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建立电感耦合等离子体质谱(ICP-MS)法直接测定食用矿物油中重金属元素的分析方法。矿物油采用二甲苯稀释后直接进入ICP-MS分析其中的Cr、Ni、As、Cd、Hg、Pb等6个重金属元素的含量,通过在等离子气中引入少量氧气,可有效避免样品溶液中高浓度碳冷凝沉积在接口和离子透镜上导致分析元素灵敏度的降低,应用碰撞/反应池(CRC)技术校正了多原子离子对待测元素产生的质谱干扰,采用Ge、Rh、Ir为混合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0.15～0.67 ng/L之间,加标回收率在98.75%～104.31%,相对标准偏差(RSD)为1.62%～4.97%。方法可实现食用矿物油中6种重金属元素的准确分析。
A method for the direct determination of heavy metal elements in edible mineral oil by inductively coupled plasma mass spectrometry (ICP-MS) was established. The content of six heavy metal elements such as Cr, Ni, As, Cd, Hg and Pb in mineral oil diluted with xylene directly into ICP-MS analysis can be effectively avoided by introducing a small amount of oxygen into the plasma gas The condensation of carbon on the interface and the ion lens led to a decrease in the sensitivity of the analytical element. The collision / reaction cell (CRC) technique was used to correct the mass spectral interference generated by the polyatomic ions on the elements to be measured. Ge, Rh and Ir were used to correct for the mixed internal standard element Matrix effect in mass spectrometry analysis. The detection limits of six heavy metal elements ranged from 0.15 to 0.67 ng / L, the recoveries were 98.75% -104.31%, and the relative standard deviations (RSDs) were 1.62% -497%. The method can realize accurate analysis of six kinds of heavy metal elements in edible mineral oil.