A Factorial Design and Simplex Optimization of a Bismuth Film Glassy Carbon Electrode for Cd(II) and Pb(II) Determination

This work presents the use of a fractional two-level factorial design to determine the influence of different factors involved in the development of the square-wave anodic stripping voltammetry method. A fractional factorial design of eight different electrodes using a bismuth film glassy carbon electrode (BiFGCE) was formulated, and the impact of the factors on the analytical performance of the electrodes was determined. The impact of six factors (deposition potential, deposition time, potential step, amplitude, frequency, and the concentration of Bi(III)) was tested for Cd(II) and Pb(II) determination. Next, simplex optimization was carried out to improve the electroanalytical performance of the BiFGCE. The objective of simplex optimization was to simultaneously obtain a low limit of quantification, a wide linear concentration range, high sensitivity, high accuracy, and good precision for the new BiFGCE developed. By employing the latter approach, an optimization criterion was improved by several orders of magnitude. Moreover, the possible interference effect of different species was tested using two optimized BiFGCE. Furthermore, a real sample analysis of tap water with two optimized BiFGCEs was also carried out.