A brief review of recent advances in surface-enhanced Raman spectroscopy and microfluidics technology for the ultrasensitive detection of pesticides.

Abstract

The pesticide is any substance used to prohibit, destroy, or control pests, such as insects, fungus, rodents or, undesirable plant species that cause damage during crop production and storage. There are a lot of traditional methods to detect pesticides, among them gas chromatography (GC), high-performance liquid chromatography (HPLC), and their combinations with ultraviolet (UV) or mass spectroscopy. Nevertheless, these conventional techniques have several limitations, involving complicated pre-treatment steps, requiring expensive instruments, operational difficulty, lack of instrument portability, and difficulties in real-time monitoring. Surface-enhanced Raman spectroscopy (SERS) is one of the current leading techniques widely applied for the ultrasensitive detection of pesticides molecules. SERS takes advantage to combine the high specificity of Raman scattering with the signal amplification of electromagnetic enhancement provided by the excitation of surface Plasmon resonances in metallic nanostructures, together with the charge transfer mechanisms established between metal surfaces and analytes. In this brief review, types of classification of pesticides that can be classed have been reported. These classifications can provide valuable information on the chemistry of pesticides. The state of art of SERS, including a theoretical background study, is briefly described. Finally, some recent development and applications of optical and analytical techniques for pesticides detection have been summarized; a particular study will be focused on SERS combined with microfluidic technology that has appeared as advanced tools for surface enhanced Raman spectroscopy (SERS). They have been demonstrated to be interesting for in situ and real-time detection of analytes at extremely low concentrations.