New Procedure for Detecting Pesticides By Activating SERS Properties of Screen-Printed Electrodes

Abstract

The lack of sensitivity traditionally associated with Raman spectroscopy has limited the development of new analytical applications. However, enhancement of Raman intensity due to the electrochemical surface-enhanced Raman scattering (EC-SERS) effect is an interesting alternative to overcome this limitation. Although different analytical methods have been used in the detection of pesticides, the complicated instrumentation and the long procedures employed lead to the development of new and easy methodologies for quick detection.EC-SERS methodology proposed in this work for the detection of different pesticides uses metal SPEs as SERS substrates but also includes a preconcentration step as essential stage. After that, SPEs are electrochemically activated by cyclic voltammetry. Sensitivity of the methodology proposed in this work provides interesting results that allows us the detection of different pesticides. Particularly interesting are the results obtained in the detailed analysis of Raman bands of thiram and imidacloprid. Their characteristic bands allow the detection of 2.4 ppb thiram and 25 ppb imidacloprid.Figure 1. Raman spectra of thiram, imidacloprid, malathion and chlorpyrifos obtained by EC-SERS procedure using metal SPE. Figure 1