悬浮液进样石墨炉原子吸收光谱法测定乳粉中痕量铬

摘要

Objective To establish a method for the direct determination of chromium in milk powder dissolved by water and triton using Graphite Furnace Atomic Absorption Spectrometry(GF-AAS).Methods Using NH4H2PO4as matrix modifier could reduce the temperature of atomization and solve the trailing phenomenon. The loss in ashing step could be lower using optimized step of drying and ashing procedure in graphite furnace temperature program.Results During the range line of 0~30μg/L, the correlation coefficient was 0.9995. At the same time, the detection limit was 4μg/kg. The results showed that using the method ofdetermination of chromium in milk powder standards, the value of recovery was 98.9% with RSD (n=6) 3.0%. Ten batches of milk powder were determined by using this method, all the results were less than 0.1mg/kg. There was no significant difference between the national standard and this method.Conclusion This method was simple, high sensitive and environmental, and it was applicable to determine the trace chromium of milk powder and liquid milk accurately.%目的：建立了乳粉加水和曲拉通溶解,利用石墨炉原子吸收光谱法直接测定铬的检测方法。方法采用 NH4H2PO4作基体改进剂,降低原子化温度,解决拖尾现象；在石墨炉升温过程中采用分步干燥和分步灰化优化升温程序,降低灰化损失。结果铬浓度在0~30μg/L 范围内具有良好的线性关系,相关系数为0.9995；方法检出限为4μg/kg；利用该法测定乳粉考核样品中铬的含量,回收率为98.9%,相对标准偏差(n=6)为3.0%；利用本法对10批奶粉进行测定,结果均低于0.1mg/kg,与国标方法无显著差异。结论该法简便快速、灵敏度高、污染少,适用于乳粉以及液体乳中痕量铬的快速准确测定。