Electrochemical Detection of Nitrite in Meat and Water Samples Using a Mesoporous Carbon Ceramic SiO_2/C Electrode Modified with In Situ Generated Manganese(II) Phthalocyani

摘要

Mesoporous carbon ceramic SiO_2/50 wt% C (S_(BET)=170 m~2 g~(-1)), where C is graphite, were prepared by the sol-gel method. The materials were characterized using N_2 sorption isotherms, scanning electron microscopy, and conductivity measurements. The matrix was used as support for the in situ immobilization of Mn(II) phthalocyanine (MnPc) on their surface. XPS was used to determine the Mn/Si atomic ratios of the MnPc-modified materials. Pressed disk electrodes were prepared with the MnPc-modified matrix, and tested as an electrochemical sensor for nitrite oxidation. The linear response range, sensitivity, detection limit and quantification limit were 0.79–15.74 μmolL~(-1), 17.31 μALμmol~(-1), 0.02 μmolL~(-1) and 0.79 μmolL~(-1), respectively, obtained using cyclic voltammetry. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation was 1.7% for 10 measurements of a solution of 12.63 μmolL~(-1) nitrite. The sensor employed to determine nitrite in sausage meat, river and lake water samples showed to be a promising tool for this purpose.