Optimization Central Composite Design for the Simultaneous Determination of Cd(II) ion in Fruit and Vegetable Samples by Adsorptive Stripping Voltammetry

This work describes a procedure for the simultaneous determination of cadmium in fruit and vegetable samples using adsorptive stripping voltammetry of complexes with calcon at a hanging mercury drop electrode ( HMDE) has been optimized using central composite design ( CCD). The selection of the experimental conditions was made using experimental of the influence of several parameters were studied : variations of calcon concentration, pH, accumulation potential and accumulation time. The design experiment was a central composite design with 4 factors/variables, 3 levels and 31 treatment combinations. From analysis of variance, it was decided to accept the second-order model and the independent variable, concluded that a significant effect on the response variable ( peak current). Based on data analysis with central composite design, the determination of cadmium obtained optimum conditions were : calcon concentration 0.8435 mM, pH 8.0047, accumulation potential -0.6346 Volt and accumulation time 81.85 seconds with a maximum peak current 61.8146 nA. At the optimum condition were obtained relative standard deviation 0.84%, recovery 98.88%, the linear range up to 110 mu g/L, limit of detection 1.009 mu g/L and LOQ 3.363 mu g/L. The procedure was successfully applied to the determination of cadmium in fruit and vegetable samples without prior treatment.