Copper phthalocyanine conjugated graphitic carbon nitride nanosheets as an efficient electrocatalyst for simultaneous detection of natural antioxidants

•A novel CuPTc/g-C3N4Ns nanocomposite was prepared using sonochemical approach.•This is the first attempt to prepare CuPTc/g-C3N4Ns nanocomposite and electron transfer mediator for simultaneous electrochemical determination of antioxidants.•The presented CuPTc/g-C3N4Ns/ITO has showed wide linear range with lowest detection limit compared with published reports.•The CuPTc/g-C3N4Ns/ITO has successfully used for the detection of antioxidants in commercial fruit drinks and the obtained results were compared with HPLC technique. Foodborne antioxidants including ascorbic acid (AA), caffeic acid (CA) and gallic acid (GA) are beneficial nutritional sources and thereby the analysis of the critical antioxidant is demanding for public health. Here, a sonochemical method was used to obtain hybrid copper-phthalocyanine conjugated graphitic carbon nitrides nanosheets (CuPTc/g-C3N4Ns) in which carboxylic acids and hydroxyl groups were added on the basal plane of g-C3N4. As prepared materials were characterized by various physicochemical and electroanalytical techniques, the CuPTc/g-C3N4Ns nanocomposite showed an excellent electrocatalytic activity towards antioxidants quantifications by using Indium Tin Oxide (ITO) coated glass plate. Under optimized experimental conditions, sensitive electrochemical detection of antioxidants was achieved on the CuPTc/g-C3N4Ns nanocomposite-modified ITO which resulted in wide linear concentration range of 0.05-500 µM (AA), 0.05-501 nM (CA) and 10-445 nM (GA) and the limit of detection (LOD) of 0.006 µM, 0.008 nM and 0.5 nM respectively. Furthermore, the fabricated sensor was successfully used for the antioxidants determinations in different commercial fruit juice, alcoholic beverages and tea samples with good recovery results demonstrating a hybrid phthalocyanine conjugated 2D carbon nanocomposite as an efficient electrocatalyst of desirable practical importance. [Display omitted]