Application of cetyltrimethylammonium bromide - graphene modified electrode for sensitive determination of caffeine

An electrochemical sensor based on a cationic surfactant cetyltrimethylammonium bromide (CTAB) - dispersed graphene (Gr) system for sensitive detection of caffeine is presented. The electrochemical behavior of caffeine on the modified glassy carbon electrode was investigated by cyclic voltammetry and differential pulse voltammetry. The results showed that the modified electrode exhibited good electrocatalytic activity to the oxidation of caffeine. Under the optimized experimental conditions, caffeine was detected in the concentration range from 0.3 to 100 mu mol L-1 with a detection limit of 91 nmol L-1 at a signal-to-noise ratio = 3. The biosensor exhibited some advantages over other electrochemical sensors, such as long-term stability, satisfactory recovery (98.1%-102.3%), and good reproducibility (RSD = 5.1%). The practical application of the developed method was verified in soft-drink sample analysis.