PMC

Correlation between the plasma polysulfide level and that of a biological fluid. Each polysulfide level was measured by EMSP. (a) tear polysulfide, (b) saliva polysulfide, (c) polysulfide in nasal discharge, and (d) seminal polysulfide.

Adsorption tests via UV–Vis. a Evolution of polysulfide with glucose in DOL/DME electrolyte solution; b UV–Vis spectrum of Li₂S₆ with glucose in DOL/DME electrolyte solution after a specific time; c comparison of LiPS adsorption between CMC and glucose. d, e Illustrating the evolution of polysulfide in the presence of high concentrate lithium polysulfide; f Raman spectra of suspensions and g FTIR spectra of washed solid residues.

Mechanisms of dihydroxybenzene-catalyzed polysulfide production. (A–C) Oxygen dependency of H₂S oxidation to polysulfides (SSP4 fluorescence) by 1,4-dihydroxybenzene (DB, A), benzoquinone (BQ, B) and pyrogallol (PG, C). Buffer containing 100 μM DB, BQ or PG in 3-mL glass vials was bubbled with 100% nitrogen (N₂), 21% oxygen (21% O₂) or 100% oxygen (100% O₂) for 20 min. H₂S (300 μM) was then added for 10 min, after which 200-μL aliquots were placed into 96-well plates and SSP4 added. With DB, polysulfide production increased between 0 and 21% O₂ but was decreased by 100% O₂. Effects of O₂ on polysulfide production by BQ were minimal, whereas polysulfide production by PG increased with increasing O₂. Mean + SE, n = 4 wells per treatment. (D) Effects of superoxide dismutase (SOD) on polysulfide production (SSP4 fluorescence) produced by 100 μM 1,4-dihydroxybenxene (DB) or pyrogallol (PG) oxidation of 300 μM H₂S in 21% O₂. SOD, DB and PG were added to wells 10 min prior to H₂S. SSP4 was added 10 min later and samples counted; results show responses at 130 min. SOD at 0.1 μM did not oxidize H₂S to polysulfides in buffer, whereas it increased polysulfide production by DB and decreased polysulfide production by PG; 1 μM SOD increased polysulfide production from H₂S in buffer and decreased polysulfide production by both DB and PG. Mean + SE, n = 4 wells; *, p < 0.05, ***, p < 0.001 compared to like treatment without enzymes. (E) Effects of ROS and free radical scavengers, tempol, trolox or DMPO (all 1 mM) on polysulfide production (SSP4 fluorescence) from 300 μM H₂S alone or H₂S plus 100 μM 1,4-dihydroxybenzene (DB) or 100 μM pyrogallol (PG). Scavengers and DB or PG were added to wells and allowed to react for 10 min before H₂S; SSP4 was added 10 min later. Both tempol and trolox increased polysulfide production when added to H₂S but decreased production when H₂S was added to either DB or PG; DMPO was ineffective in all conditions. The effect of tempol on polysulfide production from H₂S and H₂S plus DB was greater than that of trolox but less than H₂S plus PG. Mean + SE n = 4 wells per treatment; *, p < 0.05; ***, p < 0.001, significantly different from like control; ###, p < 0.001, significant difference between tempol and trolox.

a Left: H-cell setup for polysulfide crossover determination on single-AEM (FAA-3-PK-130) and CEM (Nafion 117); Right: redox flow battery setup for polysulfide crossover determination on the dual-membrane structure. b Cumulative crossover of the permeate solution in single-AEM, single-CEM and dual-membrane setup against permeation time, inset shows the dual-membrane polysulfide crossover measured at the air side. c Calculated polysulfide flux across single-AEM, single-CEM and dual-membrane structure. d EIS of CEM and AEM. e The polysulfide flux versus membrane conductivity. The error bars show the UV-Vis measurement error, conductivity measurement error and fitting errors.