A non-enzymatic photoelectrochemical sensor based on g-C3N4@CNT heterojunction for sensitive detection of antioxidant gallic acid in food.

[Display omitted] • A low cost and simple method for the detection of gallic acid in food. • The g-C 3 N 4 @CNT has good chemical stability and non-toxicity. • This is a covalently bonded "signal-on" high-sensitivity non-enzyme PEC sensor. • The constructed PEC sensor has an ultra-low LOD and a wide linear range. • This is first PEC sensor based on g-C 3 N 4 @CNT heterojunction to detect gallic acid. Gallic acid (GA) is found in a wide range of natural plants and is relevant to the health of human beings. Here, a photoelectrochemical sensing platform based on g-C 3 N 4 @CNT heterojunction has been prepared for the highly sensitive and selective detection of GA. Under the light of xenon lamp, the photocurrent of g-C 3 N 4 @CNT is 7 times higher than that of g-C 3 N 4. And the sensor generates 4 times more photocurrent in the presence of GA than without GA. This sensor has a wide linear range from 10 nM to 10 μM with a limit of detection as low as 2 nM. Also, the abundant amino groups of g-C 3 N 4 provide excellent selectivity for the sensor. Furthermore, the sensor can be used for the analysis of GA in black tea samples, which provides a novel and rapid method for the detection of GA in food samples. [ABSTRACT FROM AUTHOR]