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Analysis of phenoxyacetic acid herbicides as biomarkers in human urine using liquid chromatography/triple quadrupole mass spectrometry
Author(s) -
Lindh Christian H.,
Littorin Margareta,
Amilon Åsa,
Jönsson Bo A. G.
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3348
Subject(s) - chemistry , chromatography , mass spectrometry , urine , triple quadrupole mass spectrometer , liquid chromatography–mass spectrometry , selected reaction monitoring , tandem mass spectrometry , biochemistry
Phenoxyacetic acids are widely used herbicides. The toxicity of phenoxyacetic acids is debated, but high‐level exposure has been shown to be hepatotoxic as well as nephrotoxic in animal studies. An inter‐species difference in toxic effects has been found, with dogs particularly susceptible. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) is described for the analysis of 4‐chloro‐2‐methylphenoxyacetic acid (MCPA), and its metabolite 4‐chloro‐2‐hydroxymethylphenoxyacetic acid (HMCPA), 2,4‐dichlorophenoxyacetic acid (2,4‐D), and 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T) in human urine. The urine samples were treated by acid hydrolysis to degrade possible conjugations. The sample preparation was performed using solid‐phase extraction. Analysis was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the phenoxyacetic acids was performed using [ 2 H 3 ]‐labeled MCPA and 2,4‐D as internal standards. The method was linear in the range 0.05–310 ng/mL urine and has a within‐run precision of 2–5%. The between‐run precision in lower concentration ranges was between 6–15% and between 2–8% in higher concentration ranges. The limit of detection was determined to 0.05 ng/mL. The metabolites in urine were found to be stable during storage at −20°C. To validate the phenoxyacetic acids as biomarkers of exposure, the method was applied in a human experimental oral exposure to MCPA, 2,4‐D and 2,4,5‐T. Two healthy volunteers received 200 µg of each phenoxyacetic acid in a single oral dose followed by urine sampling for 72 h post‐exposure. After exposure, between 90 and 101% of the dose was recovered in the urine. In the female subject, 23%, and in the male subject 17%, of MCPA was excreted as HMCPA. Copyright © 2007 John Wiley & Sons, Ltd.