Effective determination of clomazone and oxyfluorfen in aqueous samples by differential pulse stripping voltammetry

Abstract

Two novel types of electrochemical sensors were obtained by chemical deposition of Pt and MoO2 nanoparticles onto multi walled carbon nano tubes (MWCNT) and used for determination of frequently used pesticides clomazone and oxyfluorfen in aqueous media via differential pulse stripping voltammetry (DPSV). Clomazone was determined in 0.1 M phosphate buffer solution at pH 7.0 in the concentration range 0.61-20.56 ng cm-3, with LOQ = 0.61 and LOD = 0.38 ng cm-3. Oxyfluorfen was determined with good reproducibility (RSD <2.4%) in the concentration range 2.5-34.5 ng cm-3, with r = 0.99 and a LOQ of 1.5 ng cm-3. Results were in the same range measured by HPLC/DAD, which was used as comparative method. Structural characterization of the dopped MWCNT performed by Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron (HR-TEM), and X-ray crystallography revealed a preserved MWCNT structure decorated with well dispersed species of the platinum and MoO2 nanoparticles.