ICP-MS测定药用辅料硬脂酸镁中5种重金属元素的含量

Determination of 5 heavy metal elements in magnesium stearate by ICP-MS

目的建立电感耦合等离子体质谱法(ICP-MS)测定药用辅料硬脂酸镁中铅(^(208)Pb)、砷(^(75)As)、镉(^(114)Cd)、镍(^(60)Ni)、铜(^(63)Cu)5种重金属元素的含量。方法利用正交试验法优选药用辅料硬脂酸镁微波消解的最佳条件,以^(72)Ge、^(115)In、^(209)Bi为内标,采用ICP-MS同时测定5种痕量重金属元素。结果硬脂酸镁微波消解最佳条件:料液比1∶6,消解功率为400 Hz,消解时间为10 min;各元素标准曲线的线性关系良好,相关系数r在0.9999~1.0000之间;检出限为6.006~49.582μg·kg-1;加样回收率为95.0%~101.3%,标准物质测定值与标准值一致。结论本方法简单、快速、准确,可用于硬脂酸镁中痕量重金属元素铅、砷、镉、镍、铜的测定,同时为药用辅料硬脂酸镁的质量控制提供参考。

Objective To establish an inductively coupled plasma mass spectrometry（ICP-MS） method for the determination of lead, arsenic, cadmium, nickel and copper heavy metal elements in magnesium stearate. Methods Using the method of orthogonal experiment, we optimized the best condition of microwave digestion for pharmaceutical excipients magnesium stearate. Germanium（Ge）, indium（In） and bismuth（Bi） were used as the internal standard. The contents of 5 trace elements were determined by ICP-MS, and the impact of the 2 methods on the determination results was compared. Results Best microwave conditions for magnesium stearate： solid-liquid ratio was 1∶6, digestion power was 400 Hz, and digestion time was 10 min. The linear relationship standard curve of each element was good, the correlation coefficient（r） was 0.9999-1.0000, detection limit was 6.006-49.582 μg·kg^-1, recovery rate was 95.0%-101.3%. Standard substance measured values were consistent with the standard values. Conclusion This method is simple, rapid and accurate. It can be used for the determination of trace amounts of lead, arsenic, cadmium, nickel and copper in magnesium stearate, and provide reference for the quality control of magnesium stearate.