A new sensing platform based on a ternary nanocomposite of graphitic carbon nitride-silver sulfide-nickel molybdate...

In this study, we have shown how to prepare a ternary nanocomposite (Ag₂S-NiMoO₄-g-C₃N₄) consisting of graphitic carbon nitride (g-C₃N₄) nanosheets, silver sulfide (Ag₂S) nanocrystals, and nickel molybdate (NiMoO₄) nanorods and its sensing ability to detect quercetin, a flavonoid found in many fruits and vegetables. An Ag₂S-NiMoO₄-g-C₃N₄ nanocomposite-modified screen-printed electrode (SPE) exhibited remarkable sensing performance in a quercetin (Que) concentration range of 0.005 μM-20 μM with a low detection limit of 2.7 nM. Moreover, we have aimed at improving the selectivity and sensitivity of a sensor for detecting Que by optimizing the composition of Ag₂S-NiMoO₄-g-C₃N₄, the film thickness, and the electrolyte pH. The sensor's selectivity for Que was tested in the presence of potential interferents such as ascorbic acid, citric acid, fructose, glucose, lactose, maltose, mannose, sucrose, and tyrosine. The performance of the sensor was tested on a variety of food samples, including green apple, green tea, honey, and red onion skin.