A carbon-paste electrode spiked with ferrocenedicarboxylic acid (FDCMCPE) was constructed by incorporation of ferrocenedicarboxylic acid in a graphite powder–paraffin oil matrix. It has been shown by direct current cyclic voltammetry and double-step chronoamperometry that this electrode can catalyze the oxidation of ampicillin (AMPC) in aqueous buffered solution. It has been found that under the optimum condition (pH 10.0) in cyclic voltammetry, the oxidation of AMPC occurred at a potential of about 480mV on the surface of the modified carbon-paste electrode. The kinetic parameters such as electrontransfer coefficient, a, and rate constant for the chemical reaction between AMPC and redox sites in FDCMCPE were also determined using electrochemical approaches. Under the optimized conditions, the electrocatalytic oxidation peak current of AMPC showed two linear dynamic ranges with a detection limit of 0.67 mmol L1 AMPC. The linear calibration was in the range of 2.34–30 mmolL1 and 40–700 mmol L1 AMPC using the differential pulse voltammetric method. Finally, this method was also examined as a selective, simple, and precise electrochemical sensor for the determination of AMPC in real samples such as drugs and urine.
کلید واژگان :Ampicillin, carbon-paste electrode, electrocatalysis, ferrocenedicarboxylic acid, voltammetry
ارزش ریالی : 600000 ریال
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