Spin coated Ag NPs SERS substrate: trace detection study of methylene blue and melamine

In this study, silver nanoparticles (Ag NPs) are grown on glass substrate using simple low-cost spin coating method followed by chemical reduction. UV–Vis absorption spectra and scanning electron microscope images are used to examine the grown Ag nanoparticles. Effect of variation of revolution per minute (rpm) on the growth of Ag NPs and SERS activity of methylene blue (MB) is investigated. Ag NPs grown at 1000 rpm is found to be optimized SERS substrate giving enhancement factor of the order of 10 8 , facilitating detection of nano-molar MB and melamine with concentration well below the allowed limit in milk. Relative standard deviation values obtained for spot to spot (5.43%) and substrate to substrate (5.65%) reproducibility indicate good sensitivity and excellent reproducibility of the obtained SERS substrate. The present work provides simple and cost-effective method to fabricate Ag NPs SERS substrate for the trace detection of MB a water pollutant and melamine a milk adulterant.