Two New Manganese(II) Complexes Bulk-Modified Carbon Paste Electrodes: Preparation and Electrocatalytic Activities

Two new manganese complexes of {Mn[(2-py)CNOH](2)Cl-2} (1) and {Mn[(2-py)CNOH](2)(OAc)(2)} (2) were synthesized and their structures were characterized by X-ray crystallography, IR spectroscopy and elemental analysis. Two complexes were used as bulk modifier to fabricate two carbon paste electrodes (Mn-CPE: 1-CPE and 2-CPE). The electrochemical behaviors of two modified electrodes were characterized by cyclic voltammetry. They have similar electrochemical behaviors and good electrocatalytic activities toward the reduction of hydrogen peroxide and nitrite. The results are reproducible with a lower detection limit than earlier reports. There exist a good linear relationship between peak current with the concentration in the range of 0.10-1.20 mu M and a detection limit of 0.08 mu M for hydrogen peroxide, and in the range of 0.02-0.10 mu M and a detection limit of 0.01 mu M for nitrite. Also Mn-CPE exhibits remarkable long term stability, simple preparation and inexpensive material, which is important for practical application on electrochemistry sensors.