Determination of sulfite in food and beverages using a reliable ratiometric AIE probe

Abstract

Sulfite is an extensively used additive in foods and beverages, while its abuse could bring about health hazards, making the fast, reliable and economic assay of sulfite very important. Herein, an AIE-active fluorescent probe featured with intramolecular charge transfer (ICT) characteristics is exploited to detect sulfite in a ratiometric manner within 4 minutes. Thanks to the AIE attribute, an approximately 6-fold fluorescence enhancement is shown. Moreover, the probe enjoys higher selectivity to SO₃²⁻ over other competitive anionic species including HSO₃⁻, HS⁻ and SO₄²⁻. The sensing mechanism has been clearly confirmed by ¹H NMR and HRMS. Benefiting from the fast ratiometric response, high selectivity, superior anti-interference capability, and wide linear response range, the presented probe is capable of evaluating sulfite levels in sugar, liquor, peach brandy, red wine, and beer, with high accuracy and small deviation. It is noteworthy that the high reliability of the probe has been fully validated by iodometry.