A “signal on/off” biomimetic electrochemiluminescence sensor using titanium carbide nanodots as co-reaction accelerator for ultra-sensitive detection of ciprofloxacin

It is of great significance to explore an efficient and sensitive method for the detection of ciprofloxacin (CIP) for the protection of human health and ecological environment. In this study, a novel molecularly imprinted electrochemiluminescence sensor (MIECLS) was constructed using amino-functional titanium carbide nanodots (TNDs) as co-reactant accelerator in the cathodic electrochemiluminescence system. With K 2 S 2 O 8 as co-reactant, the obvious cathode luminescence signal of carbon nitride nanosheets (CNNS) can be observed under the synergistic effect of TNDs. TNDs not only advanced the conductivity of CNNS, and the presence of amino group accelerated the reduction of the co-reactant S 2 O 8 2− , which generated a rich ECL reaction intermediate SO 4 − • near CNNS, thus greatly enhancing the ECL signal of CNNS. In addition, the proposed MIECLS have good anti-interference, high sensitivity and selectivity by electropolymerization of o-phenylenediamine as functional monomer to form molecularly imprinted polymer (MIP) with specific recognition sites on electrode surface. The MIECLS was applied for determination of CIP, and its ECL intensity was linearly quenched with the increasing concentration of CIP from 5 × 10 −9 to 5 × 10 −6 mol L −1 with a detection limit of 1.20 × 10 −9 mol L −1 ( S / N = 3). Futhermore, in the actual sample analysis, the detection results of MIECLS showed good consistency with those of HPLC, indicating that MIECLS has a broad application prospect in the rapid and sensitive analysis of CIP in food samples. The luminescence mechanism of CNNS and the process of detecting ciprofloxacin in actual sample. • A “Signal on/off” MIECLS with good stability was constructed for the detection of CIP in food. • TNDs with –NH 2 was introduced as co-reaction accelerator to enhance ECL signals of CNNS/S 2 O 8 2− system. • CNNS has unique and excellent luminescence stability as luminescent emitter. • MIP based on electropolymerized o-phenylenediamine ensured specific CIP detection.