An immobilization-free and homogeneous electrochemiluminescence assay for detection of environmental pollutant graphene oxide in water

As a new type of environmental pollutant, the toxicity of graphene oxide (GO) has been worldwide concerned, however, studies on detection of such pollutant is rarely studied up to date. In this work, an immobilization-free homogeneous electrochemiluminescence (ECL) method for effective detection of GO was developed based on the quenched ECL signal of luminol induced by GO. As an important luminophor, luminol possessed super ECL performance in alkaline buffer solution at bare glassy carbon electrode; while after GO was added, the inhibited ECL signal was obtained due to the dynamic quenching process between luminol emitter and GO quencher. More interestingly, the inhibited ECL signal of the luminol was depended on the concentration of the added GO. Under optimal conditions, a good linear relationship between the inhibited ECL signal of luminol versus the logarithm of the concentration of GO was obtained in the range of 0.08 ~ 800 μg mL−1 with a detection limit of 0.03 μg mL−1 (S/N = 3). Moreover, the method provided recoveries of 103 ~ 107.5% for river water and 108 ~ 110.6% for chemical wastewater when applied to spiked samples of real environmental water.