A Highly Selective Turn-on and Reversible Fluorescent Chemosensor for Al3+ Detection Based on Novel Salicylidene Schiff Base-Terminated PEG in Pure Aqueous Solution

Abstract

The development of highly selective and sensitive chemosensors for Al3+ detection in pure aqueous solution is still a significant challenge. In this work, a novel water-soluble polymer PEGBAB based on salicylidene Schiff base has been designed and synthesized as a turn-on fluorescent chemosensor for the detection of Al3+ in 100% aqueous solution. PEGBAB exhibited high sensitivity and selectivity to Al3+ over other competitive metal ions with the detection limit as low as 4.05 × 10−9 M. PEGBAB displayed high selectivity to Al3+ in the pH range of 5–10. The fluorescence response of PEGBAB to Al3+ was reversible in the presence of ethylenediaminetetraacetic acid (EDTA). Based on the fluorescence response, an INHIBIT logic gate was constructed with Al3+ and EDTA as two inputs. Moreover, test strips based on PEGBAB were fabricated facilely for convenient on-site detection of Al3+.

Water-soluble optical sensors: keys to detect aluminium in biological environment

“…In 2019, Wang and coworkers reported three polymer-based highly selective and sensitive ‘turn-on’ Al 3+ sensors by incorporating conventional Schiff base fluorophores onto the non-toxic, biocompatible, water-soluble polyethylene glycol (PEG) matrix. 68–70 The one-step esterification of benzoylhydrazine Schiff base derivative with carboxylated PEG yielded 17 with a 1 : 1 stoichiometry and an excited state intramolecular proton transfer (ESIPT)-based sensing mechanism upon complexation. The chelation of Al 3+ stops the CN isomerization and restricts the ESIPT process, making the complex rigid and thereby enhancing fluorescent intensity to a greater extent (Fig.…”

A new highly selective “off–on” typical chemosensor of Al3+, 1-((Z)-((E)-(3,5-dichloro-2-hydroxybenzylidene)hydrazono)methyl) naphthalene-2-ol, an experimental and in silico study

“…SI3 †) showed clearly the appearance of imine moiety by a typical C]N vibration at 1612 cm À1 (strong, sharp). The appearance of the aromatic group of naphthalene and substituted benzaldehyde was assigned by the vibration of sp 2 C-H at 3074 cm À1 (medium, sharp) and C]C aryl at 1467 cm À1 (medium, sharp). However, the sign of -OH moiety was barely apparent, which might be due to intramolecular hydrogen bonding with the nitrogen of imine.…”

“…Aluminum is the most abundant metal element in the earth's crust 1,2 and is widely utilized to support human daily needs such as for kitchen ware, electrical apparatus, in the pharmaceutical industry, and also food for packaging materials. 3,4 As a consequence, humans can be exposed easily to Al 3+ ions for long periods, resulting in slow accumulation in various human organs through food, drugs, and water.…”

A naphthalene-based azo armed molecular framework for selective sensing of Al3+

“…The presence of excess Na 2 EDTA disturbs the effective complexation of Al 3+ with HL in every cycle and finally arrests the luminescence. 69…”