Simultaneous analysis of Cu and Pb as ABEDTA complexes in Rhizoma coptidis by capillary electrophoresis coupled with solid phase extraction

A novel capillary electrophoresis method for simultaneous determination of Cu and Pb has been developed in this paper. Cu(II) and Pb(II) ions were reacted with ABEDTA to form complex to achieve an ideal sensitivity of heavy metal complexes. The digestion solution of Rhizoma coptidis drug sample was purified by neutral Al2O3 column chromatography and the chromatographic behavior of metal–L complexes was investigated. The calibration curve was linear in the range of 5–60 μg/mL for Cu2+ and 5–25 μg/mL for Pb2+ with the correlation coefficients 0.9970 and 0.9972 for each (n = 5). The average recoveries were 86.2% for Pb and 90.1% for Cu, while the relative standard deviations were 5.1% and 3.6% respectively. The method was successfully applied to determine Cu and Pb in R. coptidis drug samples.