Voltammetric determination of the herbicides nitralin and oryzalin in agricultural formulations, vegetables and grape juice samples

A sensitive method for the determination of the herbicides nitralin and oryzalin by adsorptive stripping voltammetry (AdSV) at a hanging mercury drop electrode (HMDE) (pH 6.0) was described. The cyclic voltammograms demonstrate the adsorption of these compounds at the mercury electrode. A symmetric study of the various operational parameters that affect the stripping response was carried out by differential pulse voltammetry. With an accumulation potential of −0.5 V and a 80 s accumulation time, the limit of detection was 2.47 × 10−8 mol/L and 1.5 × 10−8 mol/L, the relative standard deviation (n = 10), correlation coefficient values 1.14%, 0.998, 1.48%, 0.999 at concentration levels of 8.3 × 10−8 mol/L to 1.5 × 10−6 mol/L and 2 × 10−8 mol/L to 1.0 × 10−5 mol/L for both compounds. The degree of interference of some other pesticides on the differential pulse adsorptive stripping signal for nitralin and oryzalin was evaluated. Finally the proposed method was applied for determination of nitralin and oryzalin in agricultural formulations, vegetables and grape juice samples.