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目的建立电感耦合等离子体质谱法(ICP—MS)直接提取测定大批量样品的乳粉样品中硒的方法。方法样品不经传统的酸消化法而是采用四甲基氢氧化铵及双氧水对奶粉样品进行碱水解处理,直接超声提取,通过微孔滤膜过滤,用电感耦合等离子体质谱仪进行测定。结果通过对乳粉标准物质及各种类型的配方乳粉的实际检测,得到方法检出限0.05μg/L,奶粉样品按0.5 g取样量计算方法检出限为0.10μg/kg,方法线性范围0μg/L~500μg/L,相关系数(r)优于0.999,方法加标回收率在98.4%~111.6%之间,相对标准偏差RSD(%)均<5.0%,方法的各指标结果均令人满意。结论本方法操作简便快捷,线性范围宽,灵敏度高,准确可靠,优于传统的检测方法,适用于大批量乳粉样品中硒含量的测定。
Objective To establish a direct method for the determination of selenium in milk powder samples by inductively coupled plasma mass spectrometry (ICP-MS). Methods The samples were subjected to alkaline hydrolysis using tetramethylammonium hydroxide and hydrogen peroxide without traditional acid digestion. The samples were directly extracted by ultrasonic and filtered through a microporous membrane filter. The samples were determined by inductively coupled plasma mass spectrometry. Results The detection limit of the method was 0.05μg / L by the actual test of milk powder standard substance and various types of formula milk powder, and the detection limit of the milk powder sample was 0.10μg / kg according to 0.5g sampling method. The linear range The relative standard deviations (RSDs) were all less than 5.0% (RSD (%)). The results of the methods were all as high as 0.999 μg / L, People are satisfied. Conclusion The method is simple and fast, wide linear range, high sensitivity, accurate and reliable. It is superior to the traditional detection methods and is suitable for the determination of selenium content in large quantities of milk powder samples.