Electrocatalytic oxidation of thiosulfate at 2,7-bis(ferrocenylethyl)-fluoren-9-one-modified carbon paste electrode (2,7-BFEFMCPE): Application to the catalytic determination of thiosulfate in real sample

Electrocatalytic oxidation of thiosulfate at the 2,7-BFEFMCPE occurs at a potential about 460 mV less positive than that unmodified carbon paste electrode. The diffusion coefficient (=5.6 × 10−5 cm2 s−1), the kinetic parameters such as electron transfer coefficient, (=0.5) and kh (=1.21 × 10−3 cm s−1) of thiosulfate oxidation at the surface of, 2,7-BFEFMCPE were determined. The electrocatalytic oxidation peak current of thiosulfate showed two linear dynamic ranges (0.0006–0.009 mmol/L and 0.009–0.900 mmol/L) and a detection limit of 0.00015 mmol/L. This method was also examined as a new electrochemical sensor for the determination of thiosulfate in real sample.