Progress and challenges in the detection of residual pesticides using nanotechnology based colorimetric techniques

Pesticides are generally used to control and prevent agricultural pests. Excessive and sporadic use of pesticides poses a serious threat to human and livestock life. Therefore, to safeguard the people's health simple and sensible approaches for the determination of residual pesticides in food items are desperately required. The nanotechnology-based colorimetric approaches provide the options for detection of residual pesticides with high precision and speed. Localized surface plasmon resonance (LSPR) is one of the most prominent features of metal nanoparticles which provides unique optoelectronic characteristics in the visible region of the electromagnetic spectrum. Metal nanoparticles especially gold and silver have very high extinction coefficients, therefore a well-suited electrochemical interaction between target analytes and nanoparticles surfaces cause aggregation, which leads to a colorimetric response. Modification and functionalization of nanoparticles with other ligands enhances the sensitivity and selectivity of colorimetric assays. But still, there are major challenges which affect the efficacy of these techniques for onsite pesticides monitoring which need to be addressed. Therefore, a comprehensive review of progress and challenges in the application of nanotechnology-based colorimetric techniques for detection of residual pesticides is presented here. The mechanism behind the development of these analytical techniques is also discussed, briefly. In conclusion, potential future trends and prospects of colorimetric techniques are addressed. (C) 2020 Elsevier B.V. All rights reserved.