福建花蛤中的砷形态的阴离子交换色谱-ICP-MS测定方法

Determination of arsenic speciation in Fujian clam by anion exchange chromatography-ICP-MS

为了解福建花蛤砷摄入的安全性,采用密闭微波辅助萃取方式,优化了提取剂组成、提取剂体积与花蛤质量的剂料比对福建花蛤各形态砷化合物总浓度提取的影响;采用阴离子交换色谱-电感耦合等离子体质谱(AEC-ICP-MS)联用技术,优化了砷甜菜碱(AsB)、三价砷[As(Ⅲ)]、二甲基砷[DMA(Ⅴ)]、一甲基砷[MMA(Ⅴ)]和五价砷[As(Ⅴ)]5种形态砷化合物的色谱条件。结果表明:当以18.2 MΩ的超纯水作为提取剂,超纯水体积和花蛤质量的剂料比为100mL/g,微波加热温度和时间分别为120℃和15min时,提取的总砷浓度最高。在1.00mmol/L(NH_4)_2CO_3洗脱1.5min后,改用pH=9.50的10.00mmol/L(NH_4)_2HPO_4进一步进行梯度洗脱,上述5种形态砷化合物被完全分离开来。在福建花蛤富集的砷形态中,95%以上是有机砷,无机砷含量远低于GB 2762—2012和NY 5073—2006规定的最高无机砷限量标准,无机砷摄入风险不高。

To know the uptake safety of arsenic（As）from Fujian clam,the effects of the extracting solvent composition and the ratio of extracting solvent volume to Fujian clam powder mass on the extraction of As speciation by closed microwave assisted extraction（MAE）were investigated.The effects of the chromatographic conditions on the separation of arsenobetaine（AsB）,arsenite[As（Ⅲ）],dimethylarsinic acid[DMA（Ⅴ）],monomethylarsonic acid[MMA（Ⅴ）]and arsenate[As（Ⅴ）]by anion exchange chromatography inductively coupled plasma mass spectrometry（AEC-ICP-MS）were studied.The results show that the total extracted concentration of arsenic species is the highest when 18.2 MΩdoubly deionized（DDI）water is used as the extracting solvent,the ratio of water volume to clam mass is 100mL/g,the microwave temperature and heating time is 120 oC and 15 min,respectively.Five arsenic compounds are completely separated after they are eluted for 1.5min by 1.00mM（NH_4）_2CO_3,then followed by the gradient elution of 10.00mM（NH_4）_2HPO_4（pH 9.50）.More than 95% As species from Fujian clam is organic As compounds.The concentration of inorganic As compounds is much lower than the Maximum Limits（MLs）from GB 2762-2012 and NY 5073-2006,which means that there exists little inorganic As intake risk from Fujian clam.