Simultaneous Determination of Lead and Copper by Carbon Paste Electrode Modified with Pyruvaldehyde BIS(N,N′-Dibutyl Thiosemicarbazone)

Abstract

ABSTRACT A carbon paste electrode modified with a new chelating reagent pyruvaldehyde bis(N,N′-dibutyl thiosemicarbazone) (TPSB) for the voltammetric simultaneous determination of lead (II) and copper (II) was described by anodic stripping voltammetry (ASV). The metal ion is accumulated on the surface of the modified electrode by the chelating effect of the modifier in the carbon paste, and then is determined by ASV after the potential reduction at-1.0V. For a 5-min accumulation time, two linear calibration graphs were obtained in the range 2x10−6 to 8x10−8 M and 1.57x10−7 to 1.26x10−9 M for lead and copper, respectively. The detection limits are 2x10−9 M for lead and 1.57x10−10 M for copper for 20 minutes of accumulation time. A chemical and electrochemical renewal allows the use of a single modified electrode in multiple analytical determination over several days. For twenty preconcentration—determination—renewal cycles, the peak current of voltammetry of analyte decreases slightly. Many other ions have no or little effect on the determination. The mechanism of electrode reaction was also discussed.