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

• A highly sensitive ECL sensor for rapid detection of PFOA developed.
• As-prepared sensor fabricated by MIP modified utg-C3N4 nanosheets.
• Unique ECL properties of MIP modified utg-C3N4 nanosheets explored.
• The first smart integration of utg-C3N4 with MIP yielding a novel ECL sensing probe.
• The resulting sensor exhibiting fine applicability for detection of PFOA in real samples.

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-C3N4 (utg-C3N4) nanosheets as a cathodic ECL emitter with S2O82− as coreactant. The prepared molecularly imprinted polymer (MIP) functionalized utg-C3N4 nanosheets (MIP@utg-C3N4) 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 SO4− (from the reduction of coreactant S2O82−), thus leading to a low yield of the excited utg-C3N4 (g-C3N4*) and finally a decrease in ECL signal. Based on this, a highly sensitive and selective MIP@utg-C3N4-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.

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