Nitrogen oxide air pollutants interfere with the measurement of nitric oxide using 2,3-diaminonaphthalene: reduction of background interference.

Nitrite, a stable metabolite of nitric oxide (NO), is measured fluorometrically as an indicator of NO production using 2,3-diaminonaphthalene. In cultured cells, it has been believed that a longer period of incubation improves the detection sensitivity because of the accumulation of nitrite formed from NO in culture media. However, here we show that nitrite formed from nitrogen oxide air pollutants accumulates continuously in culture media during the incubation and interferes with the measurement of NO as nitrite. Thus, a proper period of incubation is important to allow maximum nitrite signals from NO with minimum background nitrite from the air.