湿法消化-氢化物原子荧光光谱法测定奶粉中砷和锡的含量研究

Simultaneous detection of arsenic and stannum in milk powder by wet digested hydride-generation atomic fluorescence spectrometry

目的建立湿法消化-氢化物原子荧光光谱法同时测定奶粉中砷和锡的含量。方法奶粉试样经湿法消化后,以硫脲-抗坏血酸为还原掩蔽剂,在酸性介质中与硼氢化钾反应,用双道AFS-8230原子荧光光度计同时测定试样中的砷和锡,优化的方法条件为:光电倍增管负高压270V,锡灯电流60mA、砷灯电流60mA,载流介质为0.5%硫酸。结果砷的检出限为0.0696μg/L,相对标准偏差为0.95%,低、中、高浓度加标回收率分别为97.0%、101.0%、99.9%;锡的检出限为0.7611μg/L,相对标准偏差为2.73%,低、中、高浓度加标回收率分别为91.4%、94.8%、100.0%。结论湿法消化-氢化物原子荧光光谱法同时测定奶粉中砷和锡的检出限、精密度和准确度能满足分析要求,具有灵敏、稳定、准确的优点,达到了快速测定的目的。

Objective To establish a method for simultaneous detection of arsenic(As)and stannum(Sn)in milk powder by wet digested hydride-generation atomic fluorescence spectrometry(HG-AFS).Methods Milk powder sample was wet digested,reacted with potassium borohydride in the acidic medium,the content of As and Sn was determined by AFS-8230double-channel atomic fluorescence spectrometry.The negative high voltage of photomultiplier was 270Vand the lamp current was 60mA for both As and Sn.Results The limit of detection was 0.0696μg/L for As and 0.7611μg/L for Sn with the relative standard deviation of 0.95%and 2.73%,respectively.The recovery rates of low,medium and high concentration were 97.0%,101.0%and 99.9%for As and were 91.4%,94.8%and 100.0%for Sn.Conclusions The limit of detection,precision and accuracy of wet-digested HG-AFS meet the requirement for simultaneous determination of As and Sn in milk powder and it is stable,accurate,sensitive and fast.