Molecularly imprinted ultrathin graphitic carbon nitride nanosheets–Based electrochemiluminescence sensing probe for sensitive detection of perfluorooctanoic acid

Driven by the urgent demand for the determination of low level perfluorooctanoic acid (PFOA) present in environment, a novel electrochemiluminescence (ECL) sensor has been first developed for the detection of PFOA using the molecularly imprinted polypyrrole modified two-dimensional ultrathin g-C 3 N 4 (utg-C 3 N 4 ) nanosheets as a cathodic ECL emitter with S 2 O 8 2− as coreactant. The prepared molecularly imprinted polymer (MIP) functionalized utg-C 3 N 4 nanosheets (MIP@utg-C 3 N 4 ) exhibit a stable and significantly amplified ECL signal. It is found that the targets of PFOA could be efficiently oxidized by the electro-generated strong oxidants of SO 4 − (from the reduction of coreactant S 2 O 8 2− ), thus leading to a low yield of the excited utg-C 3 N 4 (g-C 3 N 4 *) and finally a decrease in ECL signal. Based on this, a highly sensitive and selective MIP@utg-C 3 N 4 -based signal-off ECL sensor is developed for sensing PFOA. Such a newly designed ECL sensor exhibits highly linear over the PFOA concentration in two ranges, from 0.02 to 40.0 ng mL −1 and 50.0–400.0 ng mL −1 . The detection limit (S/N = 3) is estimated to be 0.01 ng mL −1 (i.e. 0.01 ppb), comparable to the results obtained by using well-established liquid chromatography-tandem mass spectrometry (LC-MS/MS). Toward practical applications, this low-cost and sensitive assay was successfully applied to measure PFOA in real water samples, showing fine applicability for the detection of PFOA in real samples.