Voltammetric determination of cysteine at a carbon paste electrode modified with Cu(II)-salen complex

The electrochemical behavior of a modified carbon paste electrode (MCPE) with N,N′ethylenbis(salicylideneiminato)copper(II) complex ([Cu(II)-Salen]) was investigated as a newsensor for cystein. The Britton-Robinson buffer with pH 5, 10% modifier in electrode, potentialscanning rate of 20 mVs-1 and puls height of 50 mV were used as the optimum condition for thedetermination of cysteine using carbon paste electrode modified with Cu(II)-Salen complex. Underthese optimum conditions, the resulting electrode demonstrated linear response with cysteineconcentration in the range of 1-10 and 10-80 μM. The effects of potential interfering species werestudied and it was found that only thiocyanate ion interfered in cysteine determination and theproposed procedure was free from most other interferences.