Label-free detection of Thiram pesticide on flexible SERS-active substrate

Thiram (tetramethyl thiuram disulfide) is a fungicide and is used for crop protection. It has several health-related issues when we consume this for a long period. Food and drug administration (FDA) warns higher than 30 μM (7 ppm) limit. Hence, the monitoring of the Thiram pesticide in foods and vegetables is of utmost importance. Conventional techniques such as GC–MS, HPLC and LC-MS available for quantification of pesticides are very costly, time-consuming and require sophisticated laboratory with highly skilled manpower. This work aims to design and develop an efficient label-free SERS (Surface Enhanced Raman Spectroscopy) active substrate which can detect a very low-level concentration of pesticides with low cost and simple process. SERS is a surface-sensitive technique that provides the enhanced form of Raman signals. Gold nanoparticles are used for SERS-active substrate preparation which has been synthesized by the chemical reduction method. Thiram pesticide with concentration as low as 1 nM is detected with the SERS substrate developed in this work. This makes rapid and on-site detection of pesticides feasible in future.