Ultra-trace level voltammetric sensor for MB in human plasma based on a carboxylic derivative of Calix[4]resorcinarene capped silver nanoparticles

Abstract

This work was initiated by synthesizing a carboxylic derivative of Calix[4]resorcinarene through a three step protocol confirmed by proton nuclear magnetic resonance (1H NMR) spectroscopy and Electrospray ionization mass spectroscopy (ESI-MS). As synthesized derivative, was used as reducing and capping material for the fabrication of small and stable silver nanoparticles (AgNPs) in aqueous medium under the combined influence of dilute alkali and heat at 90 °C. These nanoparticles were referred as KM20-AgNPs. Techniques used for characterization of AgNPs include UV–Visible (UV–Vis) spectroscopy, Fourier transform infra-red (FTIR) spectroscopy, atomic force microscopy (AFM), dynamic light scattering (DLS) and zeta potential analyzer (ZPA). The finally produced KM20-AgNPs were recognized as highly sensitive and extremely selective voltammetric sensor for low level detection of methylene blue drug in the linear working range of 1–30 nM with limit of detection (LOD) and limit of quantification (LOQ) as 0.16 nM and 0.53 nM respectively. The developed sensor was successfully used for sensing of MB in human blood plasma.