原子吸收光谱测定味精中锌元素不同前处理方法的比较

Comparison of different pretreatment methods for determination of zinc in monosodium glutamate by atomic absorption spectroscopy

采用火焰原子吸收光谱法测定味精中锌的含量,研究了湿法消解、微波消解和干法消解等试验条件,以及不同消解方法中所使用不同的酸和加酸的时机。标准曲线在0.1μg/mL~0.8μg/mL浓度范围内线性良好,相关系数大于0.999。三种方法中湿法和微波消解结果精密度和准确度都较好,适用于味精中锌的测定。结果表明其中微波消解效果最好,而在湿法消解和微波消解中使用盐酸进行消化效果最佳。使用盐酸进行湿法消解的加标相对标准偏差为0.9%~3.8%,回收率在98.2%~106.7%。使用盐酸进行微波消解的加标相对标准偏差为1.3%~3.3%,回收率在90.9%~101.2%。干法消解回收率则不稳定,不太适用于味精中锌的测定。

Flame atomic absorption spectroscopy was used to determine the content of zinc in monosodium glutamate.The experimental conditions such as wet digestion,microwave digestion and dry digestion,and different acid used in different digestion methods and the timing of adding acid were investigated.The established method exhibited good linearity in the range of 0.1μg/mL~0.8μg/mL with a correlation coefficient of more than 0.999.The precision and accuracy of wet and microwave digestion were better in three methods,suitable for the determination of zinc in monosodium glutamate.The results showed that microwave digestion was the best among them,while the best digestion was performed by using hydrochloric acid in wet digestion and microwave digestion.The relative standard deviation of using hydrochloric acid for wet digestion was 0.9%~3.8%.The recovery rate was 98.2%~106.7%.The relative standard deviation of using hydrochloric acid for microwave digestion was 1.3%~3.3%,and the recovery rate was 90.9%~101.2%.While the recovery rate of dry digestion was unstable and not suitable for the determination of zinc in monosodium glutamate.