β-Cyclodextrin capped gold nanoparticles and nanodiamond assembled on a porous gold mini-chip as a disposable electrochemical sensor for bisphenol A

Abstract

ABSTRACT Herein, a disposable electrochemical sensor was constructed from a gold DVD (GDVD) mini-chip modified with pores, β-cyclodextrin capped gold nanoparticles (AuNPs@β-CD), and nanodiamond (ND). For this purpose, the LSV method was employed to deposit a silver film on the surface of the mini-chip. Then, the silver was replaced with gold using galvanic replacement, after which etching of silver by nitric acid and ammonia was accomplished to obtain a porous GDVD mini-chip (PGDVD). Next, AuNPs@β-CD and thereafter, an aqueous ND dispersion were successively drop-cast on the PGDVD. Finally, the as-prepared mini-chip was exposed to air to obtain the PGDVD@AuNps@β-CD@ND mini-chip. The electrochemical oxidation behaviour of BPA showed an irreversible oxidative wave with decreased oxidation overpotential and increased current response for BPA. The calibration curve was linear over the concentration range of 5 × 10−5 M to 1 × 10−3 M of BPA. According to the 3sb/m and 10sb/m criteria, the limits of detection (LOD) and quantitation (LOQ) of the method were obtained to be 1 × 10−5 M and 5 × 10−5 M, respectively. Also, the reproducibility of the method (RSD%) was obtained to be 4%. The proposed sensor was employed for the analysis of spiked tap water and apple juice samples.