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

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+ (lambda(ex):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 x 10(-7) M. On the other hand, fluorescence intensity of Hmmbp enhances at 503 nm with one eqv. of H2AsO4- ion (lambda(ex):414 nm). In case of anion sensing, restriction of C-N 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 x 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.

Automated summary

Hmmbp is a dual chemosensor capable of detecting Zn2+ and H2AsO4- ions with significantly enhanced fluorescence intensity. The chemosensor exhibits selectivity towards arsenate ions over other common anions. Additionally, it forms 1:1 complexes with both Zn2+ and H2AsO4- ions.