Solid state electrochemical of the erbium hexacyanoferrate-modified carbon ceramic electrode and its electrocatalytic oxidation of L-cysteine

A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF samples to the surface of CCEs derived from sol-gel technique was proposed. The resulting modified electrodes exhibit well-defined redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s(-1) in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry. Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about 400 mV for L-cysteine oxidation. The calibration plot for L-cysteine determination was linear at 5.0 x 10(-6)-1.3 x 10(-4) M with a linear regression equation of I(A) = 0.558 + 0.148c (mu M) (R-2 = 0.9989, n = 20), and the detection limit was 2 x 10(-6) M (S/N=3). At last, the ErHCF-modified CCEs were used for amperometric detection of L-cysteine in real samples.