Virtually specific UV-molecular probe for nitrite sensing

Abstract

A highly sensitive and selective UV-molecular probe has been developed for detection of low concentrations of nitrite in aqueous solution based on monotonous increase in absorbance of rhodamine 6G at 385 nm. Addition of nitrite also results in a bathochromic shift in UV absorption maximum of rhodamine 6G from 355 to 385 nm. The optimal conditions for parameters like concentration of H2SO4 and rhodamine 6G, response time and stability is reported. Under optimised conditions, the developed UV-probe enables the determination of 0 to 0.5 mgL(-1) of nitrite. On the other hand, the addition of other anions like I-, SCN-, ClO4-, [HgI4](2-) and [Zn(SCN)(4)](2-) shows a bathochromic shift from 525 (the visible range absorption maximum) to 575 nm with no perceptible absorption at 385 nm. This enabled a virtually specific UV-molecular probe for rapid, precise and reliable monitoring of traces of nitrite in environmental samples and food materials with no interference from other anionic or cationic species. Studies with pyronine G also exhibit similar spectral characteristics on addition of nitrite