Paper based low-cost flexible SERS sensor for food adulterant detection

A simple in-situ one-step silver mirror reaction (SMR) was utilized for the growth of silver nanostructures (AgNS) on filter paper (P1,0.01; P2,0.1; and P3,0.2M AgNO3) for SERS substrates. Concentration dependent growth of AgNS, with the evolution of multifaceted structures have been achieved. Further, SERS substrates were employed to detect Methylene blue (MB) and Crystal violet (CV) and fM sensitivity was achieved. Water spiked with melamine and urea were detected at limit of detection (LOD) of 0.1 mM; 0.2 mM concentrations, and for milk samples detection level was found to be 1.69 mM; 0.48mM respectively. Reproducibility of SERS sensor was achieved, with RSD values of <8% for water spiked samples, and for whole milk it was <12.28%. The achieved sensitivity and LODs for water and whole milk samples were found to be either superior or comparable with reported literature. Moreover, the stability of P3 SERS substrate was examined after 4 months for MB, CV, whole milk spiked with melamine and urea, and found to be ¿94% efficiency. Thus, the fabricated paper based SERS substrate, offers high sensitivity, selectivity, stability, and cost-effective approach, for on-site detection of chemical contaminant in water and milk samples.