A reaction based turn-on type fluorogenic and chromogenic probe for the detection of trace amount of nitrite in water

A turn-on fluorescent probe for the detection of nitrite ion in water is developed based on diazotization reaction of the amino group of the probe in an acidic solution (pH 1). The probe responds selectively to nitrite ion over various other anions with a turn-on type fluorogenic change from colorless to orange by the formation of rhodamine B via an analyte triggered fragmentation process. The fluorescence titration is complete within 1 h with 1 equivalent of nitrite ion. The probe is highly efficient, cost-effective and shows a detection limit of 4.6 ppb.