Sodium Dithionite Purity and Decomposition Products in Solid Samples Spanning 50 Years

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-SO3-) 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.

Going Beyond the Limits of the Biorenewable Platform: Sodium Dithionite-Promoted Stabilization of 5-Hydroxymethylfurfural

The lack of thermal and storage stability and occurrence of side reactions during the processing of 5-hydroxymethylfurfural (5-HMF) limits its potential as biorenewable platform molecule. The addition of small amounts of the readily available sodium dithionite has a remarkable effect on promoting the stability of 5-HMF and inhibiting side reactions, thus helping to circumvent such limitations. The addition of sodium dithionite led to improvements in thermal stability (120 °C, 4 h, neat; 100 % vs. 37 %), under distillation (yield: 85 % vs. 52 %), and in a wide range of reactions, including 5-HMF synthesis under biphasic conditions (yield: 98 % vs. 67 %; purity: 92 % vs. 83 %) and 5-HMF transformations, such as Knoevenagel condensation with Meldrum's acid (yield: 96 % vs. 74 %), Cannizaro reaction (yield: quantitative vs. 83 %), and condensation with primary diamines to give pyridinium salts (yield: 88 % vs. 60 %).