Articoli di riviste: "Chromatography"

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Arzu Ibragimova, Arzu Ibragimova. "BENEFITS OF USING A FID TO MEASURE THE MULTICOMPONENT GAS MIXTURES". PIRETC-Proceeding of The International Research Education & Training Centre 27, n. 06 (25 agosto 2023): 131–39. http://dx.doi.org/10.36962/piretc27062023-131.

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The development of the oil and gas complex is one of the priority areas of the Azerbaijan economy. Oil and gas are among the most competitive Azerbaijan goods and are in high and stable demand from global consumers. Therefore, increased attention is paid to product quality. One of the methods for quality control of petroleum products is gas chromatography. Today it is a widely used physical and chemical research method. The capabilities of a gas chromatography are mainly determined by the enormous separating power of the chromatographic columns and the characteristics of the detectors. If the chromatographic column is sometimes called the heart of the chromatograph, then the detector can be called the brain of the chromatograph [1,2]. Effective development of an analysis technique, its successful implementation, troubleshooting of a chromatograph, and metrological certification are impossible without the ability to make the right choice of a detector, operate it competently, and correctly interpret the detector signal. About 50 detectors have been proposed for gas chromatography, but only a few of them are used in practice. The most used are the flame ionization detector and the thermal conductivity detector. The article shows the advantage of using a flame ionization detector to measure important physical and chemical properties, such as density, caloric content, the ratio of the number of carbon atoms to the number of hydrogen atoms C/H. Keywords: Chromatography, gas-mixture, density, hydrocarbon, heat of combustion, calorific value, flame ionization detector, number of carbon atoms, sensitivity, quality.

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Tong, Daixin, Keith D. Bartle, Anthony A. Clifford e Robert E. Robinson. "Unified chromatograph for gas chromatography, supercritical fluid chromatography and micro-liquid chromatography". Analyst 120, n. 10 (1995): 2461. http://dx.doi.org/10.1039/an9952002461.

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Dolgonosov, A. M., A. G. Prudkovskii, E. A. Zaitseva, N. K. Kolotilina e A. A. Dolgonosov. "Mathematical Modelling in Analytical Chromatography: Problems and Solutions". Journal of Analytical Chemistry 76, n. 11 (novembre 2021): 1233–44. http://dx.doi.org/10.1134/s1061934821110046.

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Abstract Based on an analysis of the results of original research performed in the Laboratory of Sorption Methods of the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences within the project “Mathematical Chromatograph,” the review covers the aim and strategy of the imitation modeling of high-performance chromatography; associated problems of the theory of intermolecular interactions; classifications of polar stationary phases by their selectivity; descriptions of the kinetics and dynamics of sorption processes, choice of the composition of multicomponent mobile phases in HPLC and ion chromatography using the method of the dynamic map of a chromatographic system; and the development of alternating gradient modes using a mathematical experiment.

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Zhang, Jing, e Hongye Zhang. "Research progress on the detection of water-soluble vitamins in food using liquid chromatography". Theoretical and Natural Science 37, n. 1 (4 giugno 2024): 158–69. http://dx.doi.org/10.54254/2753-8818/37/20240183.

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Currently, liquid chromatography is widely used for the analysis and determination of water-soluble vitamins (WSVs) in functional foods. However, due to the diversity of sample characteristics and the requirement for purification accuracy, the chromatographic conditions and specific methods used vary. This paper reviews the chromatographic conditions of liquid chromatography techniques for detecting WSVs in food, as well as the selection of liquid chromatography methods in different application fields. The chromatographic conditions include chromatographic columns, column temperature, mobile phase, flow rate, and elution gradient, and the application scope of different chromatographic conditions is compared. Liquid chromatography methods include high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry, and discussions are made on the applications and prospects of these two methods under different chromatographic conditions. Therefore, this review provides research insights into different chromatographic conditions and methods for food quality inspection and biochemical analysis research.

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Ogierman, Leonard. "Gas Chromatography of Uracil Herbicides by On-Column Methylation with Trimethylanilinium Hydroxide". Journal of AOAC INTERNATIONAL 69, n. 5 (1 settembre 1986): 912–14. http://dx.doi.org/10.1093/jaoac/69.5.912.

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Abstract Substituted uracil herbicides injected into a gas chromatograph react with trimethylanilinium hydroxide to give iV-methyl derivatives with good gas chromatographic properties. Maximum methylation is obtained when the molar ratio of methylating reagent to herbicide is ca 4:1. This technique for preparing derivatives provides rapid qualitative and quantitative chromatography of the substances examined. Chromatographic response was linear with increased concentration for the synthetic standard and the on-column product of uracil herbicide. The proposed derivatization method was used to analyze herbicides in formulations. The methyl derivatives were identified spectroscopically

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ZHANG, Xin. "Chromatographic Band and Chromatographic Peak in Chromatography". University Chemistry 32, n. 9 (2017): 52–58. http://dx.doi.org/10.3866/pku.dxhx201703004.

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Denisov, I. S., V. V. Korotkov e D. S. Smirnov. "Gaschromatographic monitoring of volatile pollutants of urban air: optimizing analysis and concentrating". Sanitarnyj vrač (Sanitary Doctor), n. 10 (1 ottobre 2020): 70–76. http://dx.doi.org/10.33920/med-08-2010-08.

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For determining 22 volatile organic compounds in the atmospheric air, the operating modes of the gas chromatographic complexes «chromatography-mass spectrometer — two-stage thermodesorber» and «gas chromatograph with 2 FID — static headspace analysis sampler» are optimized. The modes provide the values of the separation coefficients of the chromatographic peaks in the range of 1.5 ÷ 21. It has been experimentally established that the highest desorption efficiency of volatile organic compounds is registered when the sample is concentrated into Tenax TA sorption tubes.

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Adel, E. Ibrahim, Elhenawee Magda, Saleh Hanaa e M. Sebaiy Mahmoud. "Overview on liquid chromatography and its greener chemistry application". Annals of Advances in Chemistry 5, n. 1 (7 aprile 2021): 004–12. http://dx.doi.org/10.29328/journal.aac.1001023.

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This literature review is concerning with liquid chromatography specifically high performance liquid chromatography (HPLC), Ultra high performance liquid chromatography (UHPLC), chromatography theory, chromatographic parameters, monolithic columns, principles of green chemistry and its application ingreen chromatography.

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Custodio-Mendoza, Jorge Antonio, Patryk Pokorski, Havva Aktaş, Alicja Napiórkowska e Marcin Andrzej Kurek. "Advances in Chromatographic Analysis of Phenolic Phytochemicals in Foods: Bridging Gaps and Exploring New Horizons". Foods 13, n. 14 (18 luglio 2024): 2268. http://dx.doi.org/10.3390/foods13142268.

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Chromatographic analysis of phenolic phytochemicals in foods has significantly advanced over the past decade (2014–2024), meeting increasing demands for precision and efficiency. This review covers both conventional and advanced chromatographic techniques used for detecting phenolic phytochemicals in foods. Conventional methods like High-Performance Liquid Chromatography, Ultra High-Performance Liquid Chromatography, Thin-Layer Chromatography, and Gas Chromatography are discussed, along with their benefits and limitations. Advanced techniques, including Hydrophilic Interaction Liquid Chromatography, Nano-LC, Multidimensional Liquid Chromatography, and Capillary Electrophoresis, are highlighted for their innovations and improved capabilities. The review addresses challenges in current chromatographic methods, emphasizing the need for standardized and validated procedures according to the Food and Drug Administration, European Cooperation for Accreditation of Laboratories, and The International Organization for Standardization guidelines to ensure reliable and reproducible results. It also considers novel strategies for reducing the environmental impact of chromatographic methods, advocating for sustainable practices in analytical chemistry.

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Meng, Xin Xin, e Shu Lin Yang. "Comparison of Gas Chromatography and Liquid Chromatogram Detecting Pesticide Residue". Applied Mechanics and Materials 539 (luglio 2014): 113–16. http://dx.doi.org/10.4028/www.scientific.net/amm.539.113.

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The existing methods of detecting pesticide residue include gas chromatography, high performance liquid chromatography, gas chromatograph-mass, liquid chromatograph-mass, capillary electrophoresis, radioimmunoassay, biosensor and rapid detection on the spot. The paper analyzes the comparison of gas chromatography and liquid chromatogram detecting pesticide residue, for achieving the development tendency and the future goal of analyzing pesticide residue.

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Peterson, Robert E., Gail M. Shannon e Odette L. Shotwell. "Purification of Cyclopiazonic Acid by Liquid Chromatography". Journal of AOAC INTERNATIONAL 72, n. 2 (1 marzo 1989): 332–35. http://dx.doi.org/10.1093/jaoac/72.2.332.

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Abstract A purification procedure for cyclopiazonic acid has been developed, using sequential preparative and semi-preparative liquid chromatography. Crude cyclopiazonic acid (324 mg) was extracted from a 1 L fermentation medium with chloroform-methanol (80 + 20), dried, dissolved in chloroform, and chromatographed on an oxalic acid/ silica preparative column with chloroform-methanol (99 + 1) as the eluant. A semi-preparative oxalic acid/silica column and chloroform- methanol (99.5 + 0.5) were then used for rechromatography of the partially purified cyclopiazonic acid. This second chromatographic treatment yielded fractions from which cyclopiazonic acid was readily crystallized (106.7 mg; 33% recovery). Analytical chromatography was developed using an amino column in an ion-exchange mode, with a methanol-phosphate buffer eluant. Response was linear from 10 to 800 μg/injection of standard solutions. Cyclopiazonic acid chemically binds sodium from soda-lime vials.

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Omelchuk, Sergii T., Alina I. Syrota e Anna V. Blagaia. "THE NEED FOR IMPROVEMENT OF FUNGICIDES RESIDUAL QUANTITIES CONTROL METHODS IN THE CONDITIONS OF THE DOMESTIC REGULATORY BASE HARMONIZATION". Wiadomości Lekarskie 75, n. 10 (2022): 2455–61. http://dx.doi.org/10.36740/wlek202210126.

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The aim: To develop highly sensitive analytical methods for the determination of the systemic phenylamide class fungicide – Metalaxyl-M residues in watermelons and grapes to reduce the risk of hazardous effects on workers’ and public health. Materials and methods: Conditions for Metalaxyl-M detection by gas-liquid chromatography (GLC) using a chromatographic capillary column SH-Rxi-5ms (length – 30 m, inner diameter – 0.25 mm, layer thickness – 0.25 μm) were determined. The optimal conditions for chromatography of Metalaxyl-M were established: column thermostat temperature – 220°С, evaporator temperature – 260 °С, detector temperature – 280 °С. The retention time under these conditions was 3,384 ± 0.1 minutes. The linear detection range is 0.01 to 0.05 mg / kg. The calibration dependence of the tested substance peak area on its concentration was established and described by the linear regression equation. Results: We found that the most sensitive method for chromatography of Metalaxyl-M is the method of using a capillary column SH-Rxi-5ms on a gas chromatograph Shimadzu Nexis 2030. Conclusions: The developed GC methods correspond to modern requirements, are selective and allow to control the Metalaxyl-M content in the matrices of the studied crops and can be used as a marker of the safety of agricultural products grown with fungicides containing Metalaxyl-M application. We found that the most sensitive method for Metalaxyl-M chromatography detection is the method with usage of a capillary column SH-Rxi-5ms on a gas chromatograph Shimadzu Nexis 2030.

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Hammack, Walter, Mary C. Carson, Barbara K. Neuhaus, Jeffrey A. Hurlbut, Cristina Nochetto, James S. Stuart, Amy Brown et al. "Multilaboratory Validation of a Method To Confirm Chloramphenicol in Shrimp and Crabmeat by Liquid Chromatography-Tandem Mass Spectrometry". Journal of AOAC INTERNATIONAL 86, n. 6 (1 novembre 2003): 1135–43. http://dx.doi.org/10.1093/jaoac/86.6.1135.

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Abstract An existing method for chloramphenicol (CAP) determination in shrimp using a gas chromatograph with electron capture detector was adapted for confirmation of CAP with a liquid chromatograph interfaced to a triple quadrupole mass spectrometer. CAP residues are extracted from tissue with ethyl acetate, isolated via liquid–liquid extraction, and concentrated by evaporation. Extracts are chromatographed by using a reversed-phased column and analyzed by electrospray negative mode tandem mass spectrometry. Four product ions (m/z 152, 176, 194, and 257) of precursor m/z 321 were monitored. Moving from gas chromatography to liquid chromatography–tandem mass spectrometry improved the sensitivity of the method greatly, enabling reliable confirmation of CAP residues at 0.3 μg/kg (ppb). The method meets confirmation criteria recommended by the U.S. Food and Drug Administration and 4-point identification criteria established by the European Union. With slight modifications to accommodate different equipment, the method was validated in 3 laboratories.

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Zui, O. "Development of ion chromatography in Ukraine." Zurnal Hromatograficnogo tovaristva 21, n. 67 (4 settembre 2021): 39–45. http://dx.doi.org/10.15407/zht2021.67.039.

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The ways of development of ion chromatography in Ukraine from the eighties of the last century to the present time are shown. The achievements of research institutes, in particular, the Dumansky Institute of Colloid Chemistry and Water Chemistry of the National Academy of Sciences of Ukraine, in the development of ion chromatographic methods for the analysis of organic and inorganic anions in various objects, including natural and drinking waters, are highlighted. Scientists of Ukraine (A.T. Pilipenko, O.V. Zuy, A.V. Terletskaya) compared commercially available sorbents for ion chromatography – HIKS-1, ANIEKS-N and KANK ASt for their use in water analysis. The studies were carried out on an ion chromatograph "Tsvet-3006" with a conductometric detector. It has been shown that ANIEKS-N with a borate eluent is the best sorbent for the determination of organic monocarboxylic acid ions, and KANK ASt with a carbonate-hydrocarbonate eluent – for the determination of inorganic anions. Ion chromatography has been used to solve a number of practical problems: for the separation of oxoanions  iodate, chlorate and bromate in waters, to control the results in the development of chemiluminescent methods for the determination of chloride, nitrite and nitrate, to establish the mechanism of destruction of anionic surfactants under the action of vacuum ultraviolet radiation and corona discharge. The method was applied to the analysis of iodine-containing bottled waters for bromide ions due to the absence of the interference from iodides. The accumulated experience has contributed to the adoption in Ukraine of four state standards for water quality, based on the use of the ion chromatographic method. It is shown that the method of ion chromatography at the present stage is widely used in various sectors of the national economy: to determine the traces of anions in steam condensate of power plants, to control the anionic composition of water at nuclear power plants, to correct water treatment processes at waterworks, in particular, when analyzing chlorite ions in tap water obtained with the use of chlorine dioxide as a disinfectant.

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Orlenko, Dmytro, Volodymyr Yakovenko, Vyacheslav Plastun e Liliia Vyshnevska. "DEVELOPMENT AND VALIDATION OF METHODS FOR QUANTITATIVE DETERMINATION OF SODIUM HYALURONATE IN THE COMPOSITION OF COMBINED DENTAL GEL". EUREKA: Health Sciences 5 (30 settembre 2020): 72–81. http://dx.doi.org/10.21303/2504-5679.2020.001420.

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According to the EP monograph "Sodium hyaluronate" for identification they use the infrared transmission spectrum of the substance, quantification is carried out by spectrophotometry. The aim of the work was to develop a method for quantitative determination of hyaluronic acid in the gel in the presence of other substances and its validation. Materials and Methods. The object of the study were samples of combined dental gel of the following composition: metronidazole benzoate 16 mg/g, miramistin 5 mg / g, sodium hyaluronate 2 mg / g. Identification and quantification of sodium hyaluronate was performed by liquid chromatography (SPhU, 2.2.29, 2.2.46). The test solution and the reference solution were chromatographed, obtaining the number of parallel chromatograms not less than when checking the suitability of the chromatographic system. Chromatography is performed on a liquid chromatograph with a diode-matrix detector under the following conditions: chromatographic column PL-aquagel-OH, Agilent size 300 mm × 7.5 mm, with a particle size of sorbent 8 μm; mobile phase A: 0.1 M sodium sulfate solution; mobile phase B: acetonitrile for chromatography P; detection at a wavelength of 210 nm. Results. The retention time of sodium hyaluronate on the chromatogram of the test sample of the gel coincides with the peak and the retention time on the chromatogram of the comparison solution of the standard sample of the substance. The suitability of the chromatographic system for 3 parallel determinations was checked: the relative standard deviation (RSD) is equal to 0.25, the number of theoretical plates is 980, the symmetry coefficient is 1.293. The validation characteristics of the developed methodology meet the established eligibility criteria. The spectral purity coefficients (Fp) of the sodium hyaluronate peak on the chromatograms of the model solution are Fp1=997.665 and Fp2=997,802. The method is linear in the range of sodium concentration of hyaluronate 80–120 %, the calculated linear dependence of the reduced area of the chromatographic peak on the reduced concentration of sodium hyaluronate is |a|=1.9490≤Δa=2.56. The confidence interval of the unit value for the sample of relations is found / entered Δz=1.08, which corresponds to the condition Δz≤1.6 %. The value of the systematic error is equal to δ=0.12, which satisfies the condition δ≤0.51 %. Conclusions. The method of quantitative determination of sodium hyaluronate by the method of high-performance liquid chromatography has been developed and investigated. The method allows the identification and quantification of sodium hyaluronate in the composition of the dental gel, in the presence of metronidazole benzoate and miramistin. Validation of the methodology was performed and the main validation characteristics were determined. In terms of specificity, linearity, correctness, convergence of the method meets the eligibility criteria established by the SPhU.

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Kataev, S. S., O. N. Dvorskaya, M. A. Gofenberg, A. V. Labutin e A. B. Melentyev. "ANALYTICAL FEATURES OF SYNTHETIC MDMB(N)-073F CANNABIMIMETICS AND ITS MARKERS IN BIOLOGICAL MATERIAL". Pharmacy & Pharmacology 7, n. 4 (10 settembre 2019): 184–97. http://dx.doi.org/10.19163/2307-9266-2019-7-4-184-197.

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The aim of the research is to study both analytical features of synthetic MDMB(N)-073F cannabimimetics of indazole carboxamides group by gas chromatography methods combined with tandem mass spectrometry (GC-MS) and high performance liquid chromatography with high-resolution mass spectrometry (HPLC-HRMS) as well as characteristics of the major MDMB(N)-073F metabolite, its glucuronide and derivatives, using gas chromatography with mass-spectrometric (GC-MS) detection and high-performance liquid chromatography (HPLC) with MS/MS mass spectrometry (HPLC-MS/MS) in urine samples to be applied in expert practice, chemical-toxicological and forensic and chemical analyses.Materials and methods. To carry out the study, the following materials were used: plant-based objects with narcotic drugs withdrawn from illegal trafficking and applied to them;. urine samples to be studied under chemical-toxicological and forensic and chemical analyses. For solid-phase epitaxy, SampliQ EVIDEX TFE cartridges – 200 mg – 3 ml (Agilent, USA) were used for sample preparation; β-glucuronidase, Type HP-2, From Helix Pomatia, 100000 UA/ml (Sigma-ALDRICH CHEMI, Germany) was used for enzymatic hydrolysis. GC-MS/MS analysis was made using Agilent 7890 gas chromatograph with a tandem quadrupolar mass-spectrometer Agilent 7000 (Agilent, США); GC-MS analysis was carrid out using gas chromatograph Agilent 7820 with mass-selective detector Agilent 5975 (Agilent, USA); HPLC-HRMS research was made on liquid chromatograph Agilent 1260 with tandem hybrid high-resolution quadrupole-time-of-flight detector Agilent 6540 (Agilent, США); liquid chromatograph Agilent 1260 with Agilent 6460 (Agilent, USA) with tandem mass-spectrometer were used for making HPLC-MS/MS research.Results. The structure of MDMB(N)-073F compound has been confirmed and an exact mass of the protonated molecule corresponding to the chemical formula C19H27FN3O3 fixed by GC-MS/MS and HPLC-HRMS methods. Spectral characteristics of MDMB(N)-073F have been given. One of the branches in MDMB(N)-073F biotransformation in the human body found out by GC-MS and HPLC-MS/MS methods, is the ester decomposition with further conjugation of the resulting acid. The product interacting with glucuronic acid, is found to be the conjugate of major MDMB(N)-073F metabolite of the Ist phase in biotransformation. Metabolites appearing due to the ester decomposition and its conjugate with glucuronic acid, are recommended to be used as markers for synthetic MDMB(N)-073F cannabimimetics in the analysis by chromatographic methods; they can be used for regular screening of biological samples.Conclusion. The research results presented here, are the following: the analytical features characteristic for synthetic MDMB(N)-073F cannabimimetics found out by gas chromatography methods combined with tandem mass spectrometry (GC-MS/ MS) and liquid chromatography of hybrid high-resolution quadrupole-time-of-flight mass spectrometry (HPLC-HRMS), as well as characteristics of major MDMB(N)-073F metabolite, its glucuronide and derivatives with the use of gas chromatography with mass-spectrometric detection (GC-MS) and liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS) in urine samples to be applied in expert practice, chemical-toxicological, forensic and chemical analyses.

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Christopoulou, C. N., e E. G. Perkins. "Chromatographic studies on fatty acid dinners: Gas-liquid chromatography, high performance liquid chromatography and thin-layer chromatography". Journal of the American Oil Chemists' Society 66, n. 9 (settembre 1989): 1353–59. http://dx.doi.org/10.1007/bf03022761.

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Gertsiuk, Modest. "Chromatography in Ukraine: Development and Achievements". Separations 9, n. 5 (3 maggio 2022): 114. http://dx.doi.org/10.3390/separations9050114.

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The development of chromatographic science in Ukraine is due to the widespread use of chromatography to solve practical problems. The centers of chromatographic research in Ukraine are in large cities: Kyiv, Kharkiv, Lviv, Odessa, and others. Along with the development of chromatographic research methods, analysis methods for control of food and agricultural raw materials, medicinal products, petroleum products, and determination of the environmental pollution state are created. Chromatography is used in medicine, pharmacology, biology, and other sciences.

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Hill, Derek A., Paul Mace e Donald Moore. "Frontal chromatographic techniques in preparative chromatography". Journal of Chromatography A 523 (dicembre 1990): 11–21. http://dx.doi.org/10.1016/0021-9673(90)85007-i.

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Tsarev, V. N., N. G. Bazarnova e I. V. Mikushina. "Development of a Preparative Method for Obtaining an Enantiomerically Pure Substance of Salbutamol by Supercritical Fluid Chromatography". Drug development & registration 11, n. 4 (27 novembre 2022): 160–69. http://dx.doi.org/10.33380/2305-2066-2022-11-4-160-169.

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Introduction. An increasing number of studies conducted in various countries in the field of biopharmacy convincingly show the differences in the physiological effects on the human body of stereoisomers of pharmaceutical substances. As a rule, one of the enantiomers has the necessary pharmacological effect, the other enantiomer is either inert or has a negative side effect. Currently, it is important to obtain enantiomerically pure pharmacological substances from their racemic mixtures.Aim. Obtaining the R-isomer of salbutamol from a racemic mixture of salbutamol and developing a preparative procedure for chiral separation by supercritical fluid chromatography (SFC) with a yield of the target product sufficient for the production process.Materials and Methods. Supercritical fluid chromatography (SFC) is widely used for analytical and preparative separations of enantiomers of pharmaceutical substances. The relevance of the use of supercritical fluid chromatography SFC is largely due to the fact that it uses sub- or supercritical carbon dioxide (SC-CO2) as the main component of the mobile phase (MP). Studies were carried out on semi-preparative Investigator SFC (Waters Corporation, USA) and preparative Prep 200 qSFC (Waters Corporation, USA) supercritical fluid chromatographs with PDA detectors. Samples were weighed to the nearest 0.0001 g on a XPE206DR balance (Mettler Toledo, USA).Results and discussion. The process of chiral separation of salbutamol sulfate by the SFC method on Prep 200 qSFC (Waters Corporation, USA) was studied. It was revealed that in the chromatographic system under supercritical conditions, the salt is separated into acidic and basic residues, which significantly reduces productivity and shortens the duration of continuous operation of the chromatograph. Conditions for the preparative chiral separation of the racemic mixture of salbutamol base into R- and S-isomers with high enantioselectivity and productivity have been developed. The resulting R-isomer of salbutamol base can be converted into the pharmaceutical substance in the form of sulfate or other salt without loss of enantiomeric purity, the S-isomer can be subjected to racemization and subsequent use.Conclusion. A preparative method has been developed for the chiral separation of a racemic mixture of salbutamol by supercritical fluid chromatography (SFC) with a yield of the target product (R-isomer) of 5.5 g per shift (8 hours).

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Chen, Yi, Cong Ming Zou, Jun Bin, Min Yang e Chao Kang. "Multilinear Mathematical Separation in Chromatography". Separations 8, n. 3 (13 marzo 2021): 31. http://dx.doi.org/10.3390/separations8030031.

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Chromatography is a powerful and generally applicable method for the analytical separation and quantification of the chemical constituents in complex mixtures because chromatographic separation can provide high selectivity by isolating all analytes from interferences. Multiway analysis based on the multilinear model is an increasingly widely used method for interference-free and fast determination of the chemical constituents also in complex mixtures because multilinear mathematical separation can provide high selectivity by extracting the pure signal of the analyte from the mixed signal of a real sample. By combining chromatographic separation with mathematical separation, multiway calibration method, multiway standard additions method, and multiway internal standard method can be established. Chromatography assisted by multiway analysis can reduce the requirements for complete chromatographic separation, save elution time, and decrease the consumption of the mobile phase, particularly when the peak coelution problem is difficult to solve. This review presents the fundamentals and analytical applications of multilinear mathematical separation in chromatography.

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Durai Ananda Kumar T, Sai Charan, Venkateswarlu A e Supriya Reddy K. "Evolution of liquid chromatography: Technologies and applications". International Journal of Research in Pharmaceutical Sciences 11, n. 3 (8 luglio 2020): 3204–11. http://dx.doi.org/10.26452/ijrps.v11i3.2449.

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Liquid chromatographic offers efficient analyte separation employing high pressure pumps. The reversed phase high performance liquid chromatography (RP-HPLC) is widely utilized in the purity testing and quantitative determination of pharmaceuticals and neutraceuticals. The limitations of traditional liquid chromatography such as particle size, resolution and selectivity demanded for the developments and Waters Corporation developed ultraperformance liquid chromatography (UPLC). Ultrafast liquid chromatography (UFLC) is another milestone, which offers faster and efficient separation. Multidimensional UHPLC provides separation of complex molecules. The particle size decrease enhances the resolution of LC separation. Ethylene bridged hybrid (BEH), Charged surface hybrid (CSH) and Peptide separation technology (PST) offer better performance in. The amalgamation of chromatographic and spectroscopic detectors namely fluorescence detector (FD) and mass spectrometry (MS) provides efficient separation. Liquid chromatography (LC) offers the analysis of pharmaceuticals, biological, food materials, and natural products. This review covers technologies and recent pharmaceutical and biomedical applications of liquid chromatography technologies

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Knowles, David E., Bruce E. Richter, Michele B. Wygant, Lori Nixon e Marion R. Andersen. "Supercritical Fluid Chromatography: A New Technique for AOAC". Journal of AOAC INTERNATIONAL 71, n. 3 (1 maggio 1988): 451–57. http://dx.doi.org/10.1093/jaoac/71.3.451.

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Abstract Supercritical fluid chromatography (SFC) is a chromatographic technique that, in many ways, is a hybrid of gas chromatography and liquid chromatography and offers many advantages over both. As this technique continues to grow in use, SFC will become very advantageous to the AOAC analyst.

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Kord, Alireza S., e Morteza G. Khaledi. "Chromatographic characteristics of surfactant-mediated separations: micellar liquid chromatography vs ion pair chromatography". Analytical Chemistry 64, n. 17 (settembre 1992): 1901–7. http://dx.doi.org/10.1021/ac00041a027.

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Zimenkina, Natalya I., e Vladimir A. Kurkin. "Tincture of <i>Juglans nigra</i> L. bark: peculiarities of standardization". Aspirantskiy Vestnik Povolzhiya 21, n. 5-6 (15 maggio 2021): 36–47. http://dx.doi.org/10.55531/2072-2354.2021.21.3.36-47.

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BACKGROUND: Juglans nigra L. is a species of trees in the Juglandaceae family. This plant of the genus Juglans L. has not been sufficiently studied in comparison with other species, including Juglans regia L. It is a perspective medicinal plant raw material, its derivatives have an antimicrobial, general tonic effect. The known antimicrobial and general tonic activity of Juglans L preparations presented on the pharmaceutical market is probably due to substances of a flavonoid nature. These data indicate the relevance of studying the flavonoids of the Juglans nigra L. bark. AIM: The aim of this study is to develop methods for qualitative analysis and quantitative determination of biologically active compounds for tincture of Juglans nigra L. bark with the using of spectrophotometry, thin layer chromatography, microcolumn high performance liquid chromatography. MATERIALS AND METHODS: The object of the study was the tincture of Juglans nigra L. bark, samples of which were prepared in March-April 2020 on the territory of the Botanical Garden of Samara University, standard samples of myricitrin, myricetin. UV spectra were recorded with the use of Specord 40 spectrophotometer (Analytik Jena). Chromatographic analysis was carried out by thin-layer chromatography (qualitative analysis), reversed-phase high performance liquid chromatography on a Milikhrom-6 microcolumn liquid chromatograph (quantitative analysis). RESULTS: As a result of the chromatographic study, myricitrin were revealed, it appeared to be the dominant flavonoid substance. This compound has Rf value of about 0.4 in the solvent system of chloroform-ethanol-water (25:18:2). A method for the quantitative determination of the total flavonoids calculated on myricitrin in tincture of Juglans nigra L. bark was developed by means of differential spectrophotometry. It was determined that the content of the total flavonoids calculated on myricitrin in the tincture of Juglans nigra L. bark was 0.84 0.07%. A method for the quantitative determination of myricitrin in tincture of Juglans nigra L. bark by high performance liquid chromatography was developed. The content of the dominant flavonoid as myricitrin (myricetin-3-O--L-rhamnopyranoside) in the tincture of Juglans nigra L. bark was 0.42 0.06%. CONCLUSIONS: The methods of qualitative analysis and quantitative determination of flavonoids for tincture of Juglans nigra L. bark with the use of modern instrumental methods of analysis (spectrophotometry, thin layer chromatography, high performance liquid chromatography) has been developed. These results can be used to standardize the tincture of Juglans nigra L. bark.

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Rudakova, Olha, Svitlana Gubar, Nataliia Smielova, Maksym Yaremenko, Nataliia Bevz e Victoriya Georgiyants. "Development of a unified approach to the method of identification, quantitative determination of active substances and accompanying impurities in a combined drug by HPLC method". ScienceRise: Pharmaceutical Science, n. 2(36) (29 aprile 2022): 81–89. http://dx.doi.org/10.15587/2519-4852.2022.255851.

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The aim of the work is to develop a method of identification, quantification of acetylsalicylic and ascorbic acids in the combined presence and concomitant impurities in the combined drug in the form of effervescent powder for preparation of oral solution by liquid chromatography and study of validation characteristics. Materials and methods. ProStar liquid chromatograph with “Varian” spectrophotometric detector. Chromatographic column with a size of 150×4.6 mm, filled with aminopropylsilyl silica gel for chromatography (Supelcosil LC-NH2, “Supelco”) with a precolumn (particle size 3 μm), mobile phase - buffer solution pH 3.2 - acetonitrile P (80:20), elution mode – isocratic; mobile phase velocity – 1.2 ml/min; the detection wavelength is 240 nm. Results. To determine acetylsalicylic and ascorbic acids by high-performance liquid chromatography with UV detection, the optimal chromatographic conditions were selected considering the influence of other active and excipients in the drug. To prove the possibility of applying the proposed technique in the subsequent analysis of the effervescent powder, its validation was performed. The obtained validation characteristics indicate that the method of quantitative determination of acetylsalicylic acid in the studied dosage form corresponds to the parameters: accuracy, precision, linearity ( =0.92≤max =1.60, d=0.19≤maxd=0.51, a=0.17 max a=2.60, r=0.9994 min r=0.9981). In the quantitative determination of ascorbic acid in the combined effervescent powder it is established that the correctness, precision, linearity are performed ( =0.86≤max =1.60, d=0.02≤max d=0.51, a=1.99 max a=2.60, r=0.9997 min r=0.9981). Conclusions. A new method for the identification, quantification of acetylsalicylic and ascorbic acids in the combined presence and concomitant impurities in the effervescent powder using high performance liquid chromatography has been developed. The validation of the proposed method is carried out and its acceptability for use in pharmaceutical analysis is proved

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El Deeb, Sami. "Enhancing Sustainable Analytical Chemistry in Liquid Chromatography: Guideline for Transferring Classical High-Performance Liquid Chromatography and Ultra-High-Pressure Liquid Chromatography Methods into Greener, Bluer, and Whiter Methods". Molecules 29, n. 13 (5 luglio 2024): 3205. http://dx.doi.org/10.3390/molecules29133205.

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This review is dedicated to sustainable practices in liquid chromatography. HPLC and UHPLC methods contribute significantly to routine analytical techniques. Therefore, the transfer of classical liquid chromatographic methods into sustainable ones is of utmost importance in moving toward sustainable development goals. Among other principles to render a liquid chromatographic method green, the substitution of the organic solvent component in the mobile phase with a greener one received great attention. This review concentrates on choosing the best alternative green organic solvent to replace the classical solvent in the mobile phase for easy, rapid transfer to a more sustainable normal phase or reversed-phase liquid chromatography. The main focus of this review will be on describing the transfer of non-green to green and white chromatographic methods in an effort to elevate sustainability best practices in analytical chemistry. The greenness properties and greenness ranking, in addition to the chromatographic suitability of seventeen organic solvents for liquid chromatography, are mentioned to have a clear insight into the issue of rapidly choosing the appropriate solvent to transfer a classical HPLC or UHPLC method into a more sustainable one. A simple guide is proposed for making the liquid chromatographic method more sustainable.

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Sandesh, J. Srikanth Sandesh, Shyamala, Kurva Swapana, Sirra Balaiah e J. V. C. Sharma. "A REVIEW ON FLASH CHROMATOGRAPHY AND ITS PHARMACEUTICAL APPLICATIONS". Journal of Biomedical and Pharmaceutical Research 10, n. 1 (17 marzo 2021): 120–24. http://dx.doi.org/10.32553/jbpr.v10i1.850.

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Earlier column chromatography was used for preparative purposes as well as for reaction control in organic synthesis. Column chromatography is an extremely tedious stage in any laboratory and can quickly become a point of congestion for any process lab. Flash chromatography is a technique developed as a modification of preparative column chromatography. This is an air pressure driven technique comprising of medium and short column chromatography, optimised for rapid separation of organic compounds. Modern flash chromatographic system consists of pre- packed plastic cartridges where in the solvent is pumped through the cartridge. By employing high pressure gas, the efficiency and speed of classical column chromatography can be increased. Flash chromatography is an easy & quick approach that is economical to preparative liquid chromatography. The content mentioned in this article mainly focuses on the various components, general principles, procedures and applications of flash chromatography.

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Memon, Najma, Tahira Qureshi, Muhammad Iqbal Bhanger e Muhammad Imran Malik. "Recent Trends in Fast Liquid Chromatography for Pharmaceutical Analysis". Current Analytical Chemistry 15, n. 4 (3 luglio 2019): 349–72. http://dx.doi.org/10.2174/1573411014666180912125155.

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Background: Liquid chromatography is the workhorse of analytical laboratories of pharmaceutical companies for analysis of bulk drug materials, intermediates, drug products, impurities and degradation products. This efficient technique is impeded by its long and tedious analysis procedures. Continuous efforts of scientists to reduce the analysis time resulted in the development of three different approaches namely, HTLC, chromatography using monolithic columns and UHPLC. Methods: Modern column technology and advances in chromatographic stationary phase including silica-based monolithic columns and reduction in particle and column size (UHPLC) have not only revolutionized the separation power of chromatographic analysis but also have remarkably reduced the analysis time. Automated ultra high-performance chromatographic systems equipped with state-ofthe- art software and detection systems have now spawned a new field of analysis, termed as Fast Liquid Chromatography (FLC). The chromatographic approaches that can be included in FLC are hightemperature liquid chromatography, chromatography using monolithic column, and ultrahigh performance liquid chromatography. Results: This review summarizes the progress of FLC in pharmaceutical analysis during the period from year 2008 to 2017 focusing on detecting pharmaceutical drugs in various matrices, characterizing active compounds of natural products, and drug metabolites. High temperature, change in the mobile phase, use of monolithic columns, new non-porous, semi-porous and fully porous reduced particle size of/less than 3μm packed columns technology with high-pressure pumps have been extensively studied and successively applied to real samples. These factors revolutionized the fast high-performance separations. Conclusion: Taking into account the recent development in fast liquid chromatography approaches, future trends can be clearly predicated. UHPLC must be the most popular approach followed by the use of monolithic columns. Use of high temperatures during analysis is not a feasible approach especially for pharmaceutical analysis due to thermosensitive nature of analytes.

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Saake, B., S. Lebioda e J. Puls. "Analysis of the substituent distribution along the chain of water-soluble methyl cellulose by combination of enzymatic and chemical methods". Holzforschung 58, n. 1 (5 febbraio 2004): 97–104. http://dx.doi.org/10.1515/hf.2004.013.

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Abstract Four methyl cellulose samples in the degree of substitution range from 0.5 to 2.0 were characterised by combination of different analytical methods. Samples were analysed regarding their partial degree of substitution by hydrolysis and anion exchange chromatography with pulsed amperometric detection. For calibration of the chromatographic system, standard substances were isolated by preparative HPLC and their structure was confirmed by 13C-NMR spectroscopy. For two methyl cellulose samples per-acetylation and 13C-NMR with inverse gated decoupling was carried out for comparison with the chromatographic analysis. Endoglucanase fragmentation of methyl celluloses was performed and water-soluble and insoluble fractions were analysed separately. A preparative size exclusion chromatography system for enzymatic-degraded water-soluble methyl cellulose was developed and the molar masses of the individual fractions were examined by analytical size exclusion chromatography. By combination of endoglucanase fragmentation, preparative chromatography, hydrolysis and anion exchange chromatography an approach for the analysis of the substitutent distribution along the polymeric chain of water-soluble methyl cellulose could be established.

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Tarter, J. G., e P. J. Worsfold. "Ion chromatography (chromatographic science series, vol. 37)". Analytica Chimica Acta 207 (1988): 381. http://dx.doi.org/10.1016/s0003-2670(00)80823-5.

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Helfferich, FriedrichG. "Complexation chromatography (Chromatographic Science Series, Vol. 57)". Journal of Chromatography A 626, n. 2 (dicembre 1992): 317–18. http://dx.doi.org/10.1016/0021-9673(92)85429-w.

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Naida, O. O., B. A. Rudenko, R. Kh Khamizov e M. A. Kumakhov. "Polycapillary (multichannel) chromatographic columns in liquid chromatography". Journal of Analytical Chemistry 64, n. 7 (30 giugno 2009): 721–24. http://dx.doi.org/10.1134/s1061934809070107.

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Tsecheev, Arthur T., e Yurii N. Karpenko. "Application of UV spectrophotometry and reversed-phase HPLC to determine the ionization constant of a new biologically active compound". Aspirantskiy Vestnik Povolzhiya 23, n. 2 (16 giugno 2023): 60–65. http://dx.doi.org/10.55531/2072-2354.2023.23.2.60-65.

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Aim to determine the ionization constant (pKa) of the biologically active compound 2-ABPPC by UV spectrophotometry and high performance liquid chromatography (HPLC). Material and methods. The object of the study was the substance 2-ABPPC (2-amino-1-(4-bromophenyl)-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-4,5-dihydro-1H-pyrrole-3- carboxamide). The methods of UV spectrophotometry and high performance liquid chromatography were used to determine the ionization constant. The spectrophotometric analysis was carried out on a Shimadzu UV-1800 spectrophotometer. The chromatographic determination of the pKa value was carried out on an LC-20 Prominence liquid chromatograph (Shimadzu) using a Zorbax Extend-C18 reversed-phase column. Results. In the course of study, it was found that 2-ABPPC has one pKa value. When using two different methods to estimate the ionization constant, the comparable results were obtained: 7.64 (UV spectrophotometry method) and 7.40 (reversed phase HPLC method).

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Eliashvili, Levan. "Quantification of Glucose and Fructose in Georgian Semi-sweet Wines". Works of Georgian Technical University, n. 2(532) (10 giugno 2024): 11–14. http://dx.doi.org/10.36073/1512-0996-2024-2-11-14.

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One of the important parameters for wine certification is the quantitative determination of glucose and fructose, for which the highly efficient liquid chromatographic method is tested and is accurate. The quantitative determination of glucose and fructose in semi-sweet wines using high performance liquid chromatography is discussed in the article. A high-performance liquid chromatograph (HPLC) with a refractive index detector (RID) and a reversed-phase alkali amine chromatography column was used during the analysis. The method showed a high correlation coefficient during calibration (R2 = 0.99). With the given method, the concentration of glucose and fructose in semi-sweet wines of some denominations of Georgian production was measured. Quantification of these sugars is of particular importance in assessing the sweetness profile of wine and ensuring compliance with quality standards. For analysis, semi-sweet wines of Georgian production were used, in which the total amount of glucose and fructose is within the norm according to the Georgian Government Resolution #524.

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Grob, Konrad, e Zhangwan Li. "Damage to gas chromatographic columns caused by peroxides in liquid chromatographic eluents for coupled liquid chromatography-gas chromatography". Journal of Chromatography A 455 (gennaio 1988): 297–300. http://dx.doi.org/10.1016/s0021-9673(01)82128-2.

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37

Kortmann, Carlotta, Taieb Habib, Christopher Heuer, Dörte Solle e Janina Bahnemann. "A Novel 3D-Printed and Miniaturized Periodic Counter Current Chromatography System for Continuous Purification of Monoclonal Antibodies". Micromachines 15, n. 3 (13 marzo 2024): 382. http://dx.doi.org/10.3390/mi15030382.

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Continuous chromatography has emerged as one of the most attractive methods for protein purification. Establishing such systems involves installing several chromatographic units in series to enable continuous separation processes and reduce the cost of the production of expensive proteins and biopharmaceuticals (such as monoclonal antibodies). However, most of the established systems are bulky and plagued by high dead volume, which requires further optimization for improved separation procedures. In this article, we present a miniaturized periodic counter-current chromatography (PCCC) system, which is characterized by substantially reduced dead volume when compared to traditional chromatography setups. The PCCC device was fabricated by 3D printing, allowing for flexible design adjustments and rapid prototyping, and has great potential to be used for the screening of optimized chromatography conditions and protocols. The functionality of the 3D-printed device was demonstrated with respect to the capture and polishing steps during a monoclonal antibody purification process. Furthermore, this novel miniaturized system was successfully used for two different chromatography techniques (affinity and ion-exchange chromatography) and two different types of chromatographic units (columns and membrane adsorbers). This demonstrated versability underscores the flexibility of this kind of system and its potential for utilization in various chromatography applications, such as direct product capture from perfusion cell cultures.

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Bertuzzi, Terenzio, Silvia Rastelli, Annalisa Mulazzi e Amedeo Pietri. "LC-MS/MS and LC-UV Determination of Moniliformin by Adding Lanthanide Ions to the Mobile Phase". Toxins 11, n. 10 (29 settembre 2019): 570. http://dx.doi.org/10.3390/toxins11100570.

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An innovative chromatographic analysis was developed for the determination of moniliformin (MON). Because of its ionic nature, MON is weakly retained in reversed-phase chromatography and the separation may be tricky. Nevertheless, this technique is normally used either with the formation of ion pairs or employing specific RP columns for polar compounds, or combining anion exchange and hydrophobic interactions. Hydrophilic interaction chromatography (HILIC) was also used, but a non-negligible peak tailing was observed. Besides its ionic nature, MON is a di-ketone and di-ketones, mainly β-di-ketones, can easily form complexes with lanthanide ions. Then, in this work the addition of lanthanide ions to the mobile phase was investigated, aiming at improving peak shape and MON separation. La3+, Tb3+ or Eu3+ aqueous solutions were used as mobile phase and MON was chromatographed using a LC-NH2 column. The probable formation of coordination complexes lanthanide-MON in the HPLC mobile phase allowed to obtain a symmetrical peak shape and a satisfactory chromatographic separation by both mass spectrometry (MS/MS) and UV detection. Finally, a suitable extraction and purification method for MON determination in cereal samples was developed.

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Turková, Jaroslava. "Affinity chromatography - Template chromatography of nucleic acids and proteins (Chromatographic Science Series, Vol. 27)". Journal of Chromatography B: Biomedical Sciences and Applications 377 (gennaio 1986): 475–76. http://dx.doi.org/10.1016/s0378-4347(00)80813-0.

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40

Hanai, Toshihiko. "Quantitative Explanation of Retention Mechanisms in Reversed-phase Mode Liquid Chromatography, and Utilization of Typical Reversed-phase Liquid Chromatography for Drug Discovery". Current Chromatography 6, n. 1 (18 settembre 2019): 52–64. http://dx.doi.org/10.2174/2213240606666190619120733.

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The retention mechanism in reversed-phase liquid chromatography was quantitatively described using log P (octanol-water partition coefficient). The hydrophobic (lipophilic) interaction liquid chromatography was then used to measure the hydrophobicity of a variety of compounds. Furthermore, the technique has been used as an analytical method to determine molecular properties during the drug discovery process. However, log P values cannot be applied to other chromatographic techniques. Therefore, the direct calculation of molecular interactions was proposed to describe the general retention mechanisms in chromatography. The retention mechanisms in reversed-phase liquid chromatography were quantitatively described in silico by using simple model compounds and phases. The competitive interactions between a bonded-phase and a solvent phase clearly demonstrated the retention mechanisms in reversed-phase liquid chromatography. Chromatographic behavior of acidic drugs on a pentyl-, an octyl-, and a hexenyl-phase was quantitatively described in the in silico analysis. Their retention was based on their hydrophobicity, and hydrogen bonding and electrostatic interaction were selectivity of the hexenyl-phase. This review focuses on the quantitative explanation of the retention mechanisms in reversed-phase liquid chromatography and the practical applications in drug discovery.

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Yatsenko, Larisa Anatolyevna, Maria Yurevna Printseva, Ilya Danilovich Cheshko e Artur Alexandrovich Tumanovsky. "Detection of residues and determination of the composition of combustible components in case of explosions of vapor-gas-air mixtures". Technology of technosphere safety 97 (2022): 51–60. http://dx.doi.org/10.25257/tts.2022.3.97.51-60.

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Introduction. Liquefied hydrocarbon gases (LHG) are widely used in various fields. The main components of LHG are: propane, isobutane and n-butane, which are not only combustible, but also explosive gases capable of detonation combustion. The detection of LHG in the air is a very urgent task in expert studies. To determine the component composition of various flammable liquids, for the purpose of their identification, chromatographs equipped with a capillary quartz column with a phase that allows detecting saturated hydrocarbons of the homologous series from pentane to pentatetracontane inclusive are used in the Forensic Expertise Institutions of Federal Fire Service of EMERCOM of Russia. However, it is not possible to analyze the component composition of lighter hydrocarbons according to the previously proposed and used in expert practice method for detecting and studying flammable liquids/high liquids under these conditions. To solve the problem of unification of the use of the instrumental base for the detection of residues of flammable liquids, liquid liquids and light hydrocarbons, new chromatography conditions were selected using the existing equipment set. Goals and objectives. The aim of the study is to select the analysis conditions for detecting the remains of liquefied hydrocarbon gases after explosions of steam-air mixtures on the basis of the instrumental gas chromatographic complex in service with the Forensic Expertise Institutions of Federal Fire Service of EMERCOM of Russia. Research methods. To detect and determine the composition of residues of combustible components during explosions of vapor-gas-air mixtures, a hardware-software instrumental complex based on a gas-liquid chromatograph equipped with a flame ionization detector, a ZB-50 capillary column, and an attachment from a two-stage thermal desorber was used. Results and its discussion. In the course of the study, the optimal conditions for conducting gas chromatographic analysis were defined and selected in order to detect liquefied hydrocarbon gases. Recommended pressures are given for various carrier gases. It is shown that, by varying the pressure and inlet temperature, light hydrocarbons propane, butane, isobutane is fairly well separated on a gas-liquid chromatograph with a flame ionization detector and on a ZB-50 capillary column 30 meters long. Conclusion. The research shows that the problem of combining a hardware-software instrumental complex based on a gas chromatograph with an attachment from a two-stage thermal desorber used for the analysis of two groups of substances (liquefied hydrocarbons and flammable liquids, gas liquids) is solved by varying the pressure and temperature of the input. Keywords: gas-liquid chromatography, thermal desorption, liquefied petroleum gases, light hydrocarbons, air-fuel mixtures, vapor-gas-air mixtures, explosion, fire examination.

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Edwards, Judson V., e Eivind B. Lillehoj. "Isolation and Liquid Chromatographic Determination of the Cyclic Peptide Mycotoxin Cyclosporin A from Rice". Journal of AOAC INTERNATIONAL 70, n. 1 (1 gennaio 1987): 126–29. http://dx.doi.org/10.1093/jaoac/70.1.126.

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Abstract A simple method for determination and quantitation of a cyclic peptide mycotoxin, cyclosporin A, in rice is presented. Rice inoculated with Trichoderma polysporum (Link ex Pers.) was extracted with methylene chloride after 4 weeks of incubation. Cyclosporin A was isolated from extracts by using open bed gel filtration column chromatography (LH-20, acetonitrile) and monitored with thin layer chromatography and reverse phase liquid chromatography coelution with a standard. Preliminary thin layer chromatographic methods were developed. Cyclosporin A was detected by iodine and after partial acid hydrolysis by ninhydrin and UV light. A liquid chromatographic method was developed that used a reverse phase disposable cartridge cleanup and isocratic chromatography with a reverse phase octadecylsilica column and a UV detector set at 212 nm. Recovery of cyclosporin A from spiked rice samples (mg/g range) was 85%.

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Cong, Jing Xiang, Shao Yan Wang e Hong Gao. "Separation of Liquiritin by Two-Dimensional Liquid Chromatography". Advanced Materials Research 455-456 (gennaio 2012): 1232–38. http://dx.doi.org/10.4028/www.scientific.net/amr.455-456.1232.

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Two-dimensional liquid chromatography (2DLC) is an important technology for the separation and analysis of complex samples. Liquiritin, an important active component in licorice, was chosen as the target compound and it was separated by three kinds of off-line 2DLC, i.e. size exclusion chromatography × reversed phase chromatography, normal phase × reversed phase chromatography and reversed phase chromatography × reversed phase chromatography (SEC×RP, NP×RP and RP×RP). The chromatographic conditions were selected and the 2D systems were combined. The results show that it is feasible to separate Liquiritin from licorice extract using 2DLC. Among the 2D modes mentioned above, the highest purity of Liquiritin was obtained in the RP×RP mode, and the concentration of Liquiritin was increased most significantly in the NP×RP mode.

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Yang, Yiwen, Yehui Wang, Zongbi Bao, Qiwei Yang, Zhiguo Zhang e Qilong Ren. "Progress in the Enantioseparation of β-Blockers by Chromatographic Methods". Molecules 26, n. 2 (17 gennaio 2021): 468. http://dx.doi.org/10.3390/molecules26020468.

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β-adrenergic antagonists (β-blockers) with at least one chiral center are an exceedingly important class of drugs used mostly to treat cardiovascular diseases. At least 70 β-blockers have been investigated in history. However, only a few β-blockers, e.g., timolol, are clinically marketed as an optically pure enantiomer. Therefore, the separation of racemates of β-blockers is essential both in the laboratory and industry. Many approaches have been explored to obtain the single enantiomeric β-blocker, including high performance liquid chromatography, supercritical fluid chromatography and simulated moving bed chromatography. In this article, a review is presented on different chromatographic methods applied for the enantioseparation of β-blockers, covering high performance liquid chromatography (HPLC), supercritical fluid chromatography (SFC) and simulated moving bed chromatography (SMB).

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Kosarev, E. L., e K. O. Muranov. "Chromatography+RECOVERY=superresolution chromatography". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 502, n. 2-3 (aprile 2003): 764–67. http://dx.doi.org/10.1016/s0168-9002(03)00576-x.

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Nishimura, Erica, Yin Nam Kwok e Christopher H. S. McIntosh. "Characterization of opioid peptides in the rat stomach". Biochemistry and Cell Biology 64, n. 8 (1 agosto 1986): 733–42. http://dx.doi.org/10.1139/o86-100.

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A combination of several chromatographic and assay systems was used to characterize the opioid peptides in rat stomach extracts. Partial purification of opioid material in acetic acid extracts of the corpus plus antrum regions of the rat stomach was carried out by gel filtration chromatography on Sephadex G-50, followed by adsorption onto Amberlite XAD-2 resin. A single peak in opioid activity was determined by both radioreceptor assay (RRA) and bioassay. By high performance liquid chromatography, this peak was resolved into five distinct components, characterized by RRA and (or) radioimmunoassay, with retention times corresponding to methionine enkephalin (met-enk), leucine enkephalin, met-enk-arg6-gly7-leu8, met-enk-arg6-phe7, and dynorphin 1–13. Closer examination of the dynorphin component revealed the presence of dynorphins 1–17, 1–13, and 1–8. Trypsin digestion of the partially purified (Sephadex G-50 and Amberlite XAD-2 chromatographed) extract resulted in an overall increase in opioid activity, suggesting the presence of larger, possibly precursor forms.

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Saad Rasheed, Ashraf, Bashaer A. Al-Phalahy e Mustafa J. Mohammed. "Modern Chromatographic Methods for Determination Flavonoids". Al-Nahrain Journal of Science 27, n. 2 (1 giugno 2024): 28–49. http://dx.doi.org/10.22401/anjs.27.2.00.

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Flavonoids are a prominent group of plant phenolics (polyphenol group)extensively present in the human diet and associated with health promotion. Flavonoids are essential in various pharmaceutical, nutraceutical, and cosmetic applications. To collect and categorize these compounds, we comprehensively assessedHigh-performance liquid chromatography (HPLC) techniques published to analyze flavonoids in various matrices. Mostdocumented methods employed liquid chromatography with ultraviolet detection (HPLC-UV) and tandem mass spectrometry (LC-MS/MS) methods. Among chromatographic techniques, reversed-phaseliquidchromatographyremains the predominant and efficient method for separating various analytes. This review explores the primary chromatographic methods used to separate and quantify flavonoids in herbs, fruits, and biological samples. This article exam inesrecent literature on applying liquid chromatography with different detection methods for analyzing flavonoids. To examine recent literature on applying liquid chromatography with different detection methods for analyzing flavonoids. It offers valuable insights to researchers as they prepare to develop quantification methods.

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Mekapothula, Subbareddy, A. D. Dinga Wonanke, Matthew A. Addicoat, David J. Boocock, John D. Wallis e Gareth W. V. Cave. "Supramolecular Chromatographic Separation of C60 and C70 Fullerenes: Flash Column Chromatography vs. High Pressure Liquid Chromatography". International Journal of Molecular Sciences 22, n. 11 (27 maggio 2021): 5726. http://dx.doi.org/10.3390/ijms22115726.

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A silica-bound C-butylpyrogallol[4]arene chromatographic stationary phase was prepared and characterised by thermogravimetric analysis, scanning electron microscopy, NMR and mass spectrometry. The chromatographic performance was investigated by using C60 and C70 fullerenes in reverse phase mode via flash column and high-pressure liquid chromatography (HPLC). The resulting new stationary phase was observed to demonstrate size-selective molecular recognition as postulated from our in-silico studies. The silica-bound C-butylpyrogallol[4]arene flash and HPLC stationary phases were able to separate a C60- and C70-fullerene mixture more effectively than an RP-C18 stationary phase. The presence of toluene in the mobile phase plays a significant role in achieving symmetrical peaks in flash column chromatography.

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Diroh, Vina Awallina, Rio Gusraya Unaldi, Mutiara Wayu Puspasari e Muhammad Muzhil Aslam. "NSAID Analysis Using Chromatographic and Spectrophotometric Methods". Asian Journal of Analytical Chemistry 1, n. 1 (7 giugno 2023): 12–17. http://dx.doi.org/10.53866/ajac.v1i1.269.

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The purpose of this review article to evaluate the content of Nonsteroidal anti-inflammatory drugs (NSAID) using chromatographic and spectrophotometric methods. This journal review uses seven analytical methods on NSAID , namely high performance liquid chromatography (HPLC), fourier transform infrared (FTIR), gas chromatography (GC), thin layer chromatography (TLC), and spectrophotometry methods. The outcomes of every method have been elaborated in this paper and all of them can be used to detect the NSAID compounds.

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Brämer, Chantal, Lisa Tünnermann, Alina Gonzalez Salcedo, Oscar-Werner Reif, Dörte Solle, Thomas Scheper e Sascha Beutel. "Membrane Adsorber for the Fast Purification of a Monoclonal Antibody Using Protein A Chromatography". Membranes 9, n. 12 (27 novembre 2019): 159. http://dx.doi.org/10.3390/membranes9120159.

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Abstract (sommario):

Monoclonal antibodies are conquering the biopharmaceutical market because they can be used to treat a variety of diseases. Therefore, it is very important to establish robust and optimized processes for their production. In this article, the first step of chromatography (Protein A chromatography) in monoclonal antibody purification was optimized with a focus on the critical elution step. Therefore, different buffers (citrate, glycine, acetate) were tested for chromatographic performance and product quality. Membrane chromatography was evaluated because it promises high throughputs and short cycle times. The membrane adsorber Sartobind® Protein A 2 mL was used to accelerate the purification procedure and was further used to perform a continuous chromatographic run with a four-membrane adsorber-periodic counter-current chromatography (4MA-PCCC) system. It was found that citrate buffer at pH 3.5 and 0.15 M NaCl enabled the highest recovery of >95% and lowest total aggregate content of 0.26%. In the continuous process, the capacity utilization of the membrane adsorber was increased by 20%.

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