title: Simultaneous determination of mandelic acid enantiomers and phenylglyoxylic acid in urine by high-performance liquid chromatography with precolumn derivatization.
abstract: A reversed-phase HPLC method for the simultaneous quantitative determination of mandelic acid enantiomers (MA) and phenylglyoxylic acid (PGA) in urine is described. MA and PGA were extracted with ethyl acetate from urine at acidic pH and derivatized with S-(-)-1-(1-naphthyl) ethylamine. A ZORBAX SB-C(18) column (250 mm x 4.6mm i.d., 5 microm, Agilent, USA) was used with a mobile phase composed of methanol-10 mmol/L phosphate buffer [pH 2.5 (65:35, v/v)] at a flow-rate of 0.8 ml/min. Detection was set at UV wavelength of 254 nm. The mean absolute recoveries were 94.2%, 91.9%, 92.5% and 86.3% for S-MA, R-MA, PGA and salicylic acid (I.S.), respectively. The intra- and inter-day precisions determined at three different concentrations ranged from 2.8% to 4.8%, 0.7% to 7.7% and 1.3% to 6.8%, respectively. The lower limits of detection for MA enantiomers and PGA in urine were 1 microg/ml and the lower limits of quantification were 5 microg/ml (R.S.D.<10%, n=5). The method has been applied to determine the urinary excretion of MA enantiomers and PGA from Sprague-Dawley rats after orally administered with styrene.
authors.affiliation: Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310031, PR China.
authors.forename: Jin-Zhao
authors.initials: JZ
authors.lastname: Wang
authors.forename: Xiang-Jun
authors.initials: XJ
authors.lastname: Wang
authors.forename: Yi-Hong
authors.initials: YH
authors.lastname: Tang
authors.forename: Shui-Jie
authors.initials: SJ
authors.lastname: Shen
authors.forename: Yin-Xiu
authors.initials: YX
authors.lastname: Jin
authors.forename: Su
authors.initials: S
authors.lastname: Zeng
mesh_terms: D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006038:Glyoxylates / Q000652:urine*; D008297:Male; D008333:Mandelic Acids / Q000737:chemistry / Q000652:urine*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D006038:Glyoxylates; D008333:Mandelic Acids; C012482:phenylglyoxylic acid; C037938:mandelic acid