Rivera-Núñez Zorimar, Linder Aaron M, Chen Bin, Nriagu Jerome O
Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
Anal Methods. 2011 May 1;3(5):1122-1129. doi: 10.1039/c0ay00601g. Epub 2011 Mar 30.
Many methods that have been used to speciate arsenic metabolites in urine are unable to adequately resolve the chromatographic peaks for arsenite (As[iii]) and arsenobetaine (AsB). We present a High Performance Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometry (HPLC-ICP-MS) method that has been optimized to reliably measure the following six arsenic species in human urine: As[iii], arsenate (As[v]), monomethylarsonous acid (MMA[iii]), monomethylarsonic acid (MMA[v]), dimethylarsinic acid (DMA[v]) and AsB. The method was evaluated with regards to changes in mobile phase, accuracy and precision. The ability to quantify the six species in a given sample depended on the low detection limits of the method-0.06 μg L for AsB, 0.11 μg L for As[iii], 0.08 μg L for DMA[v], 0.12 μg L for MMA[v] and 0.15 μg L for As[v]. The procedure was used to measure the six arsenic species in urine samples from 387 individuals in southeast Michigan who are chronically exposed to slightly elevated levels of arsenic in their drinking water. The DMA[v] was detected in 99.2% of samples, AsB in 98.2%, MMA[v] in 73.4%, As[iii] in 45.0%, and As[v] in 27.1%. No MMA[iii] was detected even in samples analyzed within 6 hours after collection. The results raise some doubt as to whether MMA[iii] is a significant metabolite in urine of people exposed to arsenic concentrations below 20 μg L in their drinking water.
许多用于对尿液中的砷代谢物进行物种鉴定的方法，都无法充分解析亚砷酸盐（As[iii]）和砷甜菜碱（AsB）的色谱峰。我们提出了一种高效液相色谱 - 电感耦合等离子体质谱联用（HPLC - ICP - MS）方法，该方法经过优化，可可靠地测量人尿中的以下六种砷物种：As[iii]、砷酸盐（As[v]）、一甲基亚砷酸（MMA[iii]）、一甲基砷酸（MMA[v]）、二甲基砷酸（DMA[v]）和AsB。对该方法在流动相变化、准确度和精密度方面进行了评估。在给定样品中对这六种物种进行定量的能力取决于该方法的低检测限——AsB为0.06 μg/L，As[iii]为0.11 μg/L，DMA[v]为0.08 μg/L，MMA[v]为0.12 μg/L，As[v]为0.15 μg/L。该程序用于测量密歇根州东南部387名长期接触饮用水中砷含量略有升高的个体尿液样本中的六种砷物种。在99.2%的样本中检测到了DMA[v]，98.2%的样本中检测到了AsB，73.4%的样本中检测到了MMA[v]，45.0%的样本中检测到了As[iii]，27.1%的样本中检测到了As[v]。即使在采集后6小时内分析的样本中也未检测到MMA[iii]。这些结果让人怀疑MMA[iii]是否是饮用水中砷浓度低于20 μg/L的人群尿液中的一种重要代谢物。
