Abstract: By analyzing some factors involved in the determination of lead in milk powder by inductively coupled plasma mass spectrometry (ICP-MS) such as containers and reagents used, an ultrasonic cleaning method was established to effectively reduce the blank value. The method gave a detection limit of 0.005 mg/kg, which was much lower than that (0.02 mg/kg) of traditional methods. The recoveries of samples spiked at concentration levels of 0.005–0.015 mg/kg ranged from 86.9% to 119.0% with relative standard deviations (RSDs) of 3.1%–12.3%, meeting the requirements for methodological validation. Hence, the method proved to be overall feasible and suitable for the detection of lead in milk powder with reduced detection limit.

Key words: inductively coupled plasma mass spectrometry; lead; detection limit; ultrasonic cleaning

摘要： 对电感耦合等离子体质谱法检测铅的检出限进行研究，通过对实验过程中所用器皿、试剂等因素进行分?析，建立超声清洗处理方式，有效降低空白值，使电感耦合等离子体质谱仪法测定乳粉中铅的检出限由0.02 mg/kg降?低到0.005 mg/kg。当铅的添加水平为0.005～0.015 mg/kg时，样品的加标回收率为86.9%～119.0%，相对标准偏差为?3.1%～12.3%，满足方法学验证要求，说明了整体方案的可行性。降低检出限后的方法适用于乳粉中铅的检测。

关键词: 电感耦合等离子体质谱；铅；检出限；超声清洗