Detection of multi-class pesticide residues with surface-enhanced Raman spectroscopy

The excessive use of pesticides disturbs the natural balance in the environment, creates resistance to pesticides and leads to water and food contamination. Therefore, the implementation of fast, robust and cost effective techniques for the monitoring of pesticides is required. In this work surface-enhanced Raman spectroscopy (SERS) was used for the detection of four common pesticides: atrazine, simazin, irgarol, and diuron. SERS is nowadays considered an effective technique for detection of various analytes in low concentration. Sensitivity of the SERS method depends on the type of substrate that can be either a colloidal solution of metal nanoparticles (NPs) or a metal surface with a suitable nanostructured topology. Here, we have investigated the application of silver nanospheres and silver nanoprisms as SERS substrates in pesticides detection. Colloids with spherical NPs were produced by chemical reduction while Ag nanoprisms were prepared by reducing silver nitrate with borohydride (with citrate as a stabilizing agent) and stirring under a UV lamp for 4 and 10 h. The SERS results have shown that, in the presence of synthesized NPs, it was possible to detect millimolar concentrations of aforementioned pesticides with the exception of diuron.