Electrocatalytic oxidation and amperometric determination of BHA at graphite–wax composite electrode with silver hexacyanoferrate as electrocatalyst

A graphite–wax composite electrode chemically modified with silver hexacyanoferrate (AgHCF) as a redox mediator was fabricated. Cyclic voltammetry was used to study the redox property of the AgHCF modified graphite–wax composite electrode. Various experimental parameters influencing the electrochemical behavior of the modified electrode were optimized by varying the background electrolytes, scan rates and pH. The electrochemical rugosity of the modified electrode at various scan rates was calculated from the anodic wave of the cyclic voltammogram. The feasibility of using the AgHCF modified electrode to measure butylated hydroxyanisole (BHA) was investigated. The modified electrode showed an excellent electrocatalytic activity towards the oxidation of BHA in 0.1 M KNO3 at pH 6. The analytical utility of the electrode as an amperometric sensor for the determination of BHA in a flow system was evaluated by carrying out hydrodynamic and chronoamperometric studies. Under optimized conditions amperograms were recorded and it was found that the oxidation current increased linearly with successive addition of BHA in the concentration range of 7.4 × 10−6–8.3 × 10−4 M. The limit of detection was found to be 3.7 × 10−6 M. For 10 successive determination of BHA at a concentration of 1.79 × 10−4 M, the relative standard deviation (R.S.D.) was 1.3%. The electrode showed a good electrochemical response in terms of sensitivity, stability and reproducibility. The proposed sensor was applied to the determination of BHA in spiked samples of dehydrated potato flakes.