Lindh Christian H, Littorin Margareta, Amilon Asa, Jönsson Bo A G
Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, University Hospital, Lund, Sweden.
Rapid Commun Mass Spectrom. 2008;22(2):143-50. doi: 10.1002/rcm.3348.
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.
苯氧乙酸是广泛使用的除草剂。苯氧乙酸的毒性存在争议，但在动物研究中已表明，高剂量接触具有肝毒性和肾毒性。已发现不同物种间存在毒性效应差异，狗尤其易感。本研究描述了一种使用液相色谱/三重四极杆质谱法（LC/MS/MS）分析人尿中4-氯-2-甲基苯氧乙酸（MCPA）及其代谢物4-氯-2-羟甲基苯氧乙酸（HMCPA）、2,4-二氯苯氧乙酸（2,4-D）和2,4,5-三氯苯氧乙酸（2,4,5-T）的方法。尿样经酸水解处理以降解可能的结合物。采用固相萃取进行样品制备。在负离子模式下使用选择反应监测（SRM）进行分析。使用[（2）H（3）]标记的MCPA和2,4-D作为内标对苯氧乙酸进行定量。该方法在0.05 - 310 ng/mL尿液范围内呈线性，批内精密度为2 - 5%。较低浓度范围的批间精密度在6 - 15%之间，较高浓度范围在2 - 8%之间。检测限确定为0.05 ng/mL。发现尿中的代谢物在-20℃储存期间稳定。为验证苯氧乙酸作为接触生物标志物的有效性，该方法应用于人体口服接触MCPA、2,4-D和2,4,5-T的实验。两名健康志愿者单次口服剂量各200μg苯氧乙酸，随后在接触后72小时进行尿样采集。接触后，90%至101%的剂量在尿中回收。在女性受试者中，23%的MCPA以HMCPA形式排泄，男性受试者中为17%。
