Bisphenol-A sensor platform based on AgNPs and SERS application

In the present study, three sensitive surface-enhanced Raman spectroscopy (SERS) analytical methods for determining bisphenol-A (BPA) in various drinks and baby food samples were developed. The results obtained were studied comparatively using silver nanoparticles. For this purpose, our approach is based on i) uniform and tunable assembly of Beta vulgaris L. root-stabilised AgNPs 1, ii) the use of ascorbic acid, and iii) hydroxylamine hydrochloride as a reducing agent for AgNPs 2 and AgNPs 3, respectively. Herein, we demonstrate a bottom-up approach that relies on the direct growth of silver nanostructures. The procedures for substrate preparation were systematically optimised. For this reason, the silicon wafer surface was used as the substrate. The silver nanostructure-coated silicon wafer substrates provide high SERS signals, and reproducibility is significantly improved. A scanning electron microscope was used to characterise the morphologies of the resulting substrates, and the chemical composition of the nanostructures was determined by energy-dispersive X-ray spectroscopy attached to the SEM. Also, the nanostructures were confirmed by the characterisations of zeta potential, UV - vis spectra, and Fourier transform infrared spectroscopy (FT-IR). Based on statistical analyses, the relative standard deviations for substrate-to-substrate were both 3.2%. Under optimum conditions, the proposed methods exhibit a good linear relationship in the concentration ranges of 10-2-10-8 mol L-1 for BPA. The SERS substrates were successfully used to detect BPA in some drinks and baby food samples.