电感耦合等离子体质谱(ICP-MS)法测定化妆品中的总硒量

Determination of Total Selenium in Cosmetics by Inductively Coupled Plasma Mass Spectrometry(ICP-MS)

目的本文对化妆品中总硒含量的测定方法进行探讨。方法采用HNO_3-H_2O_2-H_2O微波消解,锗内标在线校正基体效应,外标法ICPMS定量测定化妆品中的总硒。样品经微波消解处理成溶液后,经气动雾化器以气溶胶的形式进入氩气为基质的高温射频等离子体中,经过蒸发、解离、原子化、电离等过程,转化为带正电荷的正离子,经离子采集系统进入质谱仪,在质谱仪中根据质荷比进行分离,质谱信号强度与进入质谱检测器中的离子数成正比,进行元素的定量分析检测。结果硒在0.0~100.0ng·mL^(-1)浓度范围内与峰强度呈现良好线性关系(r2=1),平均加样回收率为83.09%,RSD为3.8%(n=9);检测限为0.04ng·g^(-1)。结论 ICP-MS具有宽线性范围,低检出限,高灵敏度及良好的准确度和精密度等优点,能适应不同的样品基体,是高效可行的方法,适用于市售化妆品中总硒的常规测定。

OBJECTIVE To discuss the determination of the total selenium content of cosmetics, and provide a reference method for the determination of total selenium in cosmetics. METHODS HNO3-HEO2-H2O used in mi- crowave digestion as sample pretreatment reagents, Ge as internal standard online to eliminate the influence of matrix effects, and the total selenium in cosmetics was quantitatively detected by ICP-MS with external standard. The sample was pretreated into solution after microwave digestion, then into the high-temperature argon matrix RF plasma in form of an aerosol formation by pneumatic nebulizer, after evaporation, dissociation, atomization, and ionization process, turned into positively charged positive ions, then into the mass spectrometer by ion collection system. The elements were separated in the mass spectrometer according to their mass-charge ratio;and the mass signal intensity was pro- portional to the number of ions into the mass spectrometer. The signal intensity was proportional to the element con- centration, and then quantitatively detected by comparison with the standard series. RESULTS There showed a good linear relationship between the ion intensity and selenium concentration in the range of 0. 0 - 100. 0ng·mL^-1 with the value of r^2 = 1, the detection limits of the method was 0. 04ng·g^-1, and the average recovery rate was 83.09% with the RSD of 3.8% （n = 9）. CONCLUSION The determination method of total selenium in cosmetics by ICP-MS with good accuracy and precision, high sensitivity, low detection limit, and wide linear range, which can adapt to different sample matrix, and sample preparation by microwave digestion method is a feasible and efficient Method.