Determination of dimethoate in water by cathodic stripping square‐wave voltammetry

Abstract

This article describes the direct determination of the pesticide dimethoate in river water in an alkaline medium through cathodic stripping voltammetry. By employing an alkaline media and accumulation potential of 30 mV, reduction peak appears at -0.7 V. The detection limit is 1 ng m1-I.

Determination of Dimethoate in Olive Oil by Adsorptive Stripping Square‐Wave Voltammetry

“…This behavior has been described in literature [14,15] but some discrepancies about the involved processes are encountered. On the other hand, the studies described here also show differences with those in [15], regarding to the accumulation conditions. To determine dimethoate in olive oil, an extraction method and posterior clean-up procedure have been developed.…”

“…Regarding to the peak to potentials close to À 0.700 V, it is not related to mercaptoacetic acid, but it seems to be due to the formation of other compounds containing sulfur as mentioned in [15].…”

“…On the other hand, it has been found three methods for the determination of dimethoate by polarography [13,14] and cathodic stripping square-wave voltammetry [15], but the determinations are carried out in industrial formulations [13] and in water samples [14,15].…”

“…The authors explain the second peak as due to the R À S À anion which is characterized because it reacts easily with Hg 2þ resulting in the insoluble compound (R À S) 2 Hg which originates a mercury reduction peak to potentials close to À 0.700 V [15]:…”

“…Therefore, according to literature [15] it would be necessary to preconcentrate at positive potentials to get the formation of Hg…”