A novel colorimetric HSO4− sensor in aqueous media

Abstract

A novel and sensitive anion receptor 3, bearing Schiff base structure, nitrophenyl azobenzol and carboxyl groups, was developed and characterized as a single chemosensor for the recognition of HSO4− anion. The different responses of UV–vis spectra and color changes of 3 could be applied to the recognition for HSO4− over other anions such as F−, CI−, Br−, I−, AcO−, H2PO4− and CIO4− by the naked eye. Furthermore, the anion binding interaction of receptor-anion was also studied using UV–vis and 1H NMR titration which revealed that 3 displayed a remarkable binding ability for the HSO4− with an association constant Ka=6.59×104M−1. And the detection limitation of HSO4− with the receptor 3 was 2.0×10−6molL−1 in aqueous solution. Most importantly, the qualitative detection of HSO4− using receptor 3 was attempted with test kit which was made from receptor 3.