A reversible chemosensor for nitrite based on the fluorescence quenching of a carbazole derivative

The carbazole derivative, with an amino group in 9-position (9-methylacryloylamino carbazole (MAC), has been utilized to prepare a fluorescent sensor and used for the determination of NO(2)(-) based on the reaction between nitrite (NO(2)(-)) and excess I(-) to form I(3)(-), which can quench the fluorescence of carbazole derivative. MAC, as a fluorescent carrier, has a terminal double bond and is covalently immobilized on a quartz glass plate surface by photo-polymerization to prevent the leakage of the dye. The sensor shows sufficient repeatability, selectivity, operational lifetime of 8 weeks, and a fast response of less then 30s. NO(2)(-) can be determined in the range between 1.0x10(-6) and 1.0x10(-4)moll(-1) with a detection limit of 8.0x10(-7)moll(-1) at pH of 2.0. The quenching mechanism is discussed. Most commonly coexisting ions do not interfer with the NO(2)(-) assay.