Fast detection of sodium dithionite in sugar using a xanthylium-based fluorescent probe.

Dithionite remained in the foodstuff may pose a great threat to the health of consumers. Three xanthylium-based probes were synthesized and their responses to dithionite were explored. Probe SH-1 could respond to dithionite selectively in PBS buffer (15% DMSO, 10 mM, pH = 7.4). Upon the addition of dithionite, the fluorescent emission of SH-1 at 684 nm dropped quickly (within 10 s) and the fluorescence decline was proportional to the concentration of dithionite (0–7.0 μM). The limit of detection was determined to be 0.139 μM. Then, the sensing mechanism was tentatively presented and the structure of resulted adduct (SH-1-SO 3 − ) which was the reaction product of SH-1 and dithionite via a Micheal addition reaction followed by an oxidation reaction was verified. Moreover, white granulated sugar was subjected to the standard spike experiments and the results demonstrated a great potential of SH-1 for the quantitative monitoring of dithionite in foodstuffs. [Display omitted] • A xanthylium-based fluorescent probe for fast dithionite detection (within 10 s) was developed. • SH-1 could discriminate dithionite and bisulfite effectively with a LOD of 0.139 μM. • SH-1 exhibited a great potential for dithionite detection in sugar and other foodstuffs. [ABSTRACT FROM AUTHOR]