Study of the electro-adsorptive behaviour of the herbicide nitralin by means of voltammetric techniques

The electroanalytical behaviour of the herbicide Nitralin has been studied by means of different voltammetric techniques. Nitralin is adsorbed on the mercury electrode and gives 2 reduction waves at -0.6 and -0.7 V versus Ag/AgCl reference electrode, for pH values > 10. The electrochemical process is irreversible and strongly influenced by pH solution. A systematic study of the several instrumental and accumulation variables affecting the stripping response was carried out using square wave (SWV; Osteryoung's method) and differential pulse voltammetry (DPV) as redissolution techniques. The limits of detection were 4.4 x 10(-10) mol l(-1) (AdS-SWV) and 3.5 x 10(-11) mol l(-1) (AdS-DPV), with variation coefficients of 4.17 and 3.90% respectively, at a concentration level of 8 x 10(-9) mol l(-1) (n = 10). A method, based on AdS-DPV, for the determination of Nitralin in ground-water is proposed. A detection limit of 8.7 x 10(-11) mol l(-1) (AdS-DPV) was reached in real samples. (C) 1997 Elsevier Science B.V.