropumps. The detection limit and the coefficient of variation were estimated as 3 mg L-11 and 2.4%, respectively, for a sampling rate of 33 determinations per hour. Aiming the increase in sensitivity, a 100 cm optical path flow cell was employed and baseline drift was avoided with a washing, step employing EDTA in alkaline medium. Linear response was observed between 7 - 16 mg L-1, with a detection limit of 150 µg L-1, coefficient of variation of 3.0% (n = 20) and sampling rate of 25 determinations per hour. Results obtained natural and rain for water samples agreed at 95% confidence level with the batch turbidimetric procedure. The determination of free chlorine in natural and tap waters was based on the reaction with N,N-diethyl-p-phenylenediamine, with linear response between 5 and 100 µg L-1, and detection limit and coefficient of variation estimated as 0.23 µg L-1 and 3.4%, respectively. Sampling rate was estimated as 58 determinations per hour.