Simultaneous Determination of Acetaminophen and Caffeine Based on Graphene Oxide/Cerium Hexacyanoferrate Modified Glassy Carbon Electrode

Graphene oxide was coated on glassy carbon electrode and cerium hexacyanoferrate was then electrodeposited on the modified electrode. Scanning electron microscope was used to characterize the modified electrode. The electrochemical behaviors of acetaminophen and caffeine on the modified electrode were investigated by cyclic voltammetry and differential pulse voltammetry. The experimental results showed that the electrochemical respond of acetaminophen and caffeine at the modified electrode was significantly improved in acetate buffer solutions (pH 5.0). The concentration of acetaminophen and caffeine showed good linear relationships with the oxidation peak current in the range of 1.0 x 10(-7) - 6.0 x 10(-5) mol/L and 1.0 x 10(-6) - 1.3 x 10(-4) mol/L, with correlation coefficients of R = 0.990 and 0.992, respectively. The limits of detection for acetaminophen and caffeine were 5.0 x 10(-8) mol/L and 5.2 x 10(-7) mol/L (S/N = 3), respectively. The developed method was used to the determination of spiked urine samples with recoveries of 96.1% - 105.4%.