微波消解-火焰原子吸收光谱法测定玉米面中的铜、锌和铁

Determination of Cu,Zn and Fe in Maize Flour with Microwave Digestion-Flame Atomic Absorption Spectroscopy

实验采用微波消解系统消解玉米面样品,将样品置于密闭容器内,加入一定量的硝酸和过氧化氢,放在微波炉内进行消解。详细考察了微波消解溶剂、消解时间、消解功率和消解压力对消解效果的影响,采用正交实验设计确定了微波消解的最佳工作参数。用火焰原子吸收光谱法测定玉米面中铜、锌和铁的含量,其相对标准偏差分别为1.99%、0.92%和2.10%(n=6),平均加标回收率分别为97.5%、102.9%和98.7%。与常压消解法的测定结果进行比较,测定值吻合,准确度和精密度均优于传统方法。

A microwave digestion system with nitric acid and hydrogen peroxide was proposed for the digestion of maize flour samples. The influence of type of acid and different digestion program were studied. The optimum parameters for microwave digestion were established by cross experiment and the copper, zinc and iron in samples were determined by flame atomic absorption spectroscopy（FAAS）. The relative standard deviations（n=6）are 1.99%,0.92% and 2. 10% with the mean recoveries of 97.5%, 102.9% and 98. 7%, respectively. Compared with the atmospheric digestion, the developed method provides the same determination results, while better performance in terms of accuracy and precision.