Microwave digestion polarography for determining seven trace elements in Salvia Miltiorrhiza Root and compound Salvia Militiorrhiza Root injection simultaneously

Abstract

The sensitive second derivative waves of Cu(II), Pb(II), Cd(II), Ni(II), Zn(II), Fe(II) and Mn(II), forming in the substrate solution (pH=9.26) consisting of ammonia, ammonium chlorid, gelatin and ascorbic acid were researched. The peak potentials of the polarographic waves of the seven ions are at about −0.48, −0.63, −0.79, −1.04, −1.28, −1.44 and −1.60 V respectively. Combining with microwave technique, a new method for the simultaneous determination of the seven trace elements in Chinese traditional medicine was developed. The method is easy to operate, rapid, simple and convenient. When the signal-to-noise rate equals 3, the detection limits of Cu, Pb, Cd, Ni, Zn, Fe and Mn are 4.2 × 10⁻³, 5.3 × 10⁻³, 2.1 × 10⁻³, 5.8 × 10⁻⁴, 3.0 × 10⁻³, 7.7 × 10⁻⁴ and 1.1 × 10⁻³ μg/mL respectively. Well linear relationships exist between the concentrations and the peak currents when Cu, Pb, Cd, Ni, Zn, Fe and Mn concentrations are within 8.5 × 10⁻³−10, 9.7 × 10⁻³, 4.5 × 10⁻³−10, 1.2 × 10⁻³−10, 6.4 ×10⁻³−10, 1.5 × 10⁻³−10 and 2.8 × 10⁻³−10 μg/mL, respectively. The method has been used to the simultaneous determination of the seven trace elements in Salvia Miltiorrhiza Root and compound Salvia Miltiorrhiza Root injection, the relative standard deviations(RSDs) of the Cu, Pb, Cd, Ni, Zn, Fe and Mn in the two medicines are 3.9% and 5.8%, 4.0% and 4.1%, 4.3% and 5.7%, 4.9% and 5.3%, 4.4% and 4.7%, 3.5% and 4.0%, 0.51% and 2.8%, respectively; the comparisons of the determination results with the values obtained by the standard method indicate that the presented method has very well veracity.

Keywords

derivative polarographic wave / microelement / Salvia Miltiorrhiza Root / compound Salvia Miltiorrhiza Root injection