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Isocorynoxeine is one of the main alkaloids in Chinese medicinal herbs, and has pharmacological activities such as antihypertensive, sedative, anticonvulsant, and neuronal protection. It is an effective component of Uncaria for the treatment of hypertension. In this study, we used a fast and sensitive ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) to detect isocorynoxeine in rat plasma and investigated its pharmacokinetics in rats. Six rats were given isocorynoxeine (15 mg/kg) by intraperitoneal (i.p.) administration. Blood (100 μL) was withdrawn from the caudal vein at 5 and 30 min and 1, 2, 4, 6, 8, 12, and 24 h after administration. Chromatographic separation was achieved using a UPLC BEH C18 column using a mobile phase of acetonitrile–0.1% formic acid with gradient elution. Electrospray ionization (ESI) tandem mass spectrometry in the multiple reaction monitoring (MRM) mode with positive ionization was applied. Intra-day and inter-day precisions (relative standard deviation, %RSD) of isocorynoxeine in rat plasma were lower than 12%. The method was successfully applied in the pharmacokinetics of isocorynoxeine in rats after intraperitoneal administration. The t 1/2 of isocorynoxeine is 4.9 ± 2.1 h, which indicates quick elimination.

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Berendsen, B.J.A., Essers, M.L., Stolker, A.A.M. & Nielen, M.W.F. (2011): Quantitative trace analysis of eight chloramphenicol isomers in urine by chiral liquid chromatography coupled to tandem mass spectrometry. J. Chromatogr. A ., 1218 , 7331

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Summary

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of glycyrrhizin, formononetin, glycyrrhetinic acid, liquiritin, isoliquiritigenin, and licochalcone A in licorice. An Eclipse Plus C18 column (I.D. 4.6 × 100 mm, 3.5 μm particle size; Agilent) was used in the analysis. Electrospray ionization (ESI)-tandem interface in the negative mode was performed, and multiple reaction monitoring (MRM) was employed with the precursor multiple reaction monitoring production combination for the determination of six analytes. The average recoveries ranged from 98.30% to 100.13% with relative standard deviations (RSDs) ≤ 1.95%, and limits of detection (LODs) ranged from 2.1 to 3.6 pg. The applicability of this analytical approach was confirmed by the successful analysis of six samples. The results indicated that the established method was validated, sensitive, and reliable for the determination of six analytes in licorice.

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Acta Chromatographica
Authors: Gobinda Chandra Acharya, Naresh Ponnam, Meenu Kumari, Tapas Kumar Roy, Kodthalu Seetharamaiah Shivashankara, and Manas Ranjan Sahoo

Abstract

Spiny coriander (Eryngium foetidum L.) is a perennial medicinal herb grown in the tropical regions worldwide. In India, it is used as a potential spice for garnishing and flavoring the dishes and treating several ailments. Eryngium spp. found in coastal Odisha, India has a strong aroma similar to the seasonal Coriandrum. The volatile flavor constituents of the unique plants were analyzed through headspace solid-phase microextraction (HS-SPME) using capillary gas chromatography (GC) and gas chromatography-tandem mass spectrometry (GC–MS/MS). The volatile compounds exhibited high chemodiversity, with 10-undecenal as the major component in leaves (44.98%) and branches (57.43%). Fourier-transform infrared (FTIR) spectroscopy identified eight major peaks grouped into six main regions. Chemo profiles of these two corianders were overlapped and showed similar area differences in the spectral peak. The lesser-known perennial Eryngium with high chemodiversity would be a better alternative to the seasonal coriander for aromatic, pharmaceutical, and industrial uses.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Emil Mincsovics, Péter Ott, Ágnes Alberti, Andrea Böszörményi, Éva Héthelyi, Éva Szőke, Ágnes Kéry, Éva Lemberkovics, and Ágnes Móricz

Bioassay-guided isolation of antibacterial components of chamomile flower methanol extract was performed by overpressured layer chromatography (OPLC) with on-line detection, fractionation combined with sample clean-up in-situ in the adsorbent bed after off-line sample application. The antibacterial effect of the eluted fractions and of those compounds remaining on the adsorbent layer after separation was tested with direct bioautography (DB) against the bioluminescent Pseudomonas savastanoi pv. maculicola and Vibrio fischeri. The fractions with high biological activity were analyzed by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and liquid chromatography and tandem mass spectrometry (LC-MS/MS). Two active uneluted compounds were characterized by off-line OPLC-MS using a thin-layer chromatography (TLC)-MS interface. Mainly, essential oil components, coumarins, flavonoids, phenolic acids, and fatty acids were identified in the active fractions.

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A simple, selective, and sensitive thin-layer chromatographic—densitometric method has been developed for the determination of sulfasalazine besides its possible impurities in pharmaceutical preparations. The mobile phase was composed of ethyl acetate—methanol—ammonia 25% 10:7:3 (υ/υ/υ), and the stationary phase was aluminum plates precoated with silica gel 60 F254 that enabled to obtain well resolved peaks of sulfasalazine and its impurities. The developed chromatograms were analyzed densitometrically at λ = 360 nm. R F values and ultraviolet (UV) spectra were used to identify the compounds. The developed method is highly sensitive (limit of detection [LOD] = 17.11 ng spot−1, limit of quantitation [LOQ] = 51.84 ng spot−1), precise (relative standard deviation [RSD] = 1.43%–4.28%), and accurate (RSD = 1.64%–4.27%). The linearity of the method was checked within the range 20–120 ng spot−1. The method was successfully applied for the determination of sulfasalazine in pharmaceutical preparations besides its impurities. The structures of impurities present in the standard substance and in pharmaceutical preparations were established by ultra-performance liquid chromatography—tandem mass spectrometry (UPLC—MS/MS) technique.

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A comparative proteomic analysis of grain proteins during five grain developmental stages of wheat cultivar Chinese Spring (CS) and its 1Sl/1B substitution line CS-1Sl(1B) was carried out in the current study. A total of 78 differentially expressed protein (DEP) spots with at least 2-fold expression difference were detected by two-dimensional electrophoresis (2-DE). Among these, 73 protein spots representing 55 differentially expressed proteins (DEPs) were successfully identified by matrix-assisted laser desorption/ionization time-offlight tandem mass spectrometry (MALDI-TOF/TOF-MS). Differential protein spots between the two genotypes were analyzed by cluster software, which revealed significant proteome differences. There were 39 common spots (including 33 DEPs) that showed significant difference between the two lines across five grain developmental stages, of which 14 DEP spots (including 11 DEPs) were mainly involved in carbohydrate metabolism that were encoded by the genes on 1B chromosome while 25 DEP spots (including 12 DEPs) were mainly related to stress response and gluten quality that were encoded by 1S1 chromosome. These results indicated that the Sl genome harbors more stress and quality related genes that are potential valuable for improving wheat stress resistance and product quality.

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High-performance liquid chromatography coupled with fluorescence (HPLC-FD) and tandem mass spectrometric detection (LC-MS/MS) was studied as a versatile tool for fast and reliable determination of nine regulated quinolones in food of animal origin (Council Regulation 2377/90/ECC). The sample pre-treatment protocol includes double step extraction with acetonitrile followed by solid phase extraction (SPE) cleanup on hydrophobic-lipophilic balance (HLB) cartridge. The separation of quinolones in HPLC-FD determination was performed on C18 Zorbax column with a gradient mixture of aqueous formic acid, methanol, and acetonitrile. A multi-wavelength excitation/emission program was used for sensitive quinolones detection. The separation efficiency of newly available chromatographic columns: Gemini C18 and Synergi Polar RP (fully porous particles), as well as Kinetex PFP and Poroshell 120 EC-C18 (core-shell particles), was studied in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. Appropriate gradient elution program was designed for each column. Multiple reaction monitoring was used for selective determination of each quinolone. LC-MS/MS allowed quinolones determination in less than 5 min. Both methods showed detection limits below maximum residue limits for quinolones residues in food commodities.

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Eupatilin, mainly derived from Artemisia asiatica (Asteraceae), is an O-methylated flavone with various bioactivities. In the present study, a validated ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established for the quantification of eupatilin in rat plasma with the internal standard (IS) of tussilagone and the protein precipitation of plasma samples was performed using acetonitrile–methanol (9:1, v/v). The eupatilin and IS were eluted separately on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with the gradient mobile phase consisted of 0.1% formic acid and acetonitrile. The protonated analytes were quantified by multiple reactions monitoring (MRM) mode with an electrospray ionization (ESI) source operated in positive ion mode. The calibration plots were found to be linear over the range from 2 to 1000 ng/mL for eupatilin in rat plasma. Both of the intra-day and inter-day precision variations (RSDs) were ≤13%. The recoveries of eupatilin in rat plasma were between 83.7% and 94.6%, and the accuracy of the method ranged from 95.8% to 107.6%. In addition, the validated method was applied to pharmacokinetic study of eupatilin after an intravenous dose of 2 mg/kg to rats.

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Abstract

Chronic hepatitis B virus (HBV) carriers may develop hepatocellular carcinoma (HCC) by a wide range of mechanisms including angiogenesis. We show that HBV replication induces the expression of angiogenic proteins interleukin 6 (IL6) and cyclooxygenase-2 (Cox2). Interestingly, ibuprofen (a Cox2 inhibitor) is found to attenuate the levels of IL6 and Cox 2 which are induced by HBV replication.

The mechanism of attenuation of angiogenic proteins by ibuprofen was further investigated. Our results show that HBx is involved in the increase of the expression of Cox2 through the NFκB pathway. However, the expression of Cox2 is decreased when the HBx-expressing cells are incubated with ibuprofen. The contrasting effect of HBx on Cox2 is found to be determined by differential dimer formation among the members of the NFκB family of proteins, including NFκB, RelA, and C-rel. Specifically, HBx alone results in dimer formation between NFκB and RelA, while the combined presence of HBx and ibuprofen leads to the formation of NFκB and C-rel. Additional information on the interaction network involving HBx, ibuprofen, and NFκB pathways is revealed by two-dimensional liquid chromatography-tandem mass spectrometry proteomics analysis. Taken together, our findings provide new insights on the angiogenesis induced by HBV replication.

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