title: Determination of m-hydroxymandelic acid, m-hydroxyphenylglycol and their conjugates in human plasma using liquid chromatography with electrochemical detection.
abstract: An LC method for the analysis of m-hydroxymandelic acid (MHMA) and m-hydroxyphenylglycol (MHPG) and their conjugates in human plasma was developed and validated. The method for the quantitation involved extraction of acidified plasma (subject to hydrolysis with beta-glucuronidase for 120 min with 500 units of enzyme/0.25 ml of plasma at 37 degrees C for the conjugates) with an organic phase (methyl-tert-butyl ether). Analysis of MHMA, MHPG and the internal standard (3-hydroxy-4-methoxymandelic acid) was carried out on an ODS stationary phase: 100 x 4.6 mm, 5 mu followed by a 75 x 4.6 mm, 3 mu using 1% acetonitrile in 0.1 M acetic acid as the mobile phase. An electrochemical detector operated at +1.15 V vs Ag/AgCl was employed for the detection. The standard curves were linear in the range of 10.0-250.0 ng ml-1 for MHMA and 5.0-125.0 ng ml-1 for MHPG. The limit of quantitation was 10.0 ng ml-1 for MHMA and MHPG. Acceptable accuracy and precision were obtained during the intra-batch and inter-batch analysis for both the assays.
authors.affiliation: School of Pharmacy, University of Missouri-Kansas City 64108.
authors.forename: K
authors.initials: K
authors.lastname: Gumbhir
authors.forename: W D
authors.initials: WD
authors.lastname: Mason
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D006018:Glycols / Q000097:blood*; D006801:Humans; D006868:Hydrolysis; D008333:Mandelic Acids / Q000097:blood*; D012015:Reference Standards
chemical_list: D006018:Glycols; D008333:Mandelic Acids; C024037:3-hydroxymandelic acid; C034487:3-hydroxyphenyl glycol