双三元液相色谱串联ICP-MS对中国东北和西南地区的4种松茸的砷形态分析

Arsenic Speciation of Four Kinds of Tricholoma matsutakes from Northeastern and Southwestern China Using Dual-Gradient Chromatography Tandem ICP-MS

目的松茸中砷含量很高且含有不同的砷形态,包括:砷甜菜碱(AsB)、砷胆碱(AsC)、三价砷(AsⅢ)、五价砷(AsⅤ)、一甲基砷(MMA)、二甲基砷(DMA)、三甲基氧化砷(TMAO)和砷糖。然而,有机砷化合物被认为毒性较小,甚至无毒,所以总砷含量不能提供关于其毒性的全部有效信息,需分析其具体的砷酸盐形态。方法我们采用了基于HPLC耦合电感耦合等离子体质谱(ICP-MS)的优化分析方案来分析松茸中的As种类。使用含有5和100 mmol·L^(-1)的(NH_(4))_(2)CO_(3)的混合流动相,通过DionexIonPacTM AS7色谱柱与ICP-MS检测器进行目标As物种的分离。结果经过优化的HPLC色谱条件在15 min内实现了目标As物种的分离,并具有良好的分辨率。在松茸中检测到的主要砷形态是无毒的AsB。结论现行中国国家标准GB2762-2017以总砷含量为质量标准。结果表明,将无机砷含量作为质量标准可能更为合理。

OBJECTIVE Tricholoma matsutake contain high arsenic and different arsenic forms including:arsenobetaine(AsB),arsenocholine(AsC),trivalent arsenic(As Ⅲ),pentavalent arsenic(AsⅤ),monomethylarsenic(MMA),dimethylarsenic(DMA),trimethylarsenic oxide(TMAO)and arsenose.However,organic arsenic compounds are considered to be less toxic or even non-toxic,so the total arsenic content does not provide all valid information on their toxicity and needs to be analysed for its specific arsenate form.METHODS An optimised analytical protocol based on HPLC coupled with ICP-MS was used to analyse As species in Tricholoma matsutake.A mixed mobile phase containing 5 mmol·L^(-1) and 100 mmol·L^(-1) of(NH_(4))_(2)CO_(3) was used for the separation of the target As species via a DionexIonPacTM AS7 column with an ICP-MS detector.RESULTS The optimised HPLC chromatographic conditions achieved separation of the target As species within 15 minutes with good resolution.The predominant form of arsenic detected in Matsutake was the non-toxic arsenic betaine(AsB).CONCLUSIONS The existing Chinese national standard GB2762-2017 take total arsenic content as the quality standard.The results suggest that considering inorganic arsenic content as the quality standard may be more reasonable.