动物性海产品中砷形态分析方法的研究

目的 建立动物性海产品中砷甜菜碱(AsB)、亚砷酸盐(AsⅢ)、砷酸盐(AsⅤ)、二甲基砷酸(DMA)和一甲基砷酸(MMA)的液相色谱-在线紫外消解-氢化物发生-原子荧光光谱联用的测定方法(LC-UV-HG-AFS).方法 以90%甲醇为提取溶液,超声振荡提取后,提取液以N2浓缩至近干,加水溶解残渣后以正己烷萃取除去脂质成分,取下层清液,以超纯水定容至10 ml,过滤后进样分析;以0.2 mmol/L磷酸二氢铵(pH9.0)和20 mmol/L磷酸二氢铵(pH6.0)为流动相,梯度洗脱,以Hamilton PRPX-100柱分离,LC-UV-HG-AFS检测.结果 在给定的色谱条件下,AsB、AsⅢ、AsⅤ、DMA和MMA达到基线分离;各组分的检出限在0.0025～0.0032 mg/L之间,重复性和再现性＜10%,0.2 mg/kg添加水平的回收率＞85%;鱼、虾、贝样品中所含有的主要砷形态化合物为AsB,仅在某些贝类样品中检出微量AsⅢ和DMA;分别以定值参考物NBS 1566牡蛎组织和BCR 627金枪鱼考察总砷测定和砷形态分析的准确性,结果符合定值要求.结论 建立的LC-UV-HG-AFS方法适合于动物性海产品中砷形态化合物的特异性检测,测定结果准确可靠.

A study on arsenic speciation analysis in animal origin seafood

OBJECTIVE: To develop a method for determining arsenobetaine (AsB), arsenite (AsIII), arsenate (AsV), Monomethylarsonic acid (MMA) and Dimethylarsenic acid (DMA) with liquid chromatography (LC), on-line UV-decomposition (UV), hydride generation (HG) and atomic fluorescence spectrometry (AFS) in animal origin seafood samples. METHODS: Arsenic compounds were extracted in an ultrasonic bath with methanol-water (9:1) solvent from the animal origin seafood samples. The extracts were evaporated with N2 and dissolved in water. The solvent was extracted by hexane to remove lipids. And then, the aqueous solution was diluted to 10 ml. The extracts were filtered before analysis by LC-AFS. The mobile phase consisted of 0.5 mmol/L NH4H2PO4 (pH 9.0) and 20 mmol/L NH4H2PO4 (pH 6.0). Arsenic species were separated with an anion exchange column Hamilton PRPX-100 and gradient elution, detected by LC-UV-HG-AFS. RESULTS: The established separation condition could achieve a better separation for five arsenic species. Detection Limits (LOD) were ranged from 0.0025 to 0.0032 mg/L, AsB was the predominant arsenic species in the animal origin seafood samples. AsIII and DMA were detected in certain shellfish samples at trace level. The accuracy of total arsenic measurement was tested by the analysis of NBS 1566 (Oyster Tissue). The accuracy of arsenic species measurement was tested by the analysis of BCR 627 (Tuna Fish). The data were tallied with the certified value. CONCLUSION: Arsenic species were specifically detected by LC-UV-HG-AFS in the animal origin seafood samples.