食用橄榄油中重金属元素的质谱分析

Determination of Heavy Metal Elements in Edible Olive Oil by ICP-MS

摘要:

建立了电感耦合等离子体质谱(ICP-MS)法直接测定橄榄油中Cr、Ni、As、Cd、Hg、Pb等6种重金属元素的分析方法。样品经正丙醇+二甲苯（70:30，V/V）有机溶剂稀释后直接进入ICP-MS进行分析，有机样品可以长时间保持稳定以满足多元素的测定要求，在等离子气中引入少量氧气，以防止样品溶液中的高碳在质谱采样锥锥孔沉积导致分析元素的灵敏度降低。应用碰撞/反应池技术校正了多原子离子对待测元素产生的质谱干扰，采用Rh为内标元素校正了质谱分析中的基体效应。6种重金属元素的检出限在17.58~53.81 ng/L之间，加标回收率在94.00~107.00%之间，相对标准偏差（RSD）为1.33~2.80%。

Abstract:

This paper established a simple method for the determination of Cr, Ni, As, Cd, Hg and Pb in olive oil by using inductively coupled plasma mass spectrometry (ICP-MS). The olive oil was diluted with n-propanol/xylene (70:30, V/V), then the above six heavy metal elements in the sample were analyzed directly by ICP-MS. Organic sample could keep stable in n-propanol/xylene solution for a long time in order to satisfy the multi-element determination requirement. A small amount of oxygen added into the argon gas line to prevent the deposition of carbon on the sampling cone, which might lead to the clogging of the orifice and a reduction in sensitivity. The use of octopole reaction system (ORS) eliminated the interference of polyatomic ions dramatically. The matrix effects and the instrument drift commendably calibrated with Rh as internal standard element. Under the optimal conditions, the detection limits for six heavy metal elements were in the range of 17.58~53.81 ng/L. In addition, the recoveries of standard addition were from 94.00% to 107.00% and the RSD were 1.33~2.80%.