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 ۵, ۱۰% modifier in electrode, potentialscanning rate of ۲۰ mVs-۱ and puls height of ۵۰ 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 ۱-۱۰ and ۱۰-۸۰ 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.

Modified carbon paste, Cu(II)-Salen, Voltammetric determination, Cysteine