HPLC-ICP-MS测定植物样品中6种砷形态化合物

通过优化色谱分离、样品前处理条件,同时对比了电感耦合等离子体质谱的标准模式(STD)、碰撞模式(KED)、氧气反应模式(Oxygen-DRC)、甲烷反应模式(Methane-DRC)的检测结果,建立了一种有效分离植物样品中砷甜菜碱(AsB)、二甲基砷酸(DMA)、亚砷酸(As(Ⅲ))、砷胆碱(AsC)、一甲基砷酸(MMA)、砷酸(As(Ⅴ))6种砷形态化合物的高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)分析方法。样品以1%HNO₃溶液为提取溶剂,90℃加热提取2.5 h,RP小柱净化,然后采用AS7阴离子交换柱分离,25~80 mmol/L(NH₄)₂CO₃溶液梯度洗脱,在STD模式下测定,6种砷形态化合物在9 min内完全分离。方法检出限为0.10~0.25μg/L,加标回收率为87.5%~117.8%,相对标准偏差(RSDs)为1.2%~1.8%。方法适用于植物样品中6种砷形态化合物的测定。

Determination of six arsenic species compounds in plant samples by HPLC-ICP-MS

After optimization of chromatographic separation and pretreatment conditions,and comparison the results of STD,KED,Oxygen-DRC and Methane-DRC mode in ICP-MS,a method for the simultaneous determination of arsenobetaine,dimethyl arsenic acid,arsenite,arsenic choline,methyl arsenic acid and arsenate was developed by high performance liquid chromatography and inductively coupled plasma mass spectrometry(HPLC-ICP-MS).The plant sample was added into 1%nitric acid solution,and then the mixture was placed on an electric heating plate and heated at 90℃for 2.5 h.After purified by the RP column,the filtrate was separated on a Dionex IonPac AS7 anion exchange column with 25-80 mmol/L ammonium carbonate as mobile phase by gradient elution.Identification and quantification were achieved by ICP-MS in STD mode and six arsenic species were separated clearly within 9 min.Under the optimized conditons,the limits of detection were 0.10-0.25μg/L for the analytes,and the recoveries ranged from 87.5%to 117.8%with relative standard deviations of 1.2%-1.8%.The developed method is suitable for the determination of arsenic species in plant samples.