Synthesis of hydrotalcite-supported CdTe semiconductor nanocrystals for electrochemical detection of ciprofloxacin

Abstract

In this work, CdTe quantum dots (QDs) were controllably grown onto the surface of layered double hydroxide (LDH) aiming to develop a sensitive and selective method for the electrochemical detection of ciprofloxacin (CPX). Emission and absorption spectroscopy results as well as high-resolution transmission electron microscopy (HRTEM) images evidenced the formation of LDH/QD hybrid material. Unmodified carbon paste electrodes (CPE) as well as CPE chemically modified (MCPE) with native LDH and with the LDH/QD hybrid were prepared for CPX detection, revealing that MCPE-LDH/QD had the highest sensitivity for the detection of ciprofloxacin. Optimum detection conditions included a modifier dosage of 20% in MCPE, Britton-Robinson (BR) buffer (pH 6.0) as analytical medium, 300 s accumulation time and a scanning rate of 20 mV s-1. Linear current versus concentration curve was observed from 2.5 × 10-8-1.2 × 10-5 mol L-1 (coefficient of determination (R2) = 0.995), with sensitivity (limit of detection (LOD) = 4.2 × 10-8 mol L-1; limit of quantification (LOQ) = 1.3 × 10-7 mol L-1), precision (relative standard deviation (RSD) = 3.0%), accuracy (94.0%) and satisfactory selectivity in the presence of Zn2+, Fe2+, Cu2+, citric acid and ascorbic acid. Tests of CPX determination in commercial 500 mg ciprofloxacin tablets evidenced the applicability of the method.