Fast Detection of Nitrite with A Test Paper Tape

A test paper tape on the determination of nitrite in food was designed, which is based on the diazotization of nitrite with sulfanilic acid under weakly acidic conditions then coupled with N-(1-Naphthyl)-ethylenediamine dihydrochloride in forming the colour-producing response. Then the reaction membrane turned to purple-red. The deeper purple-red film was obtained in an increased nitrite concentration-dependent manner. Experimental results showed that nitrite concentrations were proportional to a values of the L a b color system. A favorable linearity was presented in the range of 25 to 5000 mu g/mL. The correlation coefficient(r) was 0.984 and the whole testing time needed was about 1.5 min at room temperature.