A method for the simultaneous determination of Pb(II), Cd(II), and Zn(II) at low gL−1 concentration levels
by sequential injection analysis-anodic stripping voltammetry (SIA-ASV) using screen-printed carbon
nanotubes electrodes (SPCNTE) was developed. A bismuth film was prepared by in situ plating of bismuth
on the screen-printed carbon nanotubes electrode. Operational parameters such as ratio of carbon nanotubes
to carbon ink, bismuth concentration, deposition time and flow rate during preconcentration
step were optimized. Under the optimal conditions, the linear ranges were found to be 2–100gL−1 for
Pb(II) and Cd(II), and 12–100gL−1 for Zn(II). The limits of detection (Sbl/S = 3) were 0.2gL−1 for Pb(II),
0.8gL−1 for Cd(II) and 11gL−1 for Zn(II). The measurement frequency was found to be 10–15 stripping
cycle h−1. The present method offers high sensitivity and high throughput for on-line monitoring of trace
heavy metals. The practical utility of our method was also demonstrated with the determination of
Pb(II), Cd(II), and Zn(II) by spiking procedure in herb samples. Our methodology produced results that
were correlated with ICP-AES data. Therefore, we propose a method that can be used for the automatic
and sensitive evaluation of heavy metals contaminated in herb items.