Determination of Total Arsenic, Soluble Arsenic, Total Mercury and Soluble Mercury for a Realgar and Cinnabar-containing Traditional Chinese Medicine Compound Niuhuang Xiaoyan Capsule by Semi-bionic Extraction- ICP-MS

Background: Compound Niuhuang Xiaoyan capsule is a realgar and cinnabar-containing traditional Chinese medicine, the contents of total arsenic and total mercury are found over regulation defined limits. However, only small amounts of arsenic in realgar and mercury in cinnabar are dissolved in the gastric juice, so the determination of soluble arsenic and soluble mercury is more significant than that of total arsenic and total mercury in Compound Niuhuang Xiaoyan capsule. Objective: To study the contents of total arsenic, total mercury, soluble arsenic and soluble mercury in Compound Niuhuang Xiaoyan capsule. Methods: Microwave digestion and semi-bionic extraction were used to pretreat the samples of Compound Niuhuang Xiaoyan capsule, and the inductively coupled plasma mass spectrometry method was established to determine the contents of total arsenic, total mercury, soluble arsenic and soluble mercury in Compound Niuhuang Xiaoyan capsule. The accuracy of the established method was further evaluated by using a certified standard reference material prepared from dried citrus leaves (GBW10020(GSB-11)). Results: The spiked recoveries were within 95-105 %. The R.S.D% of repeatability (N=6) and precision (N = 6) were below 5.0 %. The correlation coefficients of linear (R) for arsenic and mercury were both above 0.998. The limits of quantification (LOQ) were below 0.1 μg/L. The contents of As and Hg were defined in the dried citrus leaves and very near to the standard values provided by the manufacturer. The established method was applied for the analysis of three batches of Compound Niuhuang Xiaoyan capsule produced by three different manufacturers successfully. Insufficient realgar or cinnabar was formulated in some Compound Niuhuang Xiaoyan capsule samples. Conclusion: The analysis showed that the contents of soluble arsenic and soluble mercury in artificial gastric juice were significantly less than that of total arsenic and total mercury in Compound Niuhuang Xiaoyan capsule. The results provided a reference for further study on the toxicology and pharmacokinetics of Compound Niuhuang Xiaoyan capsule.