Electrocatalytic Determination of Cysteamine in the Presence of Folic Acid Using a Modified Carbon Nanotube Paste Electrode

Electrocatalytic oxidation of cysteamine at a carbon paste electrode modified with benzoylferrocene has been studied. The modified electrode showed excellent electrocatalytic activity toward cysteamine oxidation in phosphate buffer solution (PBS) (pH 7.0) with an overpotential of about 225 mV lower than that of the bare electrode. Under the optimized experimental conditions, the proposed electrochemical cysteamine sensor exhibited a linear calibration plot ranged from 7.0x10(-8) to 2.5X10(-4) M with a detection limit of 5.0x10(-8) M. Also, Square wave voltammetry (SWV) was used for simultaneous determination of cysteamine and folic acid at the modified electrode. Finally, the proposed method was applied to the determination of cysteamine and folic acid in urine.