Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XVII
Written by Emilia OCNARU, Melania ARSENE, Gelu VASILESCU, Mihaela BADEA DONI
For nitrite determination in cured meat, we have developed an original amperometric method based on a modified sensor surface using nonconductive polymers. The nonconductive films allow the target analyte to cross the sensor surface where an electrochemical reaction is taking place, albeit, restricting intereferences. Compared to a spectroscopic method, which requires a stringent pH control and the use of carcinogenic reagents, the amperometric method for nitrite determination is simple, rapid, and does not require dangerous reagents. The polymeric films were deposited onto the Pt and carbon paste electrodes, using cyclic voltammetry. The monomers used for nonconductive polymer film development were: 2,6-dihydroxynaphtalene (2,6-DHN), o-dianisidine (o-DIA) and 1,8-diaminonaphtalene (1,8-DAN). From all the permselective membrane that we have studied, the 2,6-DHN/Pt based sensor presents the sensibility and endurance required for developing the further studies for nitrite detection using a batch and a flow injection analyse system (FIA). Electrochemical tests have shown that 2,6-DHN/Pt is sensitive for sodium nitrite detection, it restricts potassium ferricyanide crossing, and acts as a barrier against ascorbic acid interference. Ascorbic acid is a major interferent in food products.The 2,6-DHN/Pt has a linear range (5-200μM), a correlation factor of 0.9994, and a low detection limit (2.5μM, S/N=3). Such a sensor has the ability to detect nitrite in various meat samples (e.g., hot-dogs, ham, italian salami, and canned beef).
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modified electrodes
