The electrochemical behaviour of propanil and related N-substituted amides
(acetanilide and N,N-diphenylacetamide) was studied by cyclic and square wa
ve voltammetry using a glassy carbon electrode. Propanil has been found to
have chemical stability under the established analytical conditions and sho
wed an oxidation peak at +1.27 V versus Ag/AgCl at pH 7.5. N,N-diphenylacet
amide has a higher oxidation potential than the other compounds of +1.49 V
versus Ag/AgCl. Acetanilide oxidation occurred at a potential similar to th
at of propanil, +1.24 V versus Ag/AgCl. These results are in agreement with
the substitution pattern of the nitrogen atom of the amide. A degradation
product of propanil, 3,4-dichloroaniline (DCA), was also studied, and showe
d an oxidation peak at +0.66 V versus Ag/AgCl. A simple and specific quanti
tative electroanalytical method is described for the analysis of propanil i
n commercial products that contain propanil as the active ingredient, used
in the treatment of rice crops in Portugal. (C) 2001 Elsevier Science B.V.
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