Application of Tris (1,10-phenanthroline-5,6-dione) Zinc(II)hexafluorophosphate Complex Modified Carbon Paste Electrode for Electrocatalytic Determination of Penicillamine in Rheumatoid Patient Serum Samples

A novel Zn(II)-fluorophore complex, tris(1,10-phenanthroline-5,6-dione)zinc(II) hexafluorophosphate, has been synthesized and structurally characterized for modification of carbon paste electrode. Then the fabricated electrode was applied as a highly selective and sensitive sensor for determination of penicillinamine. Despite of featureless voltammetric response of this complex in the range of +0.4 to +1.0 V, it exhibits potent electrocatalytic activity toward D-PA oxidation at +0.8 V. Impedance Spectroscopy (EIS) was used for comparing the surface electron transfer resistance of the modified and bare electrode and demonstrate that modified electrode make the electron transfer easier. Under the optimum conditions (pH=4.0), the oxidation current of penicillinamine was linearly related to its concentration in the range of 0.1-95.0 μmol L-1 with a detection limit of 0.05 μmol L-1 at the signal to noise of 3. Satisfactory results were achieved for determination of penicillinamine in serum samples of patients with rheumatoid arthritis using standard addition method.