نتایج جستجو برای: lc esi ms

تعداد نتایج: 144390  

Journal: :avicenna journal of phytomedicine 0
cheruthazhakkat sulaiman centre for medicinal plants research, arya vaidya sala kottakkal-676503, kerala, india sivadasan pillai geetha centre for medicinal plants research, arya vaidya sala kottakkal-676503, kerala, india balachandran indira centre for medicinal plants research, arya vaidya sala kottakkal-676503, kerala, india

objective: ipomoea mauritiana is used in both ayurveda and folk medicine systems. the tuberous roots are known to be diuretic, depurative, carminative, and anthelmintic. the objective of the current study was to identify phenolic antioxidants from i. mauritiana using spectrophotometric and lc-ms analysis. materials and methods: an activity-guided fractionation and purification process was used t...

Journal: :Drug discoveries & therapeutics 2013
T Santa

Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) has been frequently utilized for the sensitive and selective determination of the trace level compounds in biological samples. In LC/ESI-MS/MS, chemical derivatization is sometimes used to enhance the detection sensitivity of the analytes. This review presents an overview of the derivatization rea...

Journal: :Forensic science review 2001
Y Yinon

Liquid chromatography/mass spectrometry (LC/MS), combining good separation characteristics with highly specific and sensitive detection, is the method of choice for forensic trace analysis of explosives. Principles of operation and instrumentation of several LC/MS interface/ionization modes are described. Among the various LC/MS interfaces and ionization modes, electrospray ionization (ESI)-LC/...

Journal: :Journal of the American Society for Mass Spectrometry 1991

Journal: :Drug discoveries & therapeutics 2007
T Santa O Y Al-Dirbashi T Fukushima

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESIMS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is frequently used to enhance the MS/MS detectability. The derivatization improves the separation and ionization efficiency. Moreover, the generated derivatives give par...

Journal: :Rapid communications in mass spectrometry : RCM 2002
Filip Cuyckens Magda Claeys

Different reversed-phase liquid chromatography (LC) columns of conventional dimensions were coupled to an ultraviolet photodiode array detector (UV-DAD) and a magnetic sector-type spectrometer, equipped with an electrospray ionization (ESI) source, by a laboratory-made flow splitter. A mixture of three flavonoid-O-glycosides was employed to examine the effects of the solvent composition, the fl...

Journal: :Mass spectrometry reviews 2006
Lutz Alder Kerstin Greulich Günther Kempe Bärbel Vieth

This overview evaluates the capabilities of mass spectrometry (MS) in combination with gas chromatography (GC) and liquid chromatography (LC) for the determination of a multitude of pesticides. The selection of pesticides for this assessment is based on the status of production, the existence of regulations on maximum residue levels in food, and the frequency of residue detection. GC-MS with el...

Journal: :Analytical chemistry 2011
Klaus Faserl Bettina Sarg Leopold Kremser Herbert Lindner

In this study we have evaluated the suitability of a sheathless capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) interface with a porous tip as the nanospray emitter for use in peptide analysis. A positively charged capillary coating and 0.1% formic acid as background electrolyte were used for separation upstream from mass spectrometry characterization. The influe...

Journal: :Journal of chromatography. A 2009
Risto Kostiainen Tiina J Kauppila

The most widely used ionization techniques in liquid chromatography-mass spectrometry (LC-MS) are electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). All three provide user friendly coupling of LC to MS. Achieving optimal LC-MS conditions is not always easy, however, owing to the complexity of ionization processes and t...

2015
Zahir H. Alshehry Christopher K. Barlow Jacquelyn M. Weir Youping Zhou Malcolm J. McConville Peter J. Meikle Per Bruheim

Lipidomic approaches are now widely used to investigate the relationship between lipid metabolism, health and disease. Large-scale lipidomics studies typically aim to quantify hundreds to thousands of lipid molecular species in a large number of samples. Consequently, high throughput methodology that can efficiently extract a wide range of lipids from biological samples is required. Current met...

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