Analysis of phenoxyacetic acid herbicides as biomarkers in human urine using liquid chromatography/triple quadrupole mass spectrometry.
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 degrees 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 microg 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.
Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, University Hospital, Lund, Sweden. christian.lind@med.lu.se
Christian H
CH
Lindh
Margareta
M
Littorin
Asa
A
Amilon
Bo A G
BA
Jönsson
D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000493:pharmacokinetics / Q000652:urine; D015084:2,4-Dichlorophenoxyacetic Acid / Q000493:pharmacokinetics / Q000652:urine; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives / Q000493:pharmacokinetics / Q000652:urine*; D000284:Administration, Oral; D000328:Adult; D015415:Biomarkers / Q000652:urine*; D002853:Chromatography, Liquid / Q000379:methods*; D005260:Female; D006540:Herbicides / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D015415:Biomarkers; D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid; D015085:2,4,5-Trichlorophenoxyacetic Acid; D008456:2-Methyl-4-chlorophenoxyacetic Acid