Dual-signal amplified cathodic electrochemiluminescence aptsensor based on a europium-porphyrin coordination polymer for the ultrasensitive detection of zearalenone in maize

The sensitive and fast detection of mycotoxins is of considerable significance in the prevention of mycotoxin contamination in cereals. This study reports the ultrasensitive detection of zearalenone (ZEN) in maize by a novel dual-signal amplified cathodic electrochemiluminescence (ECL) aptsensor. The Eu-prorphyrin coordination polymer (Eu-PCP) exhibited a good cathodic ECL signal at - 1.5 V, and consequently the undesirable effect of the oxidation of interfering substances was avoided, which improved the selectivity and stability of the sensor. In particular, gold nanoparticles (AuNPs) accelerated the electron transfer rate and effectively improved the ECL signal of the Eu-PCP. Furthermore, the carboxyl-functionalized graphitic carbon nitride (C-g-C3N4) acted as a new co-reactant promoter, prompting the co-reactant S2O82- to generate more SO4- center dot radicals, which further enabled Eu-PCP to generate higher ECL signal. Under optimal conditions, the proposed ECL aptsensor showed a large linear range of 0.001-200 mu g kg-1 with a detection limit of 9.75 x 10-5 mu g kg-1 (S/N = 3). Finally, the dual-signal amplified cathodic ECL platform was successfully utilized to determine trace amount of ZEN, and its early detection is beneficial to avoid spoilage of maize.