Zusammenfassung
This paper describes the electroanalytical study of the organochlorine
pesticide endosulfan (EDS) using square-wave voltammetry. The
electrochemical behaviour showed a quasi-reversible process on a hanging
mercury drop electrode (HMDE) in acid medium attributed to reduction of
the carbon-chlorine bond. The constant of change transfer obtained for
this process was 354 s(-1). The redox mechanism was confirmed by
quantum-chemical (Density Functional Theory, DFT) studies. The optimised
experimental and voltammetric parameters were 0.04 mol L-1
Britton-Robinson buffer (pH 4.0), the pulse potential frequency of 200
s(-1), the amplitude of the pulse of 20 mV, and the height of the
potential step of 4 my. Analytical parameters such as linearity range,
equation of the analytical curves, correlation coefficients, detection
and quantification limits, recovery values, precision, and accuracy were
obtained. The procedure was applied to the analysis of pesticide in
complex samples: sugar cane, tomato, and raw natural waters. The
recovery values demonstrated that the proposed methodology is suitable
for determining EDS in such samples. The results indicated that the
proposed procedure is stable and sensitive, with good reproducibility,
and no complex procedure was necessary for sample preparation. The
development of this electroanalytical procedure is therefore
appropriate, as it provides adequate sensitivity and reliable
methodology. (C) 2013 Elsevier B.V. All rights reserved.
Nutzer