微波消解-石墨炉原子吸收光谱法测定茶叶中镉

Microwave Digestion-graphite Furnace Atomic Absorption Spectrometry Determination of Cadmium in Tea

目的建立快速、准确、灵敏的微波消解——石墨炉原子吸收光谱法,用于茶叶中镉的测定。方法样品中加入硝酸进行微波消解,加入磷酸二氢铵作为基体改进剂以改善峰形和灵敏度,用石墨炉原子吸收光谱法进行镉含量的测定。结果在优化的最佳消解条件和检测条件下,该方法具有很好的灵敏度,试验的RSD为1.5%~4.1%,回收率为96.3%~97.7%,检出限为0.012μg/L。结论该方法具有灵敏度高、检出限低,共存干扰少、稳定性好、回收率高等特点,是测定茶叶中镉含量的可靠方法。

Objective To establish a rapid,accurate,and sensitive microwave digestion-graphite furnace atomic absorption spectrometry,used for the determination of cadmium in tea. Methods Microwave digestion sample in nitric acid,adding ammonium dihydrogen phosphate matrix modifier to improve the sensitivity and peak shape,by graphite furnace atomic absorption spectrometry for the determination of cadmium content. Results In the optimization of the optimum digestion conditions and testing conditions,this method had good sensitivity,the precision of the test was 1.5%-4.1%,the recovery was 96.3%-96.3%,the detection limit was 0.12μg/L. Conclusion This method which has high sensitivity,low detection limit,coexistence of less interference,good stability,high recovery rate,etc,is a reliable method for determination of cadmium content in tea.