Determination of L-cysteine at iron tetrasulfonated phthalocyanine decorated multiwalled carbon nanotubes film modified electrode

A sensitive amperometric sensing platform has been developed for the determination of L-Cysteine (L-Cys) at iron tetrasulfonated phthalocyanine (FeTsPc) decorated multiwalled carbon nanotubes (MWCNT) composite film modified electrode. Surface morphological studies revealed uniform decoration of the FeTsPc at the surface of MWCNT. MWCNT-FeTsPc composite modified GCE has been prepared which exhibited prominently enhanced electrocatalytic performance to the oxidation of L-Cys with two oxidation peaks that are associated with FeTsPc mediated electrocatalysis. The overpotential of the oxidation peaks were greatly reduced to - 0.1 V and + 0.22 V, while the peak currents were significantly improved in comparison with control electrodes. An amperometric sensor was fabricated which exhibited excellent electroanalytical parameters for the determination of L-Cys including wide linear range (i0 μM to 0.2 mM) and very low detection limit (1 μM). Practical feasibility of the sensor has been assessed in human urine samples. Moreover, the sensor exhibited excellent stability, repeatability and reproducibility results.