原子荧光法测定甘草及甘草制剂中砷含量及不同消解方法比较

目的：探讨不同消解方法在原子荧光法测定甘草及甘草制剂中砷含量的应用，并按建立的方法测定了11批不同产地的甘草饮片及3 批不同厂家甘草制剂的砷含量。方法：比较硝酸- 高氯酸消解法、硝酸- 硫酸- 高氯酸消解法、微波消解法三种前处理方法的回收率，确定采用微波消解法对样品进行前处理，加硫脲- 抗坏血酸溶液还原5 价砷为3 价砷进行测定，检测波长为193.7 nm，灯电流为60 mA 狭缝宽度0.4 nm。结果：微波消解法测砷精密度良好，RSD 为0.8%（n=6），线性范围为0~10 μg·L^-1，相关系数为0.999 5，检出限为0.01 mg·kg^-1，平均回收率为93.1%。并采用建立的方法测得11 批甘草饮片砷含量为0~0.13 mg·kg^-1，3 批甘草制剂砷含量为0.046~1.29 mg·kg^-1。结论：本法可用于甘草及甘草制剂中砷含量的测定。

Objective:To explore different digestion methodsin determination of As in Glycyrrhizae Radix et Rhizoma and its preparations in atomic fluorescence spectrometry(AFS),and determine arsenic in 11batches of Glycyrrhizae Radix et Rhizoma from different origins and 3 batches of preparations from different manufacturers. Methods:Recovery of three methods were compared,including nitric acid-perchloricacid digestion,nitric acid-sulfuric acid-perchloricacid digestion and microwave digestion.The samples were digested by microwave digestion,combined with thiourea-ascorbic acid solution,which reduced As(Ⅴ)to As(Ⅲ).The detection wavelength was 193.7 nm for arsenic with the lamp current at 60 mA,and the slit-width was 0.4 nm.Results:The method exhibited good precision with RSD of 0.8%(n=6);the linear range was found at 0-10 μg·L^-1.The linear correlative coefficient was 0.999 5.The limit of detection is 0.01 mg·kg^-1.The average recovery was 93.1%.The method was then applied to detemining the content of arsenic in the 11 batches of Glycyrrhizae Radix et Rhizoma and 3 batches of preparations.The contents of arsenic in Glycyrrhizae Radix et Rhizoma were between 0-0.13 mg·kg^-1.The contents of arsenic in preparations were between 0.046-1.29 mg·kg^-1.Conclusion:The established method can be used for the determination of arsenic in Glycyrrhizae Radix et Rhizoma and preparations.