电感耦合等离子体质谱法测定乳制品中硒含量

本研究建立以甲醇为基体改进剂内标校正外标定量的电感耦合等离子体质谱法检测乳与乳制品中微量元素硒的含量。本研究采用微波消解前处理方法,使用电感耦合等离子体质谱仪的碰撞反应模式,内标中添加甲醇溶液为基体改进剂,通过分析微量元素硒的6个同位素的灵敏度和线性相关性,确定选择质量数 _⁷⁸Se 测定乳制品中的硒。同时用Minitab 中的DOE实验设计进行分析,采用 _⁷²Ge元素作内标补偿基体效应,最终以 7.5 %(V/V)的甲醇作为基体改进剂,有效的控制了硒的回收率；本研究的方法检出限为固体样品0.00737mg/kg,液体样品0.00264mg/kg,5种不同基质样品的精密度(RSD,n=6)在2.0 %～6.1 %之间,加标回收率为 81.1 %～117 %。该检测方法快速简便,精密度高,准确性好,也具有较高的灵敏度,可为乳及乳制品中微量元素硒的测定提供参考。

Determination of selenium in dairy products by inductively coupled plasma mass spectrometry

Objective To establish a method for the determination of selenium in milk and dairy products by inductively coupled plasma mass spectrometry (ICP-MS). Methods The microwave digestion method was used. The collision reaction mode of ICP-MS was used. Methanol solution was added to the internal standard as matrix modifier. The sensitivity and linear correlation of 6 isotopes of selenium were analyzed to determine the selected mass number of 78Se in dairy products. At the same time, the DOE experimental design in Minitab was used for analysis, and 72Ge element was used as internal standard to compensate matrix effect. Results The correlation coefficient of the method was above 0.999. The limit of detection of solid samples was 0.00737 mg/kg, and that of liquid samples was 0.00264 mg/kg. The precision of five different matrix samples was 2.0%?6.1% (n=6), and the recoveries were 81.1%?117%. Conclusion The method is rapid, simple, accurate and sensitive, which can provide reference for the determination of trace element selenium in milk and dairy products.