Polyhydric polymer-functionalized fluorescent probe with enhanced aqueous solubility and specific ion recognition: A test strips-based fluorimetric strategy for the rapid and visual detection of Fe 3+ ions.

A polyhydric polymer-functionalized probe with enhanced aqueous solubility was designed initially by coupling 1-pyrenecarboxyaldehyde (Pyr) onto poly(vinyl alcohol) (PVA) via the one-step condensation reaction. Polyhydric PVA polymer chains could facilitate the Pyr fluorophore with largely improved aqueous solubility and especially strong cyan fluorescence. Importantly, the fluorescence of the PVA-Pyr probes could thereby be quenched specifically by Fe3+ ions through the strong PVA-Fe3+ interaction triggering the polymeric probe aggregation. Furthermore, a test strips-based fluorimetric method was developed with the stable and uniform probe distribution by taking advantage of the unique film-forming ability and the depression capacity of "coffee-stain" effects of PVA matrix. The as-developed test strips could allow for the rapid and visual detections of Fe3+ ions simply by a dipping way, showing a linear concentration range of 5.00-300μM, with the detection limit of 0.73μM. Moreover, the proposed method was applied to the evaluation of Fe3+ ions in natural water samples, showing the analysis performances better or comparable to those of current detection techniques. This test strips-based fluorimetric strategy promises the extensive applications for the rapid on-site monitoring of Fe3+ ions in environmental water and the outdoor finding of the potential iron mines.