Electrochemiluminescence Sensor Based on N-Doped Carbon Quantum Dots for Determination of Ceftazidime in Real Samples

Abstract

In this work, we report an electrochemiluminescence (ECL) sensor based on nitrogen doped carbon quantum dots (N-CQDs), which has been synthesized by a solvothermal method. The N-CQDs were characterized using various techniques such as high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), UV–vis absorption and photoluminescence spectroscopy, FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The potential sweep range (−0.5 to −2.2 V) shows a stable and strong ECL signal. Interestingly, the ECL intensity only decreased by less than 20% after storing at 4 °C for 10 months. The applicability of the N-CQD sensor in electroanalytical chemistry was identified by the linear ECL on–off response for ceftazidime in a concentration range from 1 × 10−7 to 5 × 10−4 mol l–1 and a detection limit of 2.3 × 10−8 mol l–1. The results suggest that the proposed ECL sensor is robustly applicable for analysis of ceftazidime in real samples such as human serum, bovine milk and commercial milk powder.