A salicylaldehyde based dual chemosensor for zinc and arsenate ion detection: Biological application

Abstract

We report here 2-((2-morpholinoethylimino)methyl)-4-bromophenol (Hmmbp) as a dual chemosensor for the detection of Zn2+ and H2AsO4− ions in 10 mM HEPES buffer in water: methanol (9: 1, v/v) (pH = 7.4). It has been synthesized by the condensation between 5-bromo-2-hydroxybenzaldehyde and 2-morpholinoethanamine and characterized by different methods. Its fluorescence intensity at 458 nm increases by 32-fold in the presence of one eqv. of Zn2+ (λex:378 nm). Fluorescence enhancement occurs via PET and CHEF mechanism. Other cations cannot induce any considerable change in fluorescence properties of the probe. LOD value for Zn2+ has been determined to be 4.41 × 10−7 M. On the other hand, fluorescence intensity of Hmmbp enhances at 503 nm with one eqv. of H2AsO4− ion (λex:414 nm). In case of anion sensing, restriction of CN isomerization due to hydrogen bonding and ICT mechanism are responsible for the changes of fluorescence of Hmmbp. Detection limit for H2AsO4− has been found to be 3.22 × 10−7 M. The chemosensor is selective for arsenate ion over several common anions. It forms 1:1 complex with both Zn2+ and H2AsO4−.The probe has been utilized to image both the species using C6 rat brain glioma cells.