Electrochemical determination of vitamin C in the presence of NADH using a CdO nanoparticle/ionic liquid modified carbon paste electrode as a sensor

A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanoparticle and 1-methyl-3-butylimidazolium bromide was used for the voltammetric analysis of vitamin C in the presence of nicotin amide adenine dinucleotide. The highly sensitive sensor shows excellent enhancement and electrocatalytic activity towards vitamin C. The variation of pH shows the number of protons is equal to number of electrons for vitamin C electrooxidation. The electrooxidation peak current of vitamin C and nicotin amide adenine dinucleotide increased linearly with their concentration in the ranges of 0.07-480 μmol L- 1 vitamin C and 0.5-700 μmol L- 1 nicotin amide adenine dinucleotide. The limits of detection for vitamin C and nicotin amide adenine dinucleotide were 0.03 μmol L- 1 and 0.1 μmol L- 1, respectively. Simultaneous determination of vitamin C and nicotin amide adenine dinucleotide was investigated by using the square wave voltammetry technique. The proposed sensor showed good stability, sensitivity, selectivity, and reproducibility and can be used for some important food sample analyses.