Conjugated polyelectrolyte-stabilized silver nanoparticles coupled with pyrene derivative for ultrasensitive fluorescent detection of iodide.

A new sensing system is developed for selective and ultrasensitive detection of iodide based on the inner filter effect (IFE) between conjugated polyelectrolyte-stabilized silver nanoparticles (P1-AgNPs) and 4-oxo-4-(pyren-1-ylmethoxy) butanoic acid (probe 1). P1-AgNPs are designed to be capable of functioning as a composite light-absorber. Meanwhile, probe 1 is selected as an ideal fluorophore because its emission spectrum can perfectly overlap with the absorption band of P1-AgNPs. The intense fluorescence of probe 1 quenched by P1-AgNPs can be efficiently recovered after adding H2O2 and I(-) via the oxidation-etching and regeneration of P1-AgNPs. Under the optimum conditions, this facile IFE-based approach allows the sensitive and selective determination of I(-) in tap water, iodized salt and urine with the detection limit as low as 0.3 nM (S/N=3). Interestingly, the regenerated AgNPs is in smaller size and well-dispersed perhaps due to the particular role of P1 as a polymer localizer containing pyridinyl and sulfonate groups.
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