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Journal of Chromatographic Science

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
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
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
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
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
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
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
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
Tayse Ferreira Ferreira da Silveira, Helena Teixeira Godoy
Currently available high-performance liquid chromatographic (HPLC) methods for the analysis of non-anthocyanin compounds in açaí are time-consuming or employ complex and costly detection systems. Therefore, we hypothesized that by using ultrahigh-performance liquid chromatography interfaced with a diode array detector (UHPLC-DAD) in conjunction with multivariate optimization tools (response surface methodology, Derringer and Suich desirability) would give a simple, fast, effective and reliable method to determine eight phenolic acids and four flavonoids in açaí juice...
October 26, 2018: Journal of Chromatographic Science
Jialin Du, Can Gong, Xingli Pei, Haiyan Zhao, Xu Xu
Castor oil is a traditional Chinese medicine containing a chemically complex mixture of triacylglycerols (TAGs). Herein, the TAGs in castor oil were analyzed in detail. First, the fatty acid composition of castor oil was examined via methylated derivatisation followed by gas chromatography-mass spectrometry (GC-MS). Then, using the fatty acid composition data, liquid chromatography-mass spectrometry (LC-MS) was applied to analyze the composition and relative content of TAGs. Nine TAGs were identified, wherein triricinolein (RRR) constituted ~81% of the total TAG content based on the peak areas...
October 6, 2018: Journal of Chromatographic Science
S Raghavender Reddy, K Hussain Reddy, M Narendra Kumar, P Madhava Reddy, J Venkata Ramana Reddy, Hemant Kumar Sharma
A specific GC-MS method has been developed, optimized and validated for the determination of five genotoxic impurities namely Methyl bromide (Me.-Br), Ethyl bromide (Et.-Br), Isopropyl bromide (Ipr.-Br), n-Propyl bromide (n-Pr.-Br) and n-Butyl bromide (n-But.-Br) in Divalproex sodium (DPS) drug substance. Chromatographic separation of five genotoxic impurities was achieved on DB-1 column (30 m × 0.32 mm, 3.0 μm), consists of 100% dimethyl polysiloxane as stationary phase and passing helium carrier gas. The mass fragments (m/z) were selected for the quantification of Me...
October 4, 2018: Journal of Chromatographic Science
Samy Emara, Walaa Zarad, Maha Kamal, Ahmed Ali, Yasmine Aboulella
Rapid and simple micellar electrokinetic chromatography (MEKC) with in-capillary derivatization and fluorescence detection has been developed to determine morphine in human serum. The sample was introduced into a background electrolyte (BGE) containing potassium ferricyanide, whereas morphine was oxidized into highly fluorescent product, pseudomorphine. Different parameters for derivatization and subsequent separation were systematically investigated for the analysis of morphine in serum. Efficient performance of the developed MEKC system was carried out in a single run using BGE made up of 70 mM sodium tetraborate decahydrate (pH 10...
October 1, 2018: Journal of Chromatographic Science
Nada S Abdelwahab, Nouruddin W Ali, Marco M Zaki, Souty M Z Sharkawi, Mohamed M Abdelkawy
Two validated chromatographic methods have been developed for the simultaneous determination of thalidomide (THD) and dexamethasone (DEX) in rat plasma using paracetamol (PAR) as an internal standard (IS). Chromatographic analysis was achieved firstly by HPLC method on C18 column (150 × 4.6 mm2 i.d., 5 μm) and a mobile phase composed of ethanol:water (containing 0.1% acetic acid) (70:30, v/v) at the flow rate of 0.6 mL min-1. The second method was HPTLC method which depended on using a developing system of methylene chloride:acetone:ethyl acetate (7:4:1, by volume)...
October 1, 2018: Journal of Chromatographic Science
Hongjiang Chen, Tao Ji, Jianwei Chen, Xiang Li
A simple and rapid method, based on matrix solid-phase dispersion (MSPD) and high-performance liquid chromatography (HPLC) was developed for simultaneous determination of nine lignans, including (-)-(7R,8R)-machilin D (Wang, C., Wang, P., Chen, X., Wang, W., Jin, Y.; Saururus chinensis (Lour.) Baill blocks enterovirus 71 infection by hijacking MEK1-ERK signaling pathway; Antiviral Research, (2015); 119:47-56), dihydroguaiaretic acid (Quan, Z., Lee, Y.J., Yang, J.H., Lu,Y., Li,Y., Lee,Y.K., et al.; Ethanol extracts of Saururus chinensis suppress ovalbumin-sensitization airway inflammation; Journal of Ethnopharmacology, (2010); 132:143-149...
October 1, 2018: Journal of Chromatographic Science
Xiaoxun Han, Yiming Xie, Qin Wu, Shuaibin Wu
In this work, two kinds of monolith-based immobilized enzyme microreactors (IMER) were compared in terms of monolith properties and digestion performance. Two monoliths were prepared involving poly (tetraethoxysiLane-co-3-aminopropyltriethoxysilane) (poly (TEOS-co-APTES)) monolith and poly (N-acryloxysuccinimide-co-acrylamide-co-ethylene dimethacrylate) (poly (NAS-co-AA-co-EDMA)) monolith for covalent trypsin immobilization. A higher chromatographic permeability constant 66.7 was obtained from the poly (TEOS-co-APTES) monolith in comparison with only 4...
October 1, 2018: Journal of Chromatographic Science
Yi Tao, Surun Huang, Weidong Li, Baochang Cai
Radix Dipsaci is employed for treating bone fractures in traditional Chinese medicine. In the current, a quantitative approach was established for determination of ten bioactive components (loganic acid, loganin, 3,5-diCQA, 4-CQA, 3,4-diCQA, sweroside, dipsacussaponin B, dipsacoside A, asperosaponin V and asperosaponin VI) in raw and rice wine-sautéed Radix Dipsaci by using UPLC-Q-TOF-MS based approach. The sample handling procedure was optimized. Chromatographic separation was operated on a Thermo Syncronis AQ-C18 UPLC column with mobile phase consisting of 0...
September 21, 2018: Journal of Chromatographic Science
Shilpi Chopra, Lauren Ridley, Wyatt R Murphy, John R Sowa, Carolyn S Bentivegna, Nicholas H Snow
Headspace solid-phase microextraction (HS-SPME) was used in combination with gas chromatography-mass spectrometry (GC-MS) for the analysis of polycyclic aromatic hydrocarbons (PAH) at part per billion levels in fish oil samples collected from menhaden fish. The method was initially developed using fish oil from capsules spiked with a standard PAH mixture. The final HS-SPME-GC-MS method presented a linear range from 3 to 1,500 ng/g, with precision for most analytes <10% relative standard deviation. The limits of detection varied from 1 to 7 ng/g depending on the analyte...
September 12, 2018: Journal of Chromatographic Science
Ilona Kiszkiel-Taudul, Barbara Starczewska
A new extraction method was developed for isolation of the antihistaminic drugs (histamine H2 receptor antagonists) famotidine (FMT) and nizatidine (NZT) from aqueous samples. A low solvent consumption method using dispersive liquid-liquid microextraction (DLLME) was applied for this purpose. The parameters of the isolation, namely, volume of extraction and disperser solvents, pH of sample and shaking time were optimized. The influence of foreign substances on the extraction process was also studied. After separation of FMT and NZT using DLLME, the analytes in organic extracts were determinated by high-performance liquid chromatography combined with UV spectrophotometry and liquid chromatography connected with tandem mass spectrometry (LC-MS-MS)...
August 31, 2018: Journal of Chromatographic Science
Anurak Choemang, Kesara Na-Bangchang
A simple, sensitive, selective and reproducible method based on liquid chromatography was developed for the determination of piperaquine in human plasma samples. Sample preparation involved a single step liquid-liquid extraction by organic solvents (hexane: tert-butyl methylether at the ratio of 1:1, v:v). Piperaquine was separated from the internal standard mefloquine on a reversed-phase C18 column, with the mobile phase consisting of a mixture of acetonitrile and 0.1% trichloroacetic acid (in water) (15:85, v:v) running at a flow rate of 1...
August 31, 2018: Journal of Chromatographic Science
Farah Safdel, Fariba Safa
In this work, a combination of Xu and atom-type-based AI topological indices (TIs) were employed for quantitative structure-retention relationship (QSRR) study of monomethylalkanes (MMAs). A total of 196 temperature-programmed gas chromatographic retention indices corresponding to all C4-C30 MMAs on OV-1 stationary phase have been used in QSRR modeling. Results of the study showed that an artificial neural network (ANN) with 4-9-1 topology and Levenberg-Marquardt training algorithm can predict the retention indices with high degree of accuracy...
August 28, 2018: Journal of Chromatographic Science
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