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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。
OBJECTIVE To establish a method for the direct determination of chromium by using graphite furnace atomic absorption spectrometry with the addition of milk powder and triptorelin. Methods NH4H2PO4 was used as matrix modifier to reduce the atomization temperature and solve the trailing phenomenon. In the process of graphite furnace heating, step-by-step drying and step-by-step ashing were used to optimize the temperature increasing program to reduce the ashing loss. Results Chromium concentration in the range of 0 ~ 30μg / L had a good linearity with a correlation coefficient of 0.9995. The detection limit of the method was 4μg / kg. The chromium content in milk samples was determined by this method. The recovery rate was 98.9% The relative standard deviation (n = 6) was 3.0%. The results of 10 batches of milk powder measured by this method were lower than 0.1mg / kg, which showed no significant difference from the national standard method. Conclusion The method is simple, rapid, sensitive and less polluting. It is suitable for the rapid and accurate determination of trace chromium in milk powder and liquid milk.