Electrochemical Determination of Folic Acid in Fruit Juices Samples Using Electroanalytical Sensor Amplified with CuO/SWCNTs and 1-Butyl-2,3-dimethylimidazolium Hexafluorophosphate

Folic acid is an important food additive found in most food products. This research study focused on making a powerful analytical device to determine the folic acid concentration in food products. An electrochemical amplified sensor based on paste electrode (PE) modified with CuO-CNTs and 1-butyl-2,3-dimethylimidazolium hexafluorophosphate (BDHFP) was fabricated and used to study the electro-oxidation of folic acid. Oxidation current of folic acid was improved about 2.8 times at PE/M/CuO-CNTs/BDHFP compared with that of the PE. In addition, an irreversible and pH dependent oxidation signal was detected for redox reaction of folic acid at surface of PE/M/CuO-CNTs/BDHFP. Active surface area of PE was increased from 0.11 cm2 to 0.18 cm2 after modification with CuO-CNTs and BDHFP. Differential pulse voltammetric (DPV) signals displayed a linear dynamic range 3.0 nM–250 µM with detection limit 0.8 nM for measurement of folic acid. To study the ability of the PE/M/CuO-CNTs/BDHFP to determine the folic acid in real samples, apple and orange juices were selected and recovery data between 99.29%-101.6% confirm high performance ability of PE/M/CuO-CNTs/BDHFP for determination of folic acid in real samples.