Bimetallic Ag–Au nanoparticles as pH dependent dual sensing probe for Mn(II) ion and ciprofloxacin

Abstract

A facile and eco-friendly method for the synthesis of bimetallic nanoparticles of two coinage metals such as silver and gold ((Ag–Au)mixNP) are detailed in this paper. β-cyclodextrin mediated microwave method was used for the synthesis of bimetallic nanoparticles in aqueous medium. Under the optimal conditions, the addition of Mn(II) ion and ciprofloxacin (CIP) changed the colour and surface plasmon resonance of the (Ag–Au)mixNP. The pH dependent changes associated with the introduction of CIP and Mn(II) ion in (Ag–Au)mixNP were studied using various characterization techniques such as UV–vis., FT-IR, XRD, zeta potential, dynamic light scattering, transmission electron microscopy, EDAX and electrochemical techniques. The host-guest interaction and the corresponding morphological changes of bimetallic nanoparticles induced the aggregation of nanoparticles resulting in a visual colour change of the brick red colour of (Ag–Au)mixNP. The electrochemical behaviour of the (Ag–Au)mixNP/AuE electrode in presence of Mn(II) ion and CIP is a highly sensitive detection method. The detection limits of Mn (II) ion by optical and electrochemical methods were 18.40 and 8.42 nM, respectively. In the case of CIP, these limits were found to be 10.26 and 7.24 nM, respectively. The successful monitoring of Mn(II) ion and CIP were possible in real samples with optical and electrochemical methods.