Dithiocarbamate-calix[4]arene functionalized gold nanoparticles as a selective and sensitive colorimetric probe for assay of metsulfuron-methyl herbicide via non-covalent interactions

Abstract

In this work, a distinct demonstration of sensitive and selective colorimetric detection of metsulfuron-methyl herbicide in real samples was carried out using dithiocarbamate-p-tertbutylcalix[4]arene capped Au NPs (DTC-PTBCA-Au NPs) as a probe via host-guest (non-covalent) interactions. A careful optimization of all potential factors, the performance of the probe was successfully applied to detect metsulfuron-methyl in real samples with unique features including high selectivity, and assay with minimal volume of samples. Metsulfuron-methyl induces the aggregation of DTC-PTBCA-Au NPs via host-guest interaction, resulting red-shift in the surface plasmon resonance (SPR) absorption band accompanied by color changes which could be distinguished by the naked-eye. There is a good linearity with metsulfuron-methyl in the range of 1.0–50μM, with a detection limit of 1.9×10−7M (S/N=3). The DTC-PTBCA-Au NPs showed selective sensing performance towards metsulfuron-methyl over other herbicides, insecticides and fungicides. The percentage recovery obtained by the proposed method in real-world examples such as environmental water and food samples were 97–99% with relative standard deviation (RSD) <3%. The probe has been successfully used to detect metsulfuron-methyl in environmental water and food samples.