大米中总砷与无机砷含量检测与结果分析

Detection and analysis of total arsenic and inorganic arsenic in rice

目的建立大米中无机砷的常规检测方法,监测大米中总砷与无机砷含量。方法用电感耦合等离子体质谱法测定大米中总砷含量,液相原子荧光法测定大米中无机砷含量。分层随机采集赣榆区市售大米样品进行砷含量检测。结果总砷在0.50~50.0μg/L范围内线性关系良好(r=1.000),方法检出限为2.5μg/kg,定量限为7.5μg/kg,加标回收率为85.0%~110.0%,相对标准偏差(RSDs)为3.7%~6.8%。无机砷在2.00~20.0μg/L范围内线性关系良好(r值均>0.998),检出限为0.02mg/kg,定量限为0.05mg/kg,加标回收率为91.2%~107.0%,RSDs为4.4%~6.8%。采集20份市售大米样品进行检测,总砷含量为0.04~0.23mg/kg,平均(0.132±0.052)mg/kg;无机砷含量为0.01~0.16mg/kg,平均(0.082±0.025)mg/kg。检出无机砷样品中,无机砷含量占总砷的43.6%~89.1%,平均(62.4±9.6)%。市售大米As(Ⅲ)、As(Ⅴ)检出率分别为95.0%、5.0%,通过大米摄入无机砷的量远远低于人可耐受摄入量。结论赣榆区大米中无机砷多以As(Ⅲ)存在,对人体健康的风险处于较低水平。

Objective To monitor and analyze arsenic in rice;to monitor the content of total arsenic and inorganic arsenic in rice.Methods The total arsenic content in rice was determined by inductively coupled plasma mass spectrometry.The inorganic arsenic content in rice was determined by liquid atomic fluorescence spectrometry.Market sold rice samples were collected by stratified sampling method in Ganyu district for arsenic analysis.Results The linear relationship of total arsenic was good in the range of 0.5-50.0μg/L(r=1.000),LOD was 2.5μg/kg,LOQ was 7.5μg/kg,the spiked recovery rates were 85.0%-110.0%,RSDs were 3.7%-6.8%.The linear relationship of inorganic arsenic was good in the range of 2.00-20.0μg/L(r>0.998),LOD was 0.02 mg/kg,LOQ was 0.05 mg/kg,the spiked recovery rates was 91.2%-107.0%,RSDs were 4.4%-6.8%.Total arsenic content of 20 market sold rice samples were in the range of 0.04-0.23 mg/kg,with average of(0.132±0.052)mg/kg;the inorganic arsenic content was in the range of 0.01-0.16 mg/kg,with average of(0.082±0.025)mg/kg.For samples positive of arsenic detection,the inorganic arsenic accounted for 43.6% to 89.1% of the total arsenic,with the average of(62.4±9.6)%.The detection rate of As(Ⅲ)and As(Ⅴ)was 95.0% and 5.0%,respectively.The intake amount of inorganic arsenic through rice was much lower than the tolerable intake.Conclusion Inorganic arsenic in rice in Ganyu district exists mostly as As(Ⅲ),and the risk to human health is at a low level.