High throughput screening and antioxidant assay of dibenzo[a,c]cyclooctadiene lignans in modified-ultrasonic and supercritical fluid extracts ofSchisandra chinensis Baill by liquid chromatography–mass spectrometry and a free radical-scavenging method

2008 ◽  
Vol 31 (8) ◽  
pp. 1322-1332 ◽  
Author(s):  
Ming-Chih Wang ◽  
Yih-Cherng Lai ◽  
Chia-Lin Chang
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Free Radical ◽  
Supercritical Fluid ◽  
High Throughput ◽  
High Throughput Screening ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Liquid Chromatography Mass Spectrometry ◽  
Antioxidant Assay

scholarly journals Cherry-Picking in an Orchard: Unattended LC/MS Analysis from an Autosampler with >32,000 Samples Online

2006 ◽  
Vol 11 (3) ◽  
pp. 318-322 ◽  
Author(s):  
Nader Ari ◽  
Lucas Westling ◽  
John Isbell
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Throughput ◽  
High Throughput Screening ◽  
Combinatorial Libraries ◽  
Liquid Chromatography Mass Spectrometry ◽  
Standard Format ◽  
Potential Error ◽  
Ms Analysis ◽  
Cherry Picking

The 1536-well microplate format has widely supplanted the 384-well microplate format for high-throughput screening and for IC50 assays. Previously, liquid chromatography/mass spectrometry (LC/MS) analyses of such samples required manual transfers of the wells of interest from a 1536-well plate into a 384-well plate. Because this manual transfer introduced a source of potential error, it became clear that amore appropriate solutionwould be to sample directly from the 1536-well plates. Currently, commercially available 1536-well plate autosamplers are not compatible with Waters LC/MS systems. The authors have modified their CTC PAL autosampler to support injection from up to twenty-four 1536-well plates. This allows them to cherry-pick any sample from up to 36,864 wells on the autosampler. Because of its success at this Institute, sampling from 1536-well plates has not only become the preferredmethod for LC/MS analysis from IC50 plates but also become the standard format used for the handling of and the sampling from large combinatorial libraries.

scholarly journals In Vitro  Kinetic Evaluation of the Free Radical Scavenging Ability of Propofol

2012 ◽  
Vol 116 (6) ◽  
pp. 1258-1266 ◽  
Author(s):  
Weiguang Li ◽  
Yu Zhang ◽  
Yanru Liu ◽  
Feng Yue ◽  
Yiming Lu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Free Radical ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
The Body ◽  
Kinetic Evaluation ◽  
Working Solution ◽  
Radical Scavenging Ability

Background Propofol is a widely used, short-acting, and intravenously administered hypnotic agent with notable antioxidant and free radical scavenging activities. However, there are relatively few kinetic studies on the free radical scavenging ability of propofol. The goal of this study is to evaluate the kinetics of propofol scavenging 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical (ABTS(·+)). Methods The stock solution of ABTS(·+) was prepared by incubating 7 mM ABTS with 2.8 mM potassium persulfate in deionized water, and then diluted with 5 mM phosphate-buffered saline (pH 7.2) to get a working solution (36 μM ABTS(·+) and 18 μM ABTS). The reaction was monitored by measuring specific absorbance changes of ABTS and ABTS(·+) after adding 4 μM propofol (final concentration) to the working solution. The propofol-ABTS(·+) reaction products were analyzed by high-performance liquid chromatography and liquid chromatography mass spectrometry/mass spectrometry. Results Wave scanning and kinetic evaluation demonstrated that the ABTS(·+) scavenging process of propofol is relatively fast. The ABTS(·+) consumption rate by propofol is greater than the rate of ABTS formation. The degradation products of reaction between propofol and ABTS(·+) were mainly ABTS-propofol, a part of the ABTS molecule, and a combination of propofol with a part of the ABTS molecule. Conclusions Propofol scavenges ABTS(·+) with a fast and stable kinetic feature in vitro, which is useful and important for understanding propofol's antioxidant properties. The kinetic process of the free radical scavenging activity of propofol may also play a role in dynamic protection in the body.

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