A new chemically modified electrode is constructed based on iron(III) doped zeolite modified carbon paste electrode (Fe3＋Y/ZMCPE). The new sensor could be used for the simultaneous determination of the biologically important compounds dopamine (DA) and tyrosine (Tyr). The measurements are carried out using differential pulse voltammetric (DPV) method. The prepared modified electrode shows voltammetric responses of high sensitivity, selectivity and stability for DA and Tyr under optimal conditions, which makes it a suitable sensor for simultaneous trace detection of DA and Tyr in solution. Application of the DPV method demonstrates that in the Briton Robinson buffer solutions (pH＝5) containing 50 μmol/L Tyr, there is a linear relationship between the oxidation peaks and the concentrations of DA over the range of 0.1—200 μmol/L, with a detection limit of 0.05 μmol/L (S/N＝3). For Tyr a linear correlation between oxidation peak current and concentration of Tyr over the range of 0.5—200 μmol/L (containing 50 μmol/L DA), with a detection limit of 0.08 μmol/L is obtained. The analytical performances of this sensor are evaluated for the detection of DA and Tyr in human serum and a medicine.
