Tesi: "Chromatographic analysis"

1

McBrady, Adam Dewey. "Microfabricated chromatographic instrumentation for micro total analysis systems /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8570.

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2

Galindo, Irma C. (Irma Concepcion). "Investigation Into the Causes for the Loss of Resolution in an Ion Chromatograpy Resin". Thesis, North Texas State University, 1988. https://digital.library.unt.edu/ark:/67531/metadc798197/.

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Four mechanisms were considered as possible causes of the loss in resolution for a Dionex CG2 ion chromatography resin: 1) presence of inorganic ions strongly bound to the active sites; 2) adsorption of organic species; 3) physical alterations; and 4) chemical alterations. The instrumental analyses used to gather data were ICP, FT-IR, SEM, solid C-13 NMR and IC. Based on the results, no metal ions are bound to the resin, no organic species are held onto the resin, and no physical change was observable. The cause for the loss of resolution is a strong reduction in the number of active sites in the resin as confirmed by elemental analysis for the sulfur in the sulfonic acid present in the active sites.

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3

Prazen, Bryan J. "Development of high speed hyphenated chromatographic analyzers and second order data analysis techniques /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11550.

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4

Kirk, John Daniel. "Particle beam LC/MS with fast atom bombardment". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/27127.

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5

Michelsen, Peter J. "Relationship between chromatographic retention and donor and acceptor numbers /". Online version of thesis, 1990. http://hdl.handle.net/1850/10688.

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6

Wong, Victor, University of Western Sydney, of Science Technology and Environment College e of Science Food and Horticulture School. "A fundamental study towards improving the performance of liquid chromatographic separation". THESIS_CSTE_SFH_Wong_V.xml, 2003. http://handle.uws.edu.au:8081/1959.7/467.

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The three factors of the resolution (Rs)equation(see Equation 1.1)were explored in this thesis. During the course of the research project, an important aim was to explore separation processes that would lead to an increase in productivity without sacrificing Rs. To that end, an increase in the retention factor (k)to enhance Rs was deemed detrimental to the cycle time, hence the production rate, particularly when preparative separations are involved. Consequently the primary objectives were to (i)prepare more efficient columns and (ii)investigate new strategies in manipulating selectivity. The significance of the work contained in this thesis is highlighted in 27th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2003)held in Nice, France between 15-19 June, 2003. Many of the papers presented significantly compared to chapters contained in this research
Doctor of Philosophy (PhD)

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7

Wong, Victor. "A fundamental study towards improving the performance of liquid chromatographic separation". Thesis, View thesis, 2003. http://handle.uws.edu.au:8081/1959.7/467.

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The three factors of the resolution (Rs)equation(see Equation 1.1)were explored in this thesis. During the course of the research project, an important aim was to explore separation processes that would lead to an increase in productivity without sacrificing Rs. To that end, an increase in the retention factor (k)to enhance Rs was deemed detrimental to the cycle time, hence the production rate, particularly when preparative separations are involved. Consequently the primary objectives were to (i)prepare more efficient columns and (ii)investigate new strategies in manipulating selectivity. The significance of the work contained in this thesis is highlighted in 27th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2003)held in Nice, France between 15-19 June, 2003. Many of the papers presented significantly compared to chapters contained in this research

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8

Silwal, Indira K. C. "Characterization of Unknown Chemicals Using Gas Chromatography/Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and AB-Initio Calculations". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SilwalIKC2008.pdf.

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9

Allyn, M. Liz. "Indirect photometric chromatography of iodide ion in aqueous solutions /". Online version of thesis, 1987. http://hdl.handle.net/1850/8769.

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10

Brückner, Carsten Albrecht. "Rapid chromatographic analysis using novel detection systems and chemometric techniques /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11573.

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11

Banyard, Alan Frederick. "Chromatographic and spectroscopic analysis of Erythrina alkaloids". Thesis, Cardiff University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284511.

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12

Kang, Jasjit. "The chromatographic and spectrochemical analysis of foodstuffs". Thesis, University of Surrey, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335390.

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13

Stubbs, Christopher. "High performance liquid chromatographic analysis of erythromycin in serum and urine". Thesis, Rhodes University, 1985. http://hdl.handle.net/10962/d1004581.

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Erythromycin, a macrolide antibiotic used mainly against gram-positive bacteria has been in clinical use since 1952 (1). Previous pharmacokinetic data published on this antibiotic have been derived predominantly from microbiological assay techniques. However, these techniques are relatively imprecise as well as being non-specific and extremely tedious to perform. A novel high performance liquid chromatographic analysis of erythromycin in human serum and urine using U.V. detection at 200 nm and/or electrochemical detection using both an amperometric and a coulometric electrochemical detector is presented. The method involves a solid phase extraction procedure followed by a simple phase separation step and chromatography on a reverse phase column. In order to select the optimum U.V. detector for this analysis, five "state of the art" detectors were compared in terms of their signal-to-noise ratios at U.V. wavelengths between 200 and 210 nm. A known metabolite des-N-methylerythromycin is readily detectable using U.V. detection, whilst another metabolite/degradation product anhydroerythromycin is not seen using U.V. detection but is readily observable using an electrochemical detector. The method has a limit of sensitivity of 0.25 μg/mL and 1.00 μg/mL in serum and urine respectively (U.V. detection) and is sufficiently sensitive to monitor serum and urine concentrations of erythromycin in man after administration of a single 500 mg erythromycin stearate tablet.
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14

Cao, Liming. "Protein Separation with Ion-exchange Membrane Chromatography". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050405-174109/.

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15

Wallace, Sheryl Kaye. "Chromatographic and spectroscopic studies of tetraphenylborate radiolysis". Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/26209.

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16

Shalliker, Ross Andrew, e mikewood@deakin edu au. "Studies on the behaviour of polystyrene in reversed phase chromatography". Deakin University. School of Sciences, 1992. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20051125.112118.

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Polystyrene behaviour in reversed phase high performance liquid chromatography was influenced mainly by the solvent system, but secondary affects were observed depending on the stationary phase. A variety of reversed phase columns were investigated using mobile phase combinations of dichlorom ethane-methanol, dichloromethane-acetonitrile, ethyl acetate-methanol and ethyl acetate-acetonitrile. Several different modes of behaviour were observed depending on the polymer solubility in the solvent system. In the dichloromethane-methanol solvent system, polymer-stationary phase interactions only occurred when the molecules had pore access. Retention of excluded polystyrene depended on the kinetics of precipitation and redissolution of the polymer. Peak splitting and band broadening occurred when the kinetics were slow and molecular weight separations were limited !o oligomers and polystyrenes lower than 5-10(4) dalton. Excellent molecular weight separations of polystyrenes were obtained using gradient elution reversed phase chromatography with a dichloromethane-acetonitrile mobile phase on C18 columns. The retention was based on polymer-stationary phase interactions regardless of the column pore size. Separations were obtained on large diameter pellicular adsorbents that were almost as good as those obtained on porous adsorbents, showing that pore access was not essential for the retention of high molecular weight polystyrenes. In the best example, the separation ranged from the monomer to 10(6) dalton in a single analysis. Very little adsorption of excluded polymers was observed on C8 or phenyl columns. Polystyrene molecular weight separations to 7-10(5) dalton were obtained in an ethyl acetate-acetonitrile solvent system on C18 columns. Adsorption was responsible for retention. When an ethyl acetate-methanol solvent system was used, no molecular weight separations were obtained because of complex peak splitting. Reversed phase chromatography was compared to size exclusion chromatography for the analysis of polydisperse polystyrenes. Similar results were obtained using both methods. However, the reversed phase method was less sensitive to concentration effects and gave better resolution.

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17

Ong, Wen-ching. "Characterization of Aquatic Fulvic Acids by Chromatographic Methods". Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc332576/.

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Several chromatographic and spectroscopic techniques were applied to Suwanne River reference fulvic acids (FA) and their permethylated derivatives. Retention mechanisms, structural characteristics, and thermal stabilities of FA and its derivatives and fractions were evaluated.

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18

Willemse, Chandre Monique. "Comprehensive two-dimensional liquid chromatographic analysis of anthocyanins". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96675.

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Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Anthocyanins are naturally occurring pigments responsible for the colour of many natural products, including grapes and wine. These pigments are important to the food industry and have been recognised for their nutritional value since they play an important role in the reduced risk of various chronic diseases in humans. Anthocyanins also play an important role in the aesthetic perception and quality of red wine. However, due to the large structural diversity of grape-derived anthocyanins and the many derivatives formed from these during wine ageing, the accurate analysis of wine pigments is extremely challenging. Reversed-phase liquid chromatography (RP-LC) is mostly used for anthocyanin analysis, although the technique often provides insufficient resolving power for complex mixtures of anthocyanins. In addition, the lack of commercially available standards and identical mass spectral characteristics hampers identification of these compounds. The coupling of multiple orthogonal separation systems in comprehensive 2-dimensional liquid chromatography (LC×LC) offers a more powerful approach for the separation of complex mixtures. The current work therefore focussed on exploring the potential of LC×LC for the improved analysis of anthocyanins and derived pigments in natural products and wine. The first part of this work focussed on developing a hydrophilic interaction chromatography (HILIC) method as an alternative to RP-LC for the anthocyanin analysis. Following extensive optimisation, the method proved suitable for the analysis of a diverse range of anthocyanins in natural products. Significantly, it also showed alternative selectivity compared to RP-LC. The optimised HILIC method was then used in combination with RP-LC to develop an off-line LC×LC approach for anthocyanins. For this purpose, half-minute fractions of the HILIC effluent were collected and reinjected onto a RP-LC column. The off-line HILIC×RP-LC method demonstrated exceptionally high resolving power, as measured in terms of the practical peak capacity, with many compounds separated in two dimensions that co-eluted in 1-dimensional HPLC. Interestingly, group-type separation was also observed based on the degree and/or nature of glycosylation and acylation of anthocyanins. In the final part of the work, a systematic approach was used for the development and optimisation of and on-line HILIC×RP-LC method by using a 10-port switching valve to automatically transfer fractions between the two columns. This method was then coupled to high resolution mass spectrometry (MS) to allow the detailed investigation of anthocyanins and derived products in wine. Ninety four pigments were identified in one- and six-year old Pinotage wines based on HILIC×RPLC separation in combination with accurate mass MS data and fragmentation information. Significant differences in especially the content of derived pigments were observed between the wines. In summary, the methods developed in this work provide the means to improve anthocyanin analysis, and therefore also show promise for the detailed investigation of these important compounds and their alteration in natural products and their derived commodities.
AFRIKAANSE OPSOMMING: Antosianiene is natuurlike pigmente wat verantwoordelik is vir die kleur van baie natuurlike produkte, insluitende dié van druiwe en wyn. Hierdie pigmente is belangrik vir die voedsel industrie en word gereken vir hul voedingswaarde aangesien hulle 'n belangrike rol speel in die verlaagde risiko van verskeie chroniese siektes onder die mens. Antosianiene speel ook 'n belangrike rol in die estetiese persepsie en kwaliteit van rooiwyn. Desnieteenstaande, as gevolg van die groot strukturele diversiteit van druifgeproduseerde antosianiene en die vele chemiese afgeleides wat uit hulle gevorm kan word tydens wyn bereiding en veroudering, is die akkurate analise van natuurlike wyn-pigmente uiters uitdagend. Omgekeerde-fase vloeistofchromatografie (RP-LC) word meestal gebruik vir die analise van antosianiene. Dié tegniek bied egter dikwels onvoldoende skeidingsvermoë vir komplekse mengsels van antosianiene en verwante molekules. Verder belemmer die onbeskikbaarheid van kommersiële standaarde en identiese massa spektrale eienskappe die identifikasie van hierdie verbindings. Die kombinasie van verskillende ortogonale skeidings meganismes in omvattende 2- dimensionele vloeistofchromatografie (LC×LC) bied egter 'n baie kragtiger benadering vir die skeiding van komplekse mengsels. Die huidige werk fokus dus op die ontginning van die potensiaal van LC×LC vir die verbeterde ontleding van antosianiene en verwante afgeleide pigmente in natuurlike produkte en wyn. Die eerste deel van hierdie werk het gefokus op die ontwikkeling van 'n hidrofiliese interaksie chromatografiese (HILIC) metode as ŉ alternatief vir RP-LC analise van antosianiene. Na uitgebreide optimisering, is gevind dat die metode geskik is vir die ontleding van 'n verskeidenheid van antosianiene in natuurlike produkte. Van groot belang is dat dit ook alternatiewe selektiwiteit in vergelyking met RP-LC demonstreer. Hierdie geoptimiseerde HILIC metode word dan voorts gebruik in kombinasie met RP-LC vir die ontwikkeling van ŉ af-lyn LC×LC benadering vir die analise van antosianiene. Hiervoor is half-minuut fraksies van die HILIC uitvloei opgevang en her-ingespuit op 'n RP-LC kolom. Dié af-lyn HILIC×RP-LC metode toon buitengewoon hoë skeidingsvermoë, gemeet in terme van die bereikbare praktiese piek kapasiteit, met baie verbindings wat geskei is in die twee dimensies wat saam elueer in 1-dimensionele HPLC. Interessant genoeg is groep-tipe skeiding ook waargeneem gebaseer op die graad en / of aard van glukosilasie en asilering van die antosianiene. In die laaste deel van die werk, is 'n sistematiese benadering gevolg vir die ontwikkeling en optimisering van ŉ aan-lyn HILIC×RP-LC deur gebruik te maak van 'n 10-poort oorskakelingsklep wat fraksies outomaties oordra tussen die twee kolomme. Die bogenoemde metode is ook verder gekoppel aan hoë resolusie massaspektrometrie (HR-MS) om ŉ gedetailleerde ondersoek van antosianiene en hulle afgeleide verbindings in wyn moontlik te maak. Vier en negentig pigmente is in een- en ses jaar oue Pinotage wyne geïdentifiseer gebaseer op HILIC×RP-LC skeiding in kombinasie met akkurate massa MS data en fragmentasie inligting. Beduidende verskille in veral die inhoud van antosianien-afgeleide pigmente is tussen die wyne waargeneem. Ter samevatting, die metodes ontwikkel in hierdie werk baan die weg om antosianien ontleding te verbeter en stel gevolglik die moontlikheid van selfs meer gedetailleerde studies van hierdie belangrike verbindings in natuurlike produkte in die vooruitsig.

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19

Wong, Victor. "A Fundamental study towards improving the performance of liquid chromatographic separation /". View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20060428.124908/index.html.

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Thesis (Ph.D.) -- University of Western Sydney, 2003.
"A thesis submitted for the degree of Doctor of Philosophy (Science), School of Science, Food and Horticulture, University of Western Sydney, Richmond, New South Wales, Australia. December 2003". CD "attached to back cover of thesis is in Super Video-CD (SVCD) format showing the development of viscous fingering in realtime." Bibliography : leaves 135 - 147.

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20

Christofides, A. "Pyrolysis gas chromatographic analysis of quaternary ammonium compounds". Thesis, Cardiff University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304009.

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21

Kalili, Kathithileni Martha. "Comprehensive two-dimensional liquid chromatographic analysis of phenolics". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85749.

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Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Phenolic chemistry is quite complex; natural phenolic compounds vary widely in terms of size and chemical properties. The high structural diversity within this family presents severe analytical challenges. High performance liquid chromatography (HPLC) is the preferred method for phenolic analysis; however, conventional HPLC methods offer limited separation power and often provide incomplete separation of the large number of components present in natural phenolic extracts. Multi-dimensional chromatographic techniques have proven much more effective in the analysis of complex samples. The current study explored the potential of comprehensive two-dimensional liquid chromatography (LC×LC) for the characterisation of phenolic compounds in complex natural products, with the emphasis on proanthocyanidins (PACs). Initial work focused on the evaluation of the state of the art in phenolic analysis, to allow information which was used in the development of optimal 1-D separations for use in LC×LC. The combination of hydrophilic interaction chromatography (HILIC) in the first dimension with reversedphase liquid chromatography (RP-LC) in the second dimension afforded an orthogonal and powerful separation system for phenolics, providing separation on the basis of hydrophilicity and hydrophobicity, respectively. A detailed and systematic procedure was therefore developed to allow the optimisation and evaluation of on-line, off-line and stop-flow HILIC×RP-LC methods. Results showed that all three approaches provide much better separation performance than conventional one-dimensional LC (1-D LC) techniques. On-line HILIC×RP-LC offers automation, shorter analysis times, better reproducibility and minimal sample exposure. The off-line and stopflow methods are characterised by much higher peak capacities, but relatively long analysis times. It was also demonstrated that stop-flow operation results in negligible additional band broadening for procyanidins (PCs), implying that this method is an attractive alternative to the off-line method as it offers automation and minimal sample handling. Experimental verification of the predictions based on fundamental principles confirmed the validity of the optimisation procedure for cocoa PCs. The hyphenation of on-line HILIC×RP-LC separation with fluorescence (FL) and mass spectrometry (MS) detection methods provided enhanced resolution in a practical analysis time with the added benefit of selective detection and greater certainty in compound identification. This strategy proved much more powerful, as demonstrated by the identification of the highly complex PACs in grape seeds based on chromatographic retention data in two dimensions and accurate mass information. It was further shown that on-line coupling of HILIC×RP-LC separation with an optimised radical scavenging assay provides an improved approach for screening of individual radical scavengers in complex phenolic fractions, as demonstrated for cocoa, grape seed and green tea extracts.
AFRIKAANSE OPSOMMING: Fenoliese chemie is baie kompleks; natuurlike fenoliese verbindings varieer in terme van beide grootte en chemiese eienskappe. Hierdie hoë strukturele diversiteit binne die familie bied daadwerklike analitiese uitdagings. Hoëverrigtingvloeistofchromatografie (HPLC) is die voorkeurmetode vir fenoliese analises, maar konvensionele HPLC metodes bied egter 'n beperkte skeidingsvermoë en verskaf dikwels onvolledige skeiding van die groot aantal komponente teenwoordig in natuurlike fenoliese ekstrakte. Multi-dimensionele chromatografiese tegnieke is bewys om baie meer effektief te wees met betrekking tot die ontleding van komplekse monsters. Hierdie studie ondersoek die potensiaal van omvattende twee-dimensionele vloeistof chromatografie (LC×LC) vir die karakterisering van fenoliese verbindings in komplekse natuurlike produkte, met die fokus op pro-antosianidiëne (PAC’s). Aanvanklike werk het gefokus op die evaluering van moderne tegnieke vir fenoliese analise – inligting wat in die ontwikkeling van optimale 1-D skeidings vir die toepasing in LC×LC gebruik is. Die kombinasie van hidrofiliese interaksie chromatografie (HILIC) in die eerste dimensie met omgekeerde-fase vloeistof chromatografie (RP-LC) in die tweede dimensie verleen 'n ortogonale en kragtige skeidingsisteem vir fenoliese komponente en verskaf skeiding op grond van onderskiedelik hidrofiliteit en hidrofobiteit. ‘n Gedetailleerde en sistematiese prosedure is dus ontwikkel om die optimisering en evaluering van aan-lyn, af-lyn en stop-vloei HILIC×RP-LC metodes uit te voer. Resultate het getoon dat al drie benaderings baie beter skeidingsvermoë bied as konvensionele een-dimensionele LC (1-D LC) tegnieke. Aan-lyn HILIC×RP-LC bied outomatisering, korter ontledingstyd, beter herhaalbaarheid en minimale monster blootstelling. Die af-lyn en stop-vloei metodes word gekenmerk deur 'n veel hoër piekkapasiteit, maar relatief lang ontledingstye. Daar is ook getoon dat die stop-vloei prosedure geringe bykomende bandverbreding vir prosianodiniëne (PC’s) tot gevolg het, wat beteken dat hierdie metode 'n aantreklike alternatief is vir die af-lyn metode aangesien dit outomatisering bied en minimale monster hantering behels. Eksperimentele verifiëring van die voorspellings gebaseer op fundamentele beginsels bevestig die geldigheid van die optimalisering proses vir kakao PCs. Die koppeling van aan-lyn HILIC×RP-LC skeiding met fluoressensie (FL) en massaspektrometrie (MS) deteksie verskaf verbeterde resolusie binne 'n praktiese ontledingstyd saam met die bykomende voordeel van selektiewe opsporing en groter sekerheid betreffende die verbindings se identifikasie. Hierdie strategie was baie meer kragtig, soos gedemonstreer deur die identifisering van die hoogs komplekse PAC’s in druiwepitte gebaseer op chromatografiese behoud van die integriteit van die data in twee dimensies tesame met akkurate massa inligting. Daar is verder getoon dat aanlyn koppeling van HILIC×RP-LC skeiding met 'n geoptimiseerde radikale vangers deteksie-metode 'n beter benadering bied om die gedrag van individuele radikale vangers in komplekse fenoliese fraksies te bestudeer, soos bewys is vir kakao, druiwepitte en groen-tee ekstrakte.

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22

Cook, Daniel W. "Chemometric Curve Resolution for Quantitative Liquid Chromatographic Analysis". VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4362.

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In chemical analyses, it is crucial to distinguish between chemical species. This is often accomplished via chromatographic separations. These separations are often pushed to their limits in terms of the number of analytes that can be sufficiently resolved from one another, particularly when a quantitative analysis of these compounds is needed. Very often, complicated methods or new technology is required to provide adequate separation of samples arising from a variety of fields such as metabolomics, environmental science, food analysis, etc. An often overlooked means for improving analysis is the use of chemometric data analysis techniques. Particularly, the use of chemometric curve resolution techniques can mathematically resolve analyte signals that may be overlapped in the instrumental data. The use of chemometric techniques facilitates quantitation, pattern recognition, or any other desired analyses. Unfortunately, these methods have seen little use outside of traditionally chemometrics focused research groups. In this dissertation, we attempt to show the utility of one of these methods, multivariate curve resolution-alternating least squares (MCR-ALS), to liquid chromatography as well as its application to more advanced separation techniques. First, a general characterization of the performance of MCR-ALS for the analysis of liquid chromatography-diode array detection (LC-DAD) data is accomplished. It is shown that under a wide range of conditions (low chromatographic resolution, low signal-to-noise, and high similarity between analyte spectra), MCR-ALS is able to increase the number of quantitatively analyzable peaks. This increase is up to five-fold in many cases. Second, a novel methodology for MCR-ALS analysis of comprehensive two-dimensional liquid chromatography (LC x LC) is described. This method, called two dimensional assisted liquid chromatography (2DALC), aims to improve quantitation in LC x LC by combining the advantages of both one-dimensional and two dimensional chromatographic data. We show that 2DALC can provide superior quantitation to both LC x LC and one dimensional LC under certain conditions. Finally, we apply MCR-ALS to an LC x LC analysis of fourteen furanocoumarins in three apiaceous vegetables. The optimal implementation of MCR-ALS and subsequent integration was determined. For these data, simply performing MCR-ALS on the two dimensional chromatogram and manually integrating the results proved to be the superior method. These results demonstrate the usefulness of these curve resolution techniques as a compliment to advanced chromatographic techniques.

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23

Johnson, Kevin J. "Strategies for chemometric analysis of gas chromatographic data /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/8513.

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24

Mabakane, Elizabeth Nontombi. "The determination of distribution coefficient for some elements on the macroporous cation exchanger Amberlyst 15 using nitric acid – methanol mixtures". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2329.

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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016.
The main purpose of this study is to understand the application of ion exchange chromatography on separation of charged ions of elements. Ion exchange chromatography is an analytical method, which is used for the separation of elements, quantitation and qualitation. The use of Amberlyst 15 resin as a source of separation for metal ions has been investigated and studies in various academic disciplines such as chemistry and material science. In this research study, Amberlyst 15 resin was investigated in order to understand the separation of positively charged divalent elements ions (Zn2+, Cu2+, Co2+ and Ni2+). The use of nitric acid and methanol mixture enhanced separation of these metal ions by ensuring that nitric acid is constant and varying methanol concentration. In this study, it was found that the resin has a high affinity for the metal ions at high methanol concentration, hence the distribution coefficient values increase but decreases at low methanol concentrations. The complexities of molecular structure of the salts of the elements provide the more understanding of the metal ion interaction with the resin particle. Furthermore, the role and strength of nitric acid to break the structural bonds and release the metal ions to get sorbed on the resin remains the most essential factor of understanding distribution coefficient values. Method validation parameters such as linearity, precision and accuracy of the method were determined. The method precision and accuracy were determined from the QC samples which is expressed as relative error (%RE) with the total coefficient of variation (%CV’s) were < 20%.

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25

Langford, John F. Jr. "Effects of adsorbent structure and adsorption on transport phenomena in ion-exchange chromatography". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 250 p, 2007. http://proquest.umi.com/pqdweb?did=1251904681&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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26

Ashraf-Khorassani, Medhi. "Supercritical fluid chromatography of nitrogen-containing compounds on packed columns". Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/49919.

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The separation of basic nitrogen-containing compounds has been investigated via supercritical CO₂ and 1% methanol modified CO₂. Packed columns with the following stationary phases were employed: silica, octadecyl (C₁₈), propylamino (NH₂), and polystyrene-divinyl benzene (PRP). Without modifier the range of basicities which could be eluted increased in the order of silica < PRP < C₁₈ = NH₂. Chromatographic peak shapes and selectivity were much better with propylamino column. Different aromatic amines and azaarenes were successfully separated on both analytical scale and microbore propylamino bonded phase packed columns with 100% supercritical CO₂. Separation is compared with both reversed phase and normal phase high performance liquid chromatography (HPLC). The retention mechanism study for these aromatic amines and azaarenes shows that the elution order not only depends on basicity and steric hindrance, but also on the solubility of the solute in CO₂. New cross-linked cyanopropyl and phenyl bonded phases are studied as stationary phases for packed column SFC, as well as for separation of nitrogen-containing compounds. The cross-linked bonded phase impedes access to uncapped silanol sites, thereby giving rise to better peak shapes, and more rapid elution without the necessity of a polar modifier in the mobile phase. Experiments both at elevated temperature and in the presence of methanol modifier revealed that there is no short or long term deleterious effect on the column. The separation of model mixtures of nitrated diphenylamine and nitrated anilines via SFC employing cyanopropyl packed and capillary columns is described. Peak identification and peak purity were performed by on-line Fourier transform infrared spectrometric detection. Supercritical CO₂ is employed with cyanopropyl packed columns for separation of non-polymeric components in double-base rocket propellants. Both supercritical CO₂ and CH₂Cl₂ were compared as a solvent for extraction of nonpolymeric components in "good" and "bad" double-base propellant. Finally, twenty-four phenylthiohydantion amino acids (PTH-AA) have been rapidly and efficiently separated on a cyanopropyl packed column by gradient elution of supercritical CO₂ and tetramethyl ammonium hydroxide-modified methanol. Complete or partial resolution of 22 derivatives is observed with only valine co-eluting with norleucine and lysine co-eluting with asparagine. No modifier was required for elution of neutral PTH-AA's from the cross·linked stationary phase. The addition of base plays a major role in elution of acidic and basic PTH-AA's.
Ph. D.
incomplete_metadata

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27

Reiner, George Allen. "An explosive vapor generator based on capillary gas chromatography". Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39761.

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28

Tang, Jianhua. "Development of a novel gradient chromatofocusing tandem mass spectometry technique for the determination of cationic compounds in biofluids identification of caspace 3 cleavage sites of nhe-1 by high performance liquid chromatography- mass spectrometry /". Cleveland, Ohio : Cleveland State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1247344073.

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Thesis (Ph. D.)--Cleveland State University, 2009.
Abstract. Title from PDF t.p. (viewed July 29, 2009). Includes bibliographical references (p. 105). Available online via the OhioLINK ETD Center and also available in print.

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29

Trujillo, Rebollo Andres. "ROLE OF BRILLIANT GREEN ON THE DETECTION AND SEPARATION OF NON-CHROMOPHORIC ANALYTES BY REVERSED-PHASE LIQUID CHROMATOGRAPHY (DIMERIZATION)". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275434.

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30

Ovenden, Simon P. B. "Preparation of a natural product extract library for investigation against disease states specific to defence health a mini long range research project /". Fishermans Bend Victoria : Defence Science and Technology Organisation, 2009. http://hdl.handle.net/1947/9861.

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31

Cochran, Keith Jacob. "Combined fermentation and recovery using expanded bed chromatography". Worcester, Mass. : Worcester Polytechnic Institute, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-081806-184321/.

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32

Hider, Gregg C. "High-performance liquid chromatographic analysis of commonly used drugs /". Online version of thesis, 1988. http://hdl.handle.net/1850/10693.

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Thesis (M.S.)--Rochester Institute of Technology, 1988.
Includes Addendum: High-performance liquid chromatographic analysis of commonly used drugs: Six laboratory experiments for clinical chemistry students. Includes bibliographical references (leaves 48-52).

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33

Kaplan, Muammer. "Infrared spectroscopy in supercritical fluid analysis". Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385210.

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34

Zhao, Jie. "Chromatographic analysis of active components in Semen Ziziphi Spinosae". Thesis, University of Macau, 2005. http://umaclib3.umac.mo/record=b1445365.

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35

Madichie, Chinedu Arinze. "The chromatographic analysis of organic compounds in natural waters". Thesis, University of Hull, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310270.

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36

Jennings, Claire. "Chromatographic analysis of recombinant lysostaphin expressed in Escherichia coli". Thesis, Northumbria University, 2011. http://nrl.northumbria.ac.uk/14689/.

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Lysostaphin (EC.3.4.24.75) is an extracellular glycylglycine endopeptidase produced exclusively by Staphylococcus simulans biovar staphylolyticus (ATCC 1362, NRRL B-2628). The zinc-containing endopeptidase demonstrates specific and potent staphylolytic activity therefore shows great promise for the treatment of blood-borne and biofilm-associated staphylococcal infections. The gene encoding mature lysostaphin has therefore been cloned and expressed using Escherichia coli, the most widely used expression host for recombinant protein production. Lysostaphin (EC.3.4.24.75) is an extracellular glycylglycine endopeptidase produced exclusively by Staphylococcus simulans biovar staphylolyticus (ATCC 1362, NRRL B-2628). The zinc-containing endopeptidase demonstrates specific and potent staphylolytic activity therefore shows great promise for the treatment of blood-borne and biofilm-associated staphylococcal infections. The gene encoding mature lysostaphin has therefore been cloned and expressed using Escherichia coli, the most widely used expression host for recombinant protein production. Lysostaphin (EC.3.4.24.75) is an extracellular glycylglycine endopeptidase produced exclusively by Staphylococcus simulans biovar staphylolyticus (ATCC 1362, NRRL B-2628). The zinc-containing endopeptidase demonstrates specific and potent staphylolytic activity therefore shows great promise for the treatment of blood-borne and biofilm-associated staphylococcal infections. The gene encoding mature lysostaphin has therefore been cloned and expressed using Escherichia coli, the most widely used expression host for recombinant protein production. Overall these findings are of concern for the production of recombinant protein production using E. coli. However this research suggested that chromatography can be used to sensitively detect and monitor product heterogeneity, so that a more homogeneous product could be produced by careful adjustment of expression, harvest and formulation conditions.

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37

Wentzel, Mauritz. "Identification and characterization of novel oncology related platinum complexes using chromatographic and mass spectrometric techniques". Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/715.

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In this thesis mass spectral and chromatographic techniques were developed and applied to identify and characterise numerous novel platinum(II) and (IV) compounds designed as anticancer agents. In a novel method for the synthesis of cis-oxalato(trans- -1,2- cyclohexanediamine)platinum(II) or oxaliplatin these techniques could be applied to differentiate between the molecular complex and the autoionised analogue (viz. Ptdach2 2+Ptox2 2-). In another novel synthetic method for the same compound the ligand exchange reactions at various temperatures could be investigated and kinetic curves obtained served to illuminate the chemistry involved, indicating the role of small amounts of water in the essentially non-aqueous solvent systems dmf and isoamyl alcohol respectively. These allowed ligand exchange without resulting in hydrolyses even up to 85°C. The ionisation rate of divalent platinum halide complexes was determined for various amine ligands as well as N-S chelate ligands. A comparison of these could suggest why N-S complexes have poor anticancer action. Ionisation was not only studied for neutral molecular species but also for monocationic ones. Relationships could be found with stereochemical aspects of the chelates used. By investigating results of EV-CAD studies thermodynamic data could be obtained which indicated that bond strength decreases from chloro to iodo analogues although extent of ionisation in aqueous solution, i.e kinetic stability, is the reverse. Products formed by the reaction of NO2 gas with Platinum(II) compounds could be identified and separated which greatly contributed to the understanding of the chemistry involved in the formation of mononitro platinum(IV) complexes. Some of these proved to have exceptional anticancer properties. Studies of the interaction of thiol containing biomolecules were performed as a function of time. The results contributed to the understanding of the action of the anticancer agents.

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38

Cooper, Mark Thomas. "A chromatographic method for detecting phenolic metabolites of carbosulfan in urine". Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/35977/1/35977_Cooper_1989.pdf.

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The inability of the conventional blood cholinesterase test to reliably detect carbamate pesticide poisoning in humans prompted the investigation of an alternative surveillance method. Rapid, micro-scale sample treatment procedures were developed to extract the phenolic metabolites of carbosulfan from urine, convert these compounds to their dinitrophenyl ether derivatives and determine their concentrations quantitatively by nitrogen selective gas-liquid chromatography. This method was capable of detecting micro-gram levels of metabolites and performed to an accuracy of<+/ 10% and precision of< 6% RSD. In vivo experiments we re undertaken in which carbosul fan was administered to laboratory rats and the effects of dosage and sampling time on the level of phenolic metabolites in urine were examined. These results provide guidelines for human exposure however absolute confidence in these thresholds will only occur when the data base of human experience is collected and correlated to metabolite levels in urine. Urine samples were drawn and analyzed from potentially exposed personnel handling carbosulfan and in all cases no phenolic metabolites were detected.

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39

Xie, Shunping. "Growth of silver dendrite crystals and liquid chromatographic analysis of water-soluble gold nanoclusters". HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1436.

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40

Mertzman, Melissa Danielle Foley Joe Preston. "Chiral microemulsion electrokinetic chromatography /". Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/340.

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41

Baker-Ellis, Judy. "High performance liquid chromatography analysis and quantitation of chitinolytic products of CDC group EF-4a". Virtual Press, 1985. http://liblink.bsu.edu/uhtbin/catkey/443555.

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A chitinolytic organism was cultured from a lotic habitat in central Indiana. It was isolated on the basis of its hydrolytic activity on chitin agar. It was subsequently identified as EF-4a. The chitinases of the EF-4a were isolated, purified and concentrated. A colloidal chitin suspension was then incubated with the enzyme. Samplings were taken at one minute, one hour and 24 hours. The samplings were filtered through a Swinney filtration unit and immediately after applied to a Beckman Ultrasil Amino column. It was eluted with acetonitrile: water (75:25) at a flow rate of 2 ml/min. The absorbance at 214 nm was monitored using the Beckman 160 UV detector. The chromatographs were analyzed for product elaboration. It was observed that EF-4a produced soluble, extracellular enzymes. The enzymes were a chitinase-chitobiase complex. The enzymes' action on chitin was immediate. There were varying reaction products including G1cN, GlcNAc, chitobiose, chitotriose and higher order oligomers. There was also chromatographic evidence suggesting a and B anomers of these saccharides.

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42

Kubiszewski, Jolanta. "Deconvolution of overlapped gas chromatographic peaks with EXCEL : application to three component mixtures /". View abstract, 1998. http://library.ctstateu.edu/ccsu%5Ftheses/1530.html.

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Thesis (M.S.)--Central Connecticut State University, 1998.
Thesis advisor: James V. Arena. " ... in partial fulfillment of the requirements for the degree of Master of Science in Chemistry." Includes bibliographical references (leaf 29).

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43

Buica, Astrid Sorina. "Panaceas and pitfalls in electrodriven chromatographic techniques". Thesis, Stellenbosch : University of Stellenboschv, 2007. http://hdl.handle.net/10019.1/1336.

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Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2007.
In this thesis the main capillary electrodriven chromatographic techniques (i.e. Capillary Electrochromatography CEC, Micellar Electrokinetic Chromatography MEKC and Microemulsion Electrokinetic Chromatography MEEKC) were compared in terms of column manufacturing, fundamental chromatographic performance, and some applications were developed. The first stage of this thesis aimed at developing improved packed and open tubular CEC columns. For the manufacturing of packed CEC columns, the frit-burning step proved of critical importance, together with the slow build-up of the packed bed. The making of open tubular columns is a relatively simple, "one pot" sol-gel reaction taking place in mild conditions. The nature of the gel and the resulting selectivity of the column could easily be changed by changing the precursors. In a second stage of this thesis the packed and open tubular CEC columns were evaluated chromatographically and compared with the results obtained by MEKC and MEEKC. All electrodriven separation techniques showed high efficiencies. The selectivity proved easier to tune with sol-gel chemistry for the making of open tubular columns. Resolution is acceptable for packed CEC, MEKC and MEEKC. For peak capacity, CEC has the advantage of a practically non-limited elution time, while MEKC and MEEKC suffer of the drawback of the existence of an elution window which is limited in time by the elution of the micelles. Some applications were developed in this study on open tubular CEC columns and for the packed CEC columns. Various sugars derivatized with 9- aminopyrene-1,4,6-trisulfonic acid (APTS) could be separated with open tubular CEC, using an octyl, amino or cyano stationary phase. Open tubular columns containing α, β and γ cyclodextrins attached to the stationary phase were developed. This approach proved promising for the separation of positional isomers. A method was developed for the analyses of a mixture of carbamates and for several steroids with packed column CEC directly coupled with MS.

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44

Davis, Kellie M. "Open tubular capillary electrochromatography-laser induced fluorescence for the separation and detection of proteins and amino acids". Greensboro, N.C. : University of North Carolina at Greensboro, 2007. http://libres.uncg.edu/edocs/etd/1513Davis/umi-uncg-1513.pdf.

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Thesis (M.S.)--University of North Carolina at Greensboro, 2007.
Title from PDF t.p. (viewed Mar. 11, 2008). Directed by G. Brent Dawson; submitted to the Dept. of Chemistry. Includes bibliographical references (p. 67-69).

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45

Colby, Christopher Brett. "Optimisation of scale-up of chromatography /". Title page, table of contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phc686.pdf.

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46

Motley, Curtis Bobby. "The evaluation of an argon and helium highly efficient microwave induced plasma as an element selective detector for packed column super critical fluid chromatography". Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/37740.

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47

Qian, Jianing. "Affinity chromatography of camelid antibodies". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610171.

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48

Chappell, Colin Graham. "Multidimensional liquid and gas chromatographic methods for veterinary drug analysis". Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357971.

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49

Bromilow, Ian David. "New liquid chromatographic methods for the analysis of cationic tensides". Thesis, University of Leeds, 2001. http://etheses.whiterose.ac.uk/1674/.

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Abstract (sommario):

Cationic tensides are important oleochemicals that are used to prevent adulteration of pharmaceutical preparations and personal care products, as well as being the conditioning agents in domestic fabric softeners. The widespread use of these materials requires quantitative methods for characterising them in raw materials and fully formulated products, whilst "down-the-drain" release necessitates similar methods for trace environmental analysis. Unfortunately, current methods used to quantify cationic tensides are generally non-specific, problematic, or are ill-suited to environmental analysis. There is currently no generic method that can be applied to the quantitation of these materials in all necessary matrices. The aim of this work was to develop new liquid chromatographic (LC) methods for the analysis of the cationic preservative and fabric conditioner actives, before attempting to build the foundations of generic cationic tenside analysis. The development of a new normal phase LC method is reported for the quantitation of the cationic actives present in domestic fabric conditioners. The method yielded high resolution and repeatability, and allowed the quantitation of the homologues endemic in commercial samples. Subsequent hyphenation with mass spectrometry demonstrated the potential for the quantitation of these materials in environmental matrices. -The optimisation and validation of a reverse phase LC method for the analysis of cationic tenside preservatives is reported. Excellent repeatability and resolution were again attained, whilst the new method was also found to demonstrate the inherent sensitivity required for trace environmental analysis. Subsequent hyphenation unfortunately showed that method sensitivity was compromised by ion-suppression, highlighting the need for compromise in the development of LC/MS methods. For both methods, stationary and mobile phase parameters were varied to assess the influence on analyte resolution, and also to gauge the potential for developing a generic liquid chromatographic method for the analysis of these materials. It was observed that many of the commonly held beliefs on the analysis of cationic tensides by reverse phase LC were misconceived. As a result, new insights were made into cationic tenside analysis, which should facilitate the development of a generic LC method applicable to the quantitation of cationic tensides and their hydrophilic biodegradation products in the future.

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50

Zhang, Li Qun. "Square-wave voltammetric stripping detection for flow injection analysis and chromatography". Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/26024.

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Tesi sul tema "Chromatographic analysis"

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