Flexible carbon fiber cloth supports decorated with cerium metal- organic frameworks and multi-walled carbon nanotubes for simultaneous on-site detection of Cd2+ and Pb2+ in food and water samples

The widespread heavy metal pollution endangers human health; hence, accurate on-site detection and quantification of heavy metal content in the surroundings is a vital step in reversing the harmful effect. Herein, an electrochemical sensor based on flexible cerium metal-organic framework@multi-walled carbon nanotubes/carbon cloth (CeMOF@MWCNTs/CC) was constructed for simultaneous on-site detection of Cd2+ and Pb2+ in food and water samples. The rich carboxyl groups of MWCNTs provided abundant sites for the adsorption of Cd2+ and Pb2+, and the mutual conversion of Ce3+ and Ce4+ in CeMOF facilitated the reduction and reoxidation of metal ions. The prepared electrode showed excellent performance in the simultaneous measurement of Cd2+ and Pb2+, with detection limits of 2.2 ppb and 0.64 ppb, respectively. More importantly, the sensing platform has been successfully used to detect simultaneously Cd2+ and Pb2+ in grain and water samples, and the detection results were consistent with the standard methods, showing great potential in environmental monitoring and food safety.