Determination of Cd2+, Cr3+, Cu2+ and Zn2+ in Traditional Chinese Medicine Shuanghuanglian Oral Liquid by High Performance Capillary Electrophoresis

Background: The safety and level of heavy metal ions in the traditional Chinese medicine has become an important topic. Most of the metal ions are carcinogens and lead to serious health concerns by producing free radicals. It is of great significance to develop simple and effective methods to determine heavy metal ions. The aim of this paper is to develop a CE-indirect UV method for the analysis of the four heavy metal ions for Chinese medicine Shuanghuanglian oral liquid. Methods: The alternative CE method for separation and test of metal ions was developed in this paper, which can help control the safety and level of heavy metal ions in traditional Chinese medicine Shuanghuanglian oral liquid. And the developed HPCE method showed superior analytical performance, including high sensitivity and good selectivity. Results: The experimental conditions of the CE separation method were: 5s hydrodynamic injection at 0.5 psi, 20 kV applied voltage, and UV detection at 218 nm. The results show that the migration time of all the four heavy metal ions was less than 6 min. The calibration curves for four heavy metal ions were linear in the range of 0.5-35 μg mL-1 with linear correlation coefficients of 0.9984-0.9999. The limits of detection were in the range of 0.08-0.61 μg mL-1 along with the recoveries of 93.0% to 109.5%. Conclusion: A simple, rapid and sensitive HPCE method has been developed to separate four heavy metal ions including Cd2+, Cr3+, Cu2+ and Zn2+ in traditional Chinese medicine Shuanghuanglian oral liquid. The comprehensive analysis performance is satisfactory. The proposed HPCE method provides shorter analysis time and lower detection limit. The results demonstrated that the developed CE method can be potentially applied as an good alternative for quality control of TCM.