Tuning of gold nanoparticles analytical applications with nitro and hydroxy benzylindole-dithiocarbamates for simple and selective detection of terbufos and thiacloprid insecticides in environmental samples

Abstract

We have tuned the applications of gold nanoparticles (Au NPs) with nitro and hydroxy benzylindole-dithiocarbamate derivatives for simple and selective colorimetric detection of terbufos and thiacloprid insecticides in environmental samples. The nitro and hydroxy benzylindole-dithiocarbamate (NBI- and HBI- DTC) derivatives are used as anchors on the surfaces of unmodified Au NPs and cause the aggregation of Au NPs induced by terbufos and thiacloprid insecticides, resulting in the red-to-blue color change and the appearance of new surface plasmon resonance peaks at 630 and 625nm in the absorption spectrum of NBI- and HBI- DTC Au NPs. On this basis, the concentrations of terbufos and thiacloprid can be visualized through the red-to-blue color change of NBI- and HBI- DTC Au NPs and quantitatively determined by UV–vis spectroscopy. Under the optimized conditions, the colorimetric systems exhibit a linear range from 0.5 to 50μM for terbufos and from 5.0 to 500μM for thiacloprid using NBI- and HBI- DTC Au NPs as probes. The detection limits (3σ/m) of 7.3×10−8 and 6.0×10−7M were achieved for terbufos and thiacloprid, respectively. Furthermore, we demonstrate the application of the approach for the analysis of terbufos and thiacloprid in environmental water and food samples, which suggests that the present method exhibits good recoveries (97.16–99.31%) and capable to identify individual terbufos and thiacloprid or mixtures of them in real samples.