Gold-coated electrospun PVA nanofibers as SERS substrate for detection of pesticides

Owing to its ability to detect Raman signals from trace amount of Raman active samples, surface enhanced Raman scattering (SERS) substrate has emerged as an interesting field of research for different areas of applications. Herein, we demonstrate a large area with good degree of reproducibility SERS substrate using PVA nanofibers. Gold (Au) coated electrospun PVA nanofibers has been used as SERS substrate in the present study. Using the designed SERS substrate, Raman signal from malachite green (MG) with concentration as low as 10 nM has been measured reliably by the Raman spectrometer. The relative standard deviation (RSD) for signature peaks of this Raman active sample at 420 cm−1, 1188 cm−1, 1378 cm−1 and 1618 cm-1 were found to be 6.01%, 7.38%, 5.71% and 6.50% respectively. The usability of the designed SERS substrate for detection of three commonly used pesticides namely deltamethrin, quinalphos and thiacloprid has been successfully demonstrated. It has been observed that for concentration well below the maximum residue limit as set in the Global Agricultural Information Network (GAIN) report from United States department of agriculture (USDA) foreign agricultural service, with the proposed SERS substrate one can easily estimate the concentration of the pesticide samples well below the permissible limit.