离子色谱-电感耦合等离子体质谱法测定野生食用菌中6种砷形态

Determination of 6 arsenic species in wild edible mushrooms by inductively coupled plasma mass spectrometry

目的建立离子色谱-电感耦合等离子体质谱法(IC-ICP-MS)同时测定野生食用菌中砷甜菜碱(As B)、砷胆碱(As C)、二甲基砷(DMA)、一甲基砷(MMA)、亚砷酸As(Ⅲ)、砷酸As(Ⅴ)6种砷形态的方法。方法野生食用菌中砷形态用1%稀硝酸70℃超声提取1 h,离心后取上清液,残渣重复提取2次后合并上清液混匀,上清液经0.22μm滤膜过滤后通过阴离子色谱柱Dionex Ion Pac^(TM) AS7分离,2 mmol/L和100 mmol/L碳酸铵为流动相梯度洗脱,以电感耦合等离子质谱仪检测75As,外标法定量。结果 6种砷形态在0.5μg/L^50μg/L浓度线性关系良好,相关系数均为0.999 5,6种砷形态检出限为2μg/kg^8μg/kg,3个不同加标水平平均回收率为92.4%~109.1%,相对标准偏差<7%。结论该方法具有灵敏度高、准确性好的特点,可用于野生食用菌中砷形态检测分析。

Objective To develop ions chromatography coupled with inductively coupled plasma mass spectrometry（ IC-ICP-MS） method for the simultaneous determination of 6 arsenic species[As B,As C,DMA,MMA,As（ Ⅲ）,As（ Ⅴ） ].Methods The dried mushroom powder was ultrasonic extracted by 1% HNO3 at 70 ℃ for an hour. After centrifugation,the supernatant was collected and the residue was extracted two times,then the supernatants were mixed together. The chromatographic separation was achieved on an Dionex Ion PacTMAS7 column using a mobile phase consisting of 2 mmol/L and 100 mmol/L ammonium carbonate by gradient elution,six arsenic species were detected by ICP-MS,and quantified by external standard method. Results The linear relationships were good,and the correlation coefficient（ r） was 0. 999 5,when the concentrations of the6 arsenic species were within 0. 5 μg/L-50 μg/L. The detection limits of 6 arsenic species were within 2 μg/kg-8 μg/kg. The recovery efficiency of 92. 4%-109. 1% could be obtained under 3 spike levels and the RSDs were less than 7%. Conclusion The method possesses the advantages of good sensitivity and accuracy,and it is suitable for the simultaneous determination of 6 arsenic species in wild edible mushrooms.