Summary

Since the green revolution, pesticides have been an integral part of agricultural food production. A growing concern is the impact on human health due to consumption hazardous pesticides residuals in agricultural produce. Strict government regulations are in place and pesticides categorized by the world health organization as highly hazardous are banned in Sri Lanka. Frequent quality checks for the existence of harmful pesticide residues in both local and imported agricultural produce remains critical for detecting pesticide over usage. However, such efforts need the backing of robust onsite detection methods. Current practices often relies on chromatography based mass spectrometry, which requires elaborate sample preparation and is relatively expensive. Therefore, less expensive, easy to operate portable device technology able to detect below maximum residue levels prescribed by international pesticide regulatory agencies that can measure libraries of known hazardous pesticides will be important.The main objectives of this project is to develop Raman spectroscopy based methods; firstly to detect trace levels of selected pesticides and secondly to detect them below the relevant maximum residual limits using a custom designed portable device, which may also require the development of a suitable colloidal substrate that will enable the enhancement of Raman signal.

Objectives

1) Obtain pure Raman signature spectra for moderately hazardous heavily used pesticides in Sri Lanka.
2) Develop Au/Ag colloidal surface enhance Raman spectroscopy substrates for enhanced detection of above selected moderately hazardous pesticides.
3) Based on Raman signature spectra, develop regression models to quantify trace levels of selected moderately hazardous pesticides (~1 ppm).
4) Construct field portable Raman spectrometer and software able to detect multiple selected pesticide residues in agricultural produce below the European recommended maximum residue levels stipulated as per European regulation (EC) No. 396/2005

Major Equipment Facilitated by Grant