Analysis of phenoxyacetic acid herbicides as biomarkers in human urine using liquid chromatography/triple quadrupole mass spectrometry

Abstract

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.

Assessment of long-term and recent pesticide exposure among rural school children in Nicaragua

“…Urine samples were hydrolysed and extracted using a mixed-mode solid-phase extraction cartridge. Extracts were analysed by high-performance liquid chromatography–tandem mass spectrometry using selected reaction monitoring in the negative ion mode 23 24. The limits of detection (LOD) were 0.05 ng/ml for 2,4-D, 0.2 ng/ml for 3-PBA and 1 ng/ml for TCPY.…”

Concentrations and temporal trends in pesticide biomarkers in urine of Swedish adolescents, 2000–2017

“…The measured concentrations only reflect exposure within the past 24 h and are probably associated with very recent intake of food, since these compounds have short biological half-lives [38,48]. Furthermore, the absolute measured urinary concentrations of each compound can be difficult to compare because the metabolism and toxicokinetic parameters of the compounds vary.…”

“…Our lab has previously conducted human exposure experiments for CCC [40], OH-PYM [38], OH-TBZ [58], ETU [39], 2,4-D, and MCPA [48] in which volunteers were administered a single oral doses equal to, or 50% of, the accepted daily intake (ADI). The measured urine concentrations from the exposed volunteers in these studies were up to 1000 times higher than those found in Swedish adolescents.…”

Enhanced photocatalytic–biological degradation of 2,4 dichlorophenoxyacetic acid

“…Many studies were reported that 2,4-D may cause cytogenetic damage in human lymphocytes, 5 hepatotoxicity, nephrotoxicity, 6 promotion of lung tumors and non Hodgkin's lymphoma. 20,21 Therefore, this compound was selected as a model of toxic chemical pollutants relevant to Egypt where this study is conducted.…”

“…2 2,4-Dichlorophenoxyacetic acid (2,4-D) is the third-most widely used herbicide all over the world and is still applied in Egypt although its use is restricted by the European Community and in many countries. 3,4 The health hazards of 2,4-D to humans include that it may induce a cytogenetic damage in human lymphocytes, an irreversible eye damage, hepatotoxicity and nephrotoxicity, 5,6 besides being classified by the International Agency for Research on Cancer (IARC) as class 2B carcinogen to humans.…”