title: Simultaneous determination of gallic acid and gentisic acid in organic anion transporter expressing cells by liquid chromatography-tandem mass spectrometry.
abstract: In order to elucidate the role of organic anion transporters (OATs) in the renal elimination of gallic acid and gentisic acid, a new, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous determination of gallic acid and gentisic acid in cell lysate, using Danshensu as the internal standard (IS). After a simple liquid-liquid extraction, the analytes were detected in negative ESI mode using selected reaction monitoring. The precursor-to-product ion transitions (m/z) were 169.0→125.0, 153.1→108.0, and 196.8→135.2 for gallic acid, gentisic acid, and the IS, respectively. Chromatographic separation was achieved on a C18 column using mobile phases consisting of water with 0.1% acetic acid (A) and acetonitrile with 0.05% formic acid. (B) The total run time was 3min and calibration curves were linear over the concentrations of 0.33-2400ng/mL for both compounds (r(2)>0.995). Good precision (between 3.11% and 14.1% RSD) and accuracy (between -12.7% and 11% bias) was observed for quality controls at concentrations of 0.33 (lower limit of quantification), 1, 50, and 2000ng/mL. The mean extraction recovery of gallic acid and gentisic acid was 80.7% and 83.5%, respectively. Results from post-column infusion and post-extraction methods indicated that the analytical method exhibited negligible matrix effects. Finally, this validated assay was successfully applied in a cellular uptake study to determine the intracellular concentrations of gallic acid and gentisic acid in OAT expressing cells.
authors.affiliation: Department of Pharmaceutics, Virginia Commonwealth University, Richmond, VA 23298, USA. Electronic address: wangl4@vcu.edu.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Halquist
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Sweet
mesh_terms: D000818:Animals; D016466:CHO Cells; D002853:Chromatography, Liquid / Q000379:methods*; D006224:Cricetinae; D003412:Cricetulus; D004355:Drug Stability; D005707:Gallic Acid / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D005841:Gentisates / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D042541:Intracellular Space / Q000737:chemistry / Q000378:metabolism; D016014:Linear Models; D051379:Mice; D029362:Organic Anion Transporters, Sodium-Independent / Q000378:metabolism*; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D005841:Gentisates; D029362:Organic Anion Transporters, Sodium-Independent; D005707:Gallic Acid; C010925:2,5-dihydroxybenzoic acid
keywords: Cell lysate; LC–MS/MS; Matrix effects; Organic solute carrier; Phenolic acids; SLC22