A ratiometric fluorescent probe for bisulphite anion, employing intramolecular charge transfer

Abstract

4-(1H-benzimidazol-2-yl)benzaldehyde (1) has been developed as a new ratiometric fluorescent probe for bisulphite, based on the modulation of intramolecular charge transfer (ICT). Upon mixing with bisulphite in aqueous ethanol, an aldehyde-bisulphite adduct was formed and the ICT of the probe was switched off, which resulted in a ratiometric fluorescence response with an enhancement of the ratios of emission intensities at 368 and 498 nm. The detection range of the probe for bisulphite is in the 2.0-200 µmol/L concentration range and the detection limit is 0.4 µmol/L. Probe 1 produces a ratiometric fluorescent response to bisulphite with a marked emission wavelength shift (130 nm) and displays high selectivity for bisulphite over other anions.

A near-infrared fluorescent probe for rapid, colorimetric and ratiometric detection of bisulfite in food, serum, and living cells

“…Consequently, ratiometric probes with NIR fluorescent changes are very attractive to sense and detect important molecules of interest. To date, several fluorescent probes for HSO 3 − /SO 3 2− have been developed based on different approaches such as complexation with amines [15], the selective deprotection of levulinate group [16][17][18][19], the selective reaction with aldehyde [20][21][22][23][24][25][26] and Michael-type additions [27][28][29][30][31][32][33][34][35], however, many of them are intensity-based, in which factors such as instrumental efficiency, the probe concentration, and environmental conditions can interfere with signal output. In addition, almost all of these probes showed emissions only in the visible region, and some of them need to use ultraviolet excitation, which limited their biological applications.…”

A highly sensitive fluorescent probe for the detection of bisulfite ion and its application in living cells

“…In recent years, some fluorescent probes for detecting bisulfite have been developed mainly based on nucleophilic addition, such as the addition of bisulfite to an aldehyde moiety, polarized C=N bond or C=C bond of the probe [17][18][19][20][21][22][23][24][25][26][27]. However, most of available fluorescent probes for SO3 2-…”

An effective ICT-based and ratiometric fluorescent probe for sensing sulfite

“…The formyl group acts as an acceptor while the benzimidazole moiety acts as an electron donor, to form push-pull system 16 and reduce ICT process on [52]. However, ZSO reacted with sulfite to produce the adduct in which electron-withdrawing group disappeared, and induce ICT process off (Scheme 3).…”