全自动石墨消解-ICP-MS法同时测定粮食和蔬菜中多种元素及健康风险评价

Simultaneous determination of multiple elements in food grains and vegetables with fully automatic graphite digestion-inductively coupled plasma mass spectrometry and health risk assessment

目的建立全自动石墨消解-ICP-MS测定粮食和蔬菜中20种元素检测方法,并对洛阳市售的粮食和蔬菜的有限量值8种元素进行健康风险评价。方法在全自动石墨仪上通过程序加入7 mL硝酸+1 mL高氯酸消解样品,用2%硝酸(V/V)定容到25 mL,联合ICP-MS同时测定20种元素,与微波消解-ICP-MS法比较差异性。采集90份市售粮食和蔬菜,根据国标限值和8种重金属靶标危害系数(THQ)和综合危害指数(TTHQ)值进行健康风险评价。结果20种元素工作曲线相关系数r均>0.9990,检出限在0.001~0.395 mg/kg。平行测定标物大米(n=11),相对标准偏差(RSD)均<5%,检测结果均在标准物质认定值范围内,且与微波消解-ICP-MS法比较,差异无统计学意义(Z=-0.805,P=0.421)。90份样品汞检出率最低(6.7%),平均含量前10位元素依次为钾、镁、钙、钠、铁、铝、锌、锰、锶、铜,均未超标。大米THQ、小麦和蔬菜THQ、TTHQ值均<1。结论全自动石墨消解仪与ICP-MS联用适合大批粮食和蔬菜中多种元素同时测定。

Objective To establish a fully automatic graphite digestion-inductively coupled plasma mass spectrometry(ICP-MS)for determination of 20 elements in food grains and vegetables,and to evaluate the health risk of 8 elements in market-sold food grains and vegetables with limited quantity values in Luoyang City.Methods Nitric acid(7 mL)and perchloric acid-digested samples(1 mL)were added in the fully automatic graphite device;and then,the solution was added to 25 mL with 2%nitric acid(V/V).A total of 20 elements were determined using ICP-MS,and compared with microwave digestion-ICP-MS.A total of 90 market-sold food grains and vegetables were collected,and the health risk was evaluated according to the limits of the national standard and the target hazard quotient(THQ)and total target hazard quotient(TTHQ)of 8 heavy metals.Results The correlation coefficients(r)for the working curves of 20 elements were all>0.9990,and the detection limits were 0.001 to 0.395 mg/kg.Rice samples(n=11)were set as the parallel substance with a relative standard deviation(RSD)of all<5%,and the determination results were all within the range of certified values of standard substances,and comparable with the results determined using the microwave digestion-ICP-MS(Z=-0.805,P=0.421).The lowest detection of heavy metals was mercury in 90 samples(6.7%),and the 10 highest average contents included potassium,magnesium,calcium,sodium,iron,aluminum,zinc,manganese,strontium and copper,which all did not exceed the standard.In addition,the THQ of rice was<1,and the THQ and TTHQ of wheat and vegetables were all<1,while the TTHQ of rice was 1.63.Conclusions Automatic graphite digestion instrument in combined with ICP-MS is feasible for simultaneous determination of multiple elements in large-scale food grains and vegetables,and much attention should be given to the risk of heavy mental contamination in market-sold rice in Luoyang City.