电感耦合等离子体质谱法(ICP-MS)测定牙膏和化妆品中的锶和其它8种元素

Determination of strontium and other elements in toothpastes and cosmetics by inductively coupled plasma mass spectrometer(ICP-MS)

目的:采用合适的样品前处理方法和电感耦合等离子体质谱法(ICP-MS)测定牙膏和化妆品中的锶和其它元素铅、镉、砷、铬、银、钡、镍和硒.方法:选择微波消解法、酸湿式消解法、干式消解法和直接硝酸超声浸提法对样品进行前处理,对比这几种方法的结果.优化仪器测定参数以适应此类样品测定.测定方法的线性范围、相关系数、检出限、精密度、加标回收率、标准物质测定等,探讨相关结果的影响因素.结果:本法采用线性范围锶为0～50μg/ml,其它元素为0～500 ng/ml,相关系数大于0.9990,方法检出限锶44ng/g、铅9 ng/g、镉19 ng/g、砷150 ng/g、铬35 ng/g、银7.5 ng/g、钡12.5 ng/g、镍18 ng/g、硒340 ng/g,样品测定11次所有元素相对标准偏差小于4.5%,加标回收率在82%～115%之间,标准物质的元素测定值在标准值范围之内.结论:用ICP-MS同时测定牙膏和化妆品中的9种元素,具有良好的准确度和精密度,灵敏度高,检出限低,线性范围宽,元素之间的干扰少,能适应不同样品基体,样品前处理采用微波消解法,是高效可行的方法.

Objective：To establish a suitable sample- pretreatment method and an ICP -MS method for the determination of strontium and other elements such as lead, cadmium, arsenic, chromium, silver, barium, nickel and selenium in toothpastes and cosmetics. Methods： Four sample - pretreatment procedures including microwave digestion, block digestion, ash digestion and supersonic extraction were used to digest samples or extract elements. Results by these four pretreatments were compared. To adjust the instrument operation condition for such applications, tuning parameters were optimized. Concentration ranges and their correlativity, limit of detection, precision, spike recoveries, and reference materials with certified values were tested. Relative impact factors were discussed. Results：Concentration ranges used in this method, Sr was 0-50μg/ml, other dements were 0-500 ng/ml. Their correlativity was good（ r 〉 0. 9990）. The detection limits were, Sr 44 ng/g, Pb 9 ng/g, Cd 19 ng/g, As 150 ng/g, Cr 35 ng/g, Ag 7. 5 ng/g, Ba 12. 5 ng/g, Ni 18 ng/g, Se 340 ng/g. The relative standard deviations （RSD%） of 11 tests of samples were lower than 4. 5%. The average spike recoveries were between 82% and 115%. The analytical results of reference materials matched to the certified values. Conclusion：This method was showed to be good precision and accuracy, high sensitivity, low detection limit, broad concentration ranges, low interference between dements and be suitable for different toothpastes and cosmetics matrix. It was showed this was an efficient ICP - MS method to determine strontium and other 8 dements in toothpastes and cosmetics with microwave digestion.