SELECTIVE KINETIC SPECTROPHOTOMETRIC DETERMINATION OF NITRITE IN FOOD AND WATER

A highly selective and sensitive method for the kinetic spectrophothometric determination of sub-microgram amounts of nitrite has been development based on its reaction with Nile blue 2B in acidic medium. The reaction is monitored spectrophotometrically at 595 nm at a fixed time of 4.5 min. The change in absorbance at 595 nm is related to the concentration of nitrite in the range 0.005 - 1.100 mu g.ml(-1) The detection limit is 0.001 mu g.ml(-1). The relation standard deviation is 1% for 0.020 mu g.ml(-1) of nitrite for ten replicate measurements. Most common anions and cations do not interfere. The procedure was applied to the determination of trace amounts of nitrite in sausage and water.