Le X C, Ma M
Department of Public Health Sciences, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Anal Chem. 1998 May 1;70(9):1926-33. doi: 10.1021/ac971247q.
Increasing concerns over human exposure to arsenic and more stringent environmental regulations require rapid determination of trace levels of individual arsenic species, which presents an analytical challenge. We describe a method that is capable of speciating nanogram-per-milliliter levels of arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) within 3 min. Speciation of two common inorganic species in drinking water, As(III) and As(V), is complete in 1.5 min. The method is based on a combination of fast high-performance liquid chromatography (HPLC) separation of arsenic species on 3-cm HPLC guard columns and the sensitive detection of arsenic hydride by atomic fluorescence spectrometry. Detection limits for the four arsenic species in urine samples are 0.4-0.8 ng/mL. This simple method allows for the direct speciation of arsenic present in natural water samples and in human urine samples from the general population, with no need of any sample pretreatment. Our results from the determination of arsenic species in urine and water standard reference materials are in good agreement with the certified values of total arsenic concentration. The method has been successfully applied to speciation studies of metabolism of arsenosugars following the consumption of arsenosugar-containing mussels by human volunteers. Speciation of arsenic in urine samples collected from four volunteers after the ingestion of musseles reveals significant increases of DMAA concentration, resulting from the metabolism of arsenosugars. These results suggest that the commonly used biomarkers for assessing human exposure to inorganic arsenic, which are based on the determination of urinary arsenite, arsenate, MMAA, and DMAA, are not reliable when arsenosugar-containing seafood is ingested.
人们对人类接触砷的担忧日益增加，同时环境法规也更加严格，这就要求快速测定痕量水平的各个砷物种，这带来了一项分析挑战。我们描述了一种能够在3分钟内对每毫升纳克水平的亚砷酸盐（As(III)）、砷酸盐（As(V)）、一甲基胂酸（MMAA）和二甲基胂酸（DMAA）进行形态分析的方法。饮用水中两种常见无机物种As(III)和As(V)的形态分析在1.5分钟内完成。该方法基于在3厘米高效液相色谱（HPLC）保护柱上对砷物种进行快速高效液相色谱分离，并通过原子荧光光谱法对砷化氢进行灵敏检测。尿液样品中四种砷物种的检测限为0.4 - 0.8纳克/毫升。这种简单的方法能够直接对天然水样和普通人群的人类尿液样品中的砷进行形态分析，无需任何样品预处理。我们对尿液和水标准参考物质中砷物种的测定结果与总砷浓度的认证值高度一致。该方法已成功应用于人类志愿者食用含砷糖的贻贝后砷糖代谢的形态分析研究。对四名志愿者摄入贻贝后收集的尿液样品中的砷进行形态分析，结果显示由于砷糖的代谢，DMAA浓度显著增加。这些结果表明，当摄入含砷糖的海鲜时，基于测定尿中亚砷酸盐、砷酸盐、MMAA和DMAA来评估人类接触无机砷的常用生物标志物并不可靠。
