Adenine MoS ₂ decorated pencil graphite electrode for detection of indigo carmine

The rising global concern over the harmful effects of synthetic colours has prompted regulatory bodies to strictly monitor their use in food. Indigo carmine, a petroleum-based dye, has been extensively used in the food, beverage and cosmetic industries. Numerous methods, including electrochemical ones, detect indigo carmine’s presence in various substrates. Despite this, incorporating biopolymers with metal sulphides has never been explored for indigo carmine detection. This study focuses on an innovative electrochemical approach utilising the promising transition metal dichalcogenide, molybdenum disulphide and nucleobase adenine to detect indigo carmine. This cost-effective platform serves as a viable option for ensuring food safety and for environmental monitoring through differential pulse voltammetry. The electrode offers exceptional sensitivity and selectivity, combined with high reproducibility for indigo carmine reduction in the nanomolar range of 10 nM to 500 nM, with lower limit of detection 0.4 nM and limit of quantification of 1.4 nM. As for real- time monitoring, the sensor was also used in the detection of indigo carmine in aerated drink, tap water and wastewater. The scope of this work lies in integrating this sensor into a portable monitoring device for continuous assessment of food and environmental in an economically feasible way.