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目的考察超声提取法、微波消解法、人工胃液浸提法3种不同的前处理方法对乳粉中的痕量铅和镉含量测定结果的影响。方法分别采用超声提取法、微波消解法、人工胃液浸提法对1种乳粉质控样和3种乳粉考核样进行前处理,采用电感耦合等离子体质谱仪测定。结果采用超声提取法、微波消解法、人工胃液浸提法,铅的方法检出限分别为2.45μg/kg、4.90μg/kg和2.45μg/kg,镉的方法检出限分别为0.3μg/kg、0.6μg/kg和0.3μg/kg。3种方法铅检测的相对标准偏差(RSD)分别为2.0%~3.7%、2.2%~3.1%和2.0%~4.0%;镉检测的RSD分别为0.4%~2.8%、1.1%~2.6%和0.3%~2.6%,重复性均良好。采用3种前处理方法乳粉质控样和考核样中铅和镉的测定结果均在参考值范围内,结果均为满意。结论 3种前处理方法均适用于乳粉中痕量铅和镉的含量测定。
Objective To investigate the effects of ultrasonic extraction, microwave digestion and artificial gastric juice extraction on the determination of lead and cadmium in milk powder by three different pretreatment methods. Methods One kind of milk powder quality control sample and three kinds of milk powder evaluation samples were pretreated by ultrasonic extraction, microwave digestion and artificial gastric juice extraction respectively, and were determined by inductively coupled plasma mass spectrometry. Results The detection limits were 2.45μg / kg, 4.90μg / kg and 2.45μg / kg by ultrasonic extraction method, microwave digestion method, artificial gastric juice extraction method and lead method. The detection limits of cadmium were 0.3μg / kg, 0.6 μg / kg and 0.3 μg / kg. The relative standard deviations (RSDs) of the three methods were 2.0% -3.7%, 2.2% -3.1% and 2.0% -4.0% respectively. The RSDs of cadmium detection were 0.4% -2.8%, 1.1% -2.6% and 0.3% ~ 2.6%, repeatability are good. The results of determination of lead and cadmium in the milk powder quality control sample and evaluation sample using the three pretreatment methods are within the reference range and the results are satisfactory. Conclusion The three pretreatment methods are suitable for the determination of trace amounts of lead and cadmium in milk powder.