Individual and Simultaneous Electrochemical Determination of Vanillin and Caffeine Using Nafion/Ethylenediamine Grafted Multi-walled Carbon Nanotubes Modified Boron-doped Diamond Electrode

A boron-doped diamond electrode (BDDE) modified with Nafion-ethylenediamine grafted multiwalled carbon nanotubes (EDA-MWCNTs) composite was fabricated for the simultaneous quantification of Vanillin (VAN) and Caffeine (CAF). Firstly, the MWNTs are functionalized with acyl chloride groups, which further react with EDA to form amine-functionalized MWCNTs. The experimental findings showed that the modified BDDE had high activity for the electrochemical oxidation of both compounds. In 0.10 M H2SO4, the linear range for the detection of binary mixtures of VAN and CAF with square wave voltammetry (SWV) was 0.4-40 μM and the reached detection limits were 0.15 μM and 0.18 μM (LOD =3SD/m), respectively. The modified BDDE was successfully utilized to establish VAN and CAF in different samples with recoveries range of 94%−102% and 95%−100%, respectively.