The application of differential pulse cathodic stripping voltammetry in the determination of trace copper in whole blood

Abstract

Electrochemical stripping analysis is a very important and widely used tool for the trace determination of various elements and compounds. The method is based on accumulation of Cu (II) ions onto platinum electrode, followed by the reduction of the species by differential pulse cathodic stripping voltammetry. The effect of various parameters such as pH of supporting electrolyte, accumulation of potential and time, scan rate and speed of rotating electrode on the selectivity and sensitivity were studied. The best conditions were found to be pH = 6.5 potassium acetate buffer, the accumulation potential of 0 mV (vs. Ag/AgCl), the accumulation time of 50 s, rotational speed of the working electrode 1500 rpm and the scan rate of 25 mV s-1. The peak current is proportional to the concentration of copper over the range 0.53-107 ng/mL with a detection limit of 0.159 ng/mL and an accumulation time of 50 s. The developed method was validated by the analysis of reference materials certified by total blood.