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Journal of Chromatographic Science

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https://www.readbyqxmd.com/read/30615111/comparative-study-of-quinolines-and-tetrahydroquinolines-sorption-on-various-sorbents-from-water-acetonitrile-solutions
#1
Nadezhda A Nekrasova, Svetlana V Kurbatova
The retention of 16 quinoline and tetrahydroquinoline derivatives was investigated under liquid chromatography conditions using porous graphitized carbon (PGC), octadecyl silica (ODS) and hypercrosslinked polystyrene (HCLP) stationary phases. For most of the analytes, retention on PGC was greater than on ODS, while retention on HCLP was even greater than on both ODS and PGC. The non-linearity of retention dependencies on acetonitrile content in the eluent was observed for compounds containing carboxy, hydrazo and methoxy groups...
January 7, 2019: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30615100/validated-chromatographic-methods-for-simultaneous-determination-of-calcipotriol-monohydrate-and-betamethasone-dipropionate-in-the-presence-of-two-dosage-form-additives
#2
Hanan A Merey, Sally S El-Mosallamy, Nagiba Y Hassan, Badr A El-Zeany
Two chromatographic methods were developed, optimized and validated for simultaneous determination of calcipotriol monohydrate (CPM) and betamethasone dipropionate (BMD) in the presence of two dosage form additives named; butylated hydroxytoluene (BHT) and alpha-tocopherol (TOCO). The proposed methods were accurate, sensitive and specific. The first method based on using aluminum thin-layer chromatographic plates precoated with silica gel GF254 as a stationary phase and chloroform-ethyl acetate-toluene (5:5:3, by volume) as a developing system...
January 7, 2019: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30615090/with-or-without-internal-standard-in-hplc-bioanalysis-a-case-study
#3
Silvia Imre, Amelia Tero-Vescan, Maria Titica Dogaru, László Kelemen, Daniela-Lucia Muntean, Augustin Curticapean, Noémi Szegedi, Camil-Eugen Vari
The mandatory strategy of using internal standard in HPLC is still controversial. Despite that the introduction of internal standard methodology in the early stage of development of HPLC technology was used to improve method accuracy and precision, there are still practical situations in which a simple external standard quantification is adequate. The aim of the study is to compare the determination of meloxicam (MXC) in human plasma by HPLC with or without using an internal standard according to some key points related to the reason of introducing the internal standardization such as the reducing of sample preparation errors or variability for low injection volumes...
January 7, 2019: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30608572/high-performance-thin-layer-chromatography-method-for-simultaneous-determination-of-antipsychotic-and-medicinally-important-five-%C3%AE-carboline-alkaloids
#4
Nitin Suryakant Kadam, Archana Ashokrao Naik, Pooja Jignesh Doshi, Tukaram Dayaram Nikam
This is the first report on the development and validation of high-performance thin-layer chromatography (HPTLC) method for simultaneous analysis of five antipsychotic and medicinally important β-carboline alkaloids (βCAs), namely, harmalol, harmaline, harmine, harmane and norharmane. These βCAs occurs in both plant and animal system including human being. In the present investigation, their best separation was achieved using an optimized mobile phase, chloroform: methanol: glacial acetic acid (7.8:2.2:0...
January 4, 2019: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30590524/fingerprint-analysis-and-multi-component-determination-of-ribonucleic-acid-for-injection-ii-recipe-by-hplc-dad-and-lc-esi-ms-methods
#5
Wei Zheng, Duoduo Xu, Mingxing Wang, Yanqiu Zhang, Qipin Gao, Yang Gao
Using high-performance liquid chromatography (HPLC), a quantitative method was developed to control the quality of ribonucleic acid for injection II (RA-II), which is used as an anti-cancer drug clinically in China. Using nuclease enzyme and under optimal hydrolysis conditions, the unstable RNA was hydrolyzed into stable nucleosides and nucleotides, which were easily detected by HPLC with diode array detection. Furthermore, by analyzing HPLC chromatograms of 10 batches of samples, six common peaks, namely, cytosine nucleotide, uracil nucleotide, adenine nucleotide, guanine nucleotide, guanosine and adenine, were identified by a HLPC coupled with electrospray ionization mass spectrometry...
December 22, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30566585/preparative-separation-of-quercetin-ombuin-and-kaempferide-from-gynostemma-pentaphyllum-by-high-speed-countercurrent-chromatography
#6
Conglei Pan, Haitao Lü
An efficient method for the preparative separation of quercetin, ombuin and kaempferide from Gynostemma pentaphyllum by high-speed countercurrent chromatography (HSCCC) was successfully developed for the first time. The extraction conditions were optimized by an orthogonal array design L9 (34), while quercetin, ombuin and kaempferide were efficiently released from rutin, ombuoside and kaempferide glucoside by hydrochloric acid hydrolysis, respectively. Quercetin was purified by HSCCC with two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) in a single run...
December 19, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30566583/optimized-liquid-chromatography-tandem-mass-spectrometry-for-otaplimastat-quantification-in-rat-plasma-and-brain-tissue
#7
Seolhee Lee, Miri Kim, Ju-Hee Oh, Joo Hyun Lee, Naree Shin, Taehoon Park, Ji Hyeon Lee, Min Chang Kim, Young-Joo Lee
An optimized liquid chromatography-tandem mass spectrometry method for simple and sensitive quantification of Otaplimastat in rat plasma and brain tissue was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation method based on recovery and matrix effect. The chromatographic separation of the sample was performed on a reverse-phase AQ column with an isocratic mobile phase consisting of 10 mM ammonium acetate (pH 4.0) and acetonitrile (50:50, v/v). The analyte was quantified by multiple reaction monitoring with a Waters Quattro micro™ API mass spectrometer...
December 19, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30566573/development-and-validation-of-stability-indicating-uplc-pda-ms-for-the-determination-of-imiquimod-and-its-eight-related-substances-application-to-topical-cream
#8
Venu Balireddi, Siva Rao Tirukkovalluri, Krishna Murthy Tatikonda, Bhanu Teja Surikutchi, Parmita Mitra
A stability indicating analytical method for imiquimod and its related impurities was developed by ultra-pressure liquid chromatography (UPLC) using design of experiments. This method could quantify imiquimod and all its eight known related impurities in a single run. The optimum separation was achieved on reverse phase Acquity UPLC column (2.1 mm × 100 mm, 1.7 μm) using 0.1% trifluoroacetic acid and acetonitrile as mobile phase. Preventing the use of ion pair reagents assured the compatibility of this method to liquid chromatography in tandem with mass spectrometry...
December 19, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30566568/response-surface-methodology-of-pre-concentration-of-chorophenols-from-seawater-samples-by-molecularly-imprinted-stir-bar-sorptive-extraction-combined-with-hplc-box-behnken-design
#9
S H Hashemi, F Najari
A novel molecularly imprinted polymer coated stir bar was prepared using 2-chlorophenol (2-CP) as template molecule and used for selective extraction of phenolic compounds including chlorophenols (CPs) directly from seawater samples. Various parameters affecting extraction have been evaluated using one variable-at-a-time and Box-Behnken design. A three-level Box-Behnken experimental design by six factors, which combined the response surface methodology, was used to optimize the selective extraction of the CPs...
December 19, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30535186/modeling-retention-behavior-on-analysis-of-hallucinogenic-mushrooms-using-hydrophilic-interaction-liquid-chromatography
#10
Norbert Rácz, Júlia Nagy, Wen Jiang, Tibor Veress
The goal of this work was to investigate and compare the selectivity of three different hydrophilic interaction liquid chromatography (HILIC) charge modulated amide columns, iHILIC®-Fusion, iHILIC®-Fusion(+) and iHILIC®-Fusion(P), for analysis of compounds in hallucinogen mushrooms. An extract of a truffle-like fungus containing psilocin, psilocybin and baeocystin was chosen as test material. Three different modeling methods were applied to describe the retention times of constituents in isocratic separation mode as a function of mobile phase composition, pH and temperature...
December 7, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30496359/a-high-throughput-three-step-ultra-performance-liquid-chromatography-tandem-mass-spectrometry-method-to-study-metabolites-of-atractylenolide-iii
#11
Zhihui Jiang, Chunyan Peng, Wenping Huang, Bei Wu, Dan Zhang, Hui Ouyang, Yulin Feng, Shilin Yang
Atractylodes macrocephala Koidz (AMK) is a traditional Chinese medicine widely used in the treatment of various diseases, especially spleen deficiency. As the principle active constituents of AMK, however, the metabolites of Atractylenolide-III (A-lactone-III) have not been identified in rats yet. In this study, a three-step high throughput method based on UHPLC-Q-TOF-MS-MS was developed to profile and characterize the metabolites of A-lactone-III in rat feces, urine and plasma. The initial step was a full-scan that utilized a multiple mass defect filter (MMDF) combined with dynamic background subtraction (DBS)...
November 29, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30496348/simultaneous-quantification-of-benznidazole-and-posaconazole-by-hplc-dad-using-qbd-approach
#12
Ana Cristina Sousa Gramoza Vilarinho Santana, Lucas José de Alencar Danda, Livio Cesar Cunha Nunes, Jose Lamartine Soares Sobrinho
Objective: To develop an analytical method to simultaneous quantification of benznidazole (BNZ) and posaconazole (POS) by high-performance liquid chromatography with diode-array detection (HPLC-DAD) using design of experiments. Methods: Percentages of organic phase, buffer pH and flow rates of mobile phase were selected as independent variables by full factorial design (33), totaling 27 experiments. Significant factors were evaluated using factorial analysis of variance with 95% confidence level...
November 29, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30395213/development-and-validation-of-lc-ms-ms-assay-for-the-determination-of-the-emerging-alkylating-agent-laromustine-and-its-active-metabolite-in-human-plasma
#13
Ala F Nassar, Adam V Wisnewski, Terence Wu, Tukiet T Lam, Ivan King
The objective of this study was to validate a method for the determination of laromustine (VNP40101M) and short-lived its active metabolite (VNP4090CE) that has a half-life in human blood of <90 s in human plasma by liquid chromatography (LC) with tandem mass spectrometric (MS/MS) detection. We overcome the stability dilemma by acidified the human plasma with citric acid. Laromustine "breaks" down on the source of mass spectrometry to give m/z 249 which is the same m/z for VNP4090CE. Because VNP4090CE and laromustine elute at approximate retention time of 1...
November 3, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30395212/hptlc-method-for-simultaneous-determination-of-norfloxacin-and-tinidazole-in-presence-of-tinidazole-impurity
#14
Ibrahim A Naguib, Eglal A Abdelaleem, Eman S Hassan, Nouruddin W Ali
Sensitive, selective and accurate high-performance thin layer chromatographic HPTLC method for quantitative determination of Norfloxacin (NF), Tinidazole (TZ) and 2-Methyl-5-nitroimidazole (MNZ) as potential impurity of Tinidazole is developed and validated in the presented work. Calibration curves were linear over the concentration ranges of 0.4-2.4, 0.4-1.6, 0.2-1.2 μg/band for NF, TZ and MNZ, respectively. The method depends on separation and quantitation of NF, TZ and MNZ on aluminium plates pre-coated with silica gel HPTLC 60F254 as stationary-phase using chloroform: methanol: formic acid (7...
November 3, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30395207/separation-and-characterization-of-unknown-impurities-and-isomers-in-cefminox-sodium-and-study-of-the-forming-mechanisms-of-impurities-by-liquid-chromatography-coupled-with-ion-trap-time-of-flight-mass-spectrometry
#15
Yu Xu, Dandan Wang, Lan Tang, Jian Wang
Thirteen unknown impurities and isomers in cefminox sodium were separated and characterized by liquid chromatography coupled with high-resolution ion trap/time-of-flight mass spectrometry (LC-IT-TOF-MS) with the positive mode of electrospray ionization (ESI) method. New HPLC-gradient elution method was developed for the detection of impurities in cefminox sodium. And the ESI ion trap multiple-stage tandem mass spectrometry had been applied successfully to the direct investigation of impurities and isomers in cefminox sodium...
November 3, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30395199/stability-indicating-rp-uplc-method-for-simultaneous-determination-of-azilsartan-medoxomil-and-chlorthalidone-in-tablets-in-the-presence-of-its-degradation-products
#16
Lobna A Hussein, Nancy N Magdy, Michael A Ibrahim
Azilsartan Medoxomil (AZL) angiotensin II receptor blocker and chlorthalidone (CLT) were determined by ultraperformance liquid chromatography (UPLC) method in their combined dosage form, they were both subjected to forced degradation studies under extensive stress conditions. The method is a stability indicating by resolving the investigated drugs from their degradation products. Moreover, the degradation products for both drugs obtained from forced degradation were subjected to LC-MS for structure elucidation...
November 3, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30395170/application-of-dopant-assisted-atmospheric-pressure-photoionisation-hplc-ms-method-for-the-sensitive-determination-of-polycyclic-aromatic-hydrocarbons-in-dark-chocolate
#17
Irina Rozentale, Dzintars Zacs, Vadims Bartkevics
Multiple food research studies have shown that the polycyclic aromatic hydrocarbon (PAHs) are frequently found in processed cocoa products and chocolate. In a present study a method based on dopant-assisted atmospheric pressure photoionisation (DA-APPI) combined with a liquid chromatography/high-resolution mass spectrometer (HPLC-HRMS) for high-sensitivity analysis of four EU marker PAHs in dark chocolate samples was developed and fully validated according to the performance criteria set in EU guidelines. PAHs detection was achieved by HRMS in positive electrospray ionization mode with toluene used as a dopant to enhance the ionization efficiency of non-polar PAHs...
November 3, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30371764/a-high-performance-liquid-chromatography-method-for-determination-of-genotoxic-impurity-hydroxylamine-in-drug-substances
#18
Thangarathinam Kumar, N Xavier, Mohandass Ramya
Hydroxylamine (NH2OH) is widely used in pharmaceutical intermediates and final drug substances synthesis. Since hydroxylamine is a well-known genotoxic impurity compound that needs to be controlled down to ppm level in pharmaceutical compounds. It is very difficult to detect using conventional analytical techniques due to its physical-chemical properties like the lack of chromophore, low molecular weight, the absence of carbon atom and high polarity. In addition to that, the analysis of the pharmaceutical samples encounters considerable obstruction from matrix components that greatly overshadow the response of hydroxylamine...
October 29, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30364978/hptlc-densitometric-method-for-determination-of-ascorbic-acid-paracetamol-and-guaifenesin-in-presence-of-their-toxic-impurities
#19
Nada S Abdelwahab, Eglal A Abdelaleem, Maha M Abdelrahman
Ascorbic acid (ASC), paracetamol (PAR) and guaifenesin (GUF) are co-formulated together as analgesic and expectorant effervescent powder. This work describes a selective stability indicating HPTLC-densitometric method which is the first developed stability indicating one for chromatographic separation of the three studied drugs in presence of paracetamol toxic impurity [4-aminophenol (4-AP)] and guaifenesin related substance [impurity, (guaiacol) (GUC)]. The chromatographic separation was carried out on HPTLC 60F254 plates using chloroform-acetone-trifluoroacetic acid (6...
October 26, 2018: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/30364970/green-tailoring-with-water-of-choline-chloride-deep-eutectic-solvents-for-the-extraction-of-polyphenols-from-palm-samples
#20
Xiao Liu, Najing Fu, Qiangguo Zhang, Shuaifang Cai, Qiong Wang, Dandan Han, Baokun Tang
To address the problem of high viscosity of deep eutectic solvents (DESs), the viscosities of a series of choline chloride-based DESs and DESs-H2O were determined, and their extraction efficiencies were obtained for the extraction of polyphenols in palm samples. Tailoring the DESs by the addition of water successfully adjusted their viscosity from thousand to single-digit mPa s and aided the extraction of polyphenols from samples, by changing the hydrogen-bonding interactions of DESs. Among the compounds investigated, choline chloride-oxalic acid-water of DESs-H2O with various molar ratios with 1:0...
October 26, 2018: Journal of Chromatographic Science
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