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SO 2 derivatives and viscosity are important intracellular indicators, which are closely associated with various physiological metabolisms in organisms. The unregulated contents of SO 2 derivatives and viscosity in vivo commonly related to some disorders. In this work, probe JFT was developed relying on FRET and TICT mechanisms for the simultaneous detection of SO 2 derivatives and viscosity. JFT can rapidly detect viscosity levels with continuously enhanced fluorescence signals at 582 nm basing on the increasing of viscosity. Moreover, JFT was also sensitive to the changes of SO 2 derivatives level with a low detection limit (61.5 nM), rapid responding time (with 16 min), excellent selectivity and anti-interference capacity. JFT could detect bisulfite in real water, wine and food samples with high accuracy and recovery rate. Cell imaging indicated that JFT could monitor the endogenous SO 2 derivatives and viscosity in mitochondria. Importantly, JFT could recognize the cancer cells basing on the cell imaging difference of JFT in AGS and GES-1 cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This work describes the analysis of formaldehyde using a 96-well microplate as multiple headspaces for the separation of sulfur dioxide gas generated from the sulfite remaining after its reaction with the formaldehyde in the sample. The quantitation of the gas is by colorimetric detection of an indicator paper placed over the microplate. The samples are aqueous extracts of various foods that are possibly adulterated with formaldehyde. A known excess amount of sulfite is added to the extract solution aliquoted in the well. The remaining sulfite is acidified with hydrochloric acid to generate sulfur dioxide gas which diffuses through the headspace above the solution to be absorbed at the moist strip of the indicator paper placed over the mouth of the wells. Anthocyanins extracted from the butterfly pea flower is used as the pH indicator giving a color change from the increase of hydrogen ions by hydrolysis of the absorbed sulfur dioxide gas. The exposed paper strip is scanned, and the digital images of the colored region analyzed using ImageJ software. The optimized method has a linear range of 200-1000 mg L -1 formaldehyde with limit of detection ((2.57*SD of intercept)/(slope of calibration line)) of the aqueous extract of 40 mg L -1 and coefficient of determination (r 2 ) > 0.9979. Samples of fresh produce, such as seafood, meat, and vegetables, and various processed food were analyzed for their possible formaldehyde content. The results obtained from the headspace paper-based colorimetric detection are not statistically different from the values obtained from the titration method by paired t-tests., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: The commercial preservation of table grapes largely depends on the application of sulfur dioxide (SO 2 ). However, little is known about whether SO 2 participates in sulfur metabolism to improve the postharvest quality of table grapes. In this study, the contents of sulfur-containing compounds, activities of enzymes, and expression of genes involved in sulfur metabolism in table grapes (Vitis vinifera cv. Thompson Seedless) were evaluated., Results: The results indicated that SO 2 treatment maintained the postharvest quality of table grapes. The sulfite content in rachises and berries, but not the sulfate content, increased in response to SO 2 treatment. SO 2 caused high activities of sulfite reductase, O-acetylserine (thiol)-lyase, and γ-glutamylcysteine synthetase, thereby increasing the contents of cysteine, hydrogen sulfide, and glutathione in the rachises and berries. The expression of VvSURTL, VvATPS1, VvATPS2, and VvAPR3 decreased in response to SO 2 treatment; however, the transcript levels of VvSiR1 and VvOASTL exhibited the opposite tendency., Conclusion: These findings indicated that the sulfite converted from SO 2 participated in sulfur metabolism and maintained the postharvest quality of table grapes by modulating the contents of metabolites, activities of enzymes, and expression of genes related to sulfur metabolism. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

Epilepsy is the fourth most common neurological disorder, and aberrantly elevated sulfur dioxide derivatives (SO 3 2- /HSO 3 - ) are thought to underlie the hippocampal neuronal apoptosis in epilepsy. We have designed and synthesized a mitochondria-targeted polydopamine nanoprobe for visualizing endogenous SO 3 2- /HSO 3 - by the nucleophilic addition reaction. The nanoprobe was used for imaging SO 2 derivatives both in the mitochondria of cultured cells and zebrafish, and successfully applied in the hippocampus of a rat model of epilepsy. The PDAD nanoprobe could be of great value for the elucidation of mechanisms of abnormal SO 3 2- /HSO 3 - involved in diseases such as epilepsy.

Based on the addition reaction of the sulfur dioxide derivative to the CC double bond, the probe HDI was designed and synthesized. The two-channel fluorescent probe HDI changed from orange to colorless and the fluorescence changed from red to blue when the bisulfite was detected. And the probe responds rapidly to bisulfite within 2 min, with high sensitivity and specificity. In addition, the probe can be used to detect the concentration of bisulfite with a low detection limit (80 nM). Cytological experiments have also demonstrated that probe HDI has low cytotoxicity and could be used for ratiometric detection of sulfur dioxide derivatives in living cells., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Ratiometric fluorescent probes have shown great potential for optical sensing and have been widely used for bioimaging. However, due to extremely stringent molecular design, most conventional organic ratiometric fluorescent probes can only achieve one single ratio. Currently, the detection of a target in living systems in a multiratiometric manner is prominently challenging. Therefore, it is of great significance to develop a method to construct the multiratiometric fluorescent probes for accurate quantitative detection of specific small molecules. To address this challenge, we developed a unique multiratiometric composite fluorescent probe. Herein, a new triple-ratiometric fluorescent composite nanoprobe CP@GQDs-OH based on OH-functionalized GQDs (GQDs-OH) and red emission ratiometric fluorescent molecular probe (CP) was prepared through π-π stacking. The novel nanoprobe showed high selectivity for SO 2 with three linear ratio changes. Significantly, CP@GQDs-OH was successfully applied for the detection of SO 2 in the living cells and zebrafishes by the unprecedented triple-ratiometric fashion.

While formaldehyde (HCHO) was likely generated in Earth's prebiotic atmosphere by ultraviolet light, electrical discharge, and/or volcano-created lightning, HCHO could not have accumulated in substantial amounts in prebiotic environments, including those needed for prebiotic processes that generate nucleosidic carbohydrates. HCHO at high concentrations in alkaline solutions self-reacts in the Cannizzaro reaction to give methanol and formate, neither having prebiotic value. Here, we explore the possibility that volcanic sulfur dioxide (SO 2 ) might have generated a reservoir for Hadean HCHO by a reversible reaction with HCHO to give hydroxymethanesulfonate (HMS). We show that salts of HMS are stable as solids at 90°C and do not react with themselves in solution, even at high (>8 M) concentrations. This makes them effective stores of HCHO, since the reverse reaction slowly delivers HCHO back into an environment where it can participate in prebiotically useful reactions. Specifically, we show that in alkaline borate solutions, HCHO derived from HMS allows formation of borate-stabilized carbohydrates as effectively as free HCHO, without losing material to Cannizzaro products. Further, we show that SO 2 can perform similar roles for glycolaldehyde and glyceraldehyde, two intrinsically unstable carbohydrates that are needed by various models as precursors for RNA building blocks. Zircons from the Hadean show that the Hadean mantle likely provided volcanic SO 2 at rates at least as great as the rates of atmospheric HCHO generation, making the formation of Hadean HMS essentially unavoidable. Thus, hydroxymethylsulfonate adducts of formaldehyde, glycolaldehyde, and glyceraldehyde, including the less soluble barium, strontium, and calcium salts, are likely candidates for prebiotically useful organic minerals on early Earth.

We report a novel fluorescent probe HBN-TCF for the detection of SO2 derivatives. This probe exhibited near-infrared fluorescence emission with an excitation wavelength of 620 nm. After reacting with SO32-, the emission channel at 664 nm decreased, while the new strong emission channel at 482 nm increased (λex = 400 nm), with a large emission distance (Δλ = 182 nm) observed. This probe exhibited the rapid and selective detection of SO2 derivatives compared with other sulfur-containing species and featured a low detection limit (82 nM). This colorimetric and ratiometric fluorescent probe showed high selectivity and sensitivity for detecting SO2 derivatives. The probe was also successfully exploited for the fluorescence imaging of intracellular and exogenous SO2 derivatives in BEL-7402 cells.

In this study, we developed a multi-signal mitochondria-targeted fluorescent probe (NIR-Cys) for simultaneous detection of Cys and its metabolite, SO2. In the design of the probe, the acrylate group and the C[double bond, length as m-dash]C of the coumarin ring were used as the recognizing moiety for Cys and SO2, respectively. The probe exhibited high sensitivity, excellent specificity, and fast response. NIR-Cys was found to precisely target and visualize Cys metabolism in mitochondria of living cells with a multi-fluorescence signal. This probe is expected to be a useful tool for understanding Cys metabolism.

A colorimetric fluorescent probe with fluorescence emission feature sensitive to SO 2 derivatives, i.e. bisulfite (HSO 3 - ) and sulfite (SO 3 2- ), was developed based on the HSO 3 - /SO 3 2- -mediated nucleophilic addition reaction of the probe that. This probe exhibited SO 3 2- sensing ability with detection limit down to 46 nM and desired selectivity over other reference anions and redox species. The preliminary fluorescence bioimaging experiments have validated the practicability of the as-prepared probe for SO 2 derivatives sensing in living cells.

Sulphiting agents are well-known food preservatives. The European legislation does not allow their addition in fresh meat preparations. Therefore this type of food products has often been verified. To high sulphite levels in food is a health safety risk, due to toxic effects that these compounds may exercise on humans. In this study the control activity as performed by an Italian accredited laboratory from 2013 to 2015, relating to determination of sulphites in meat products, is described. Six hundred and sixty-nine meat product samples were analysed. Both applied techniques, a screening method (malachite green test) and a confirmatory method (ion chromatography), were accredited. Forty-three samples resulted positive at screening test and nineteen of these samples showed high-sulphite concentrations, in the range 67.6-1437 mg kg -1 . The non-negligible percentage of positives (6.4%) and the high concentrations verified confirmed that the control of sulphuring treatment of fresh meat preparations is an important task for organisations in charge of food inspections and control.

A turn-on fluorescent probe Coumarin-SO2 based on a nucleophilic addition reaction was developed for the rapid detection of SO3(2-) in aqueous media. The probe Coumarin-SO2 displays excellent water solubility, fast response, highly sensitivity and highly selectivity over other biological related species. More importantly, living cell imaging experiments indicate the feasibility of using the probe for the detection of SO3(2-) in biological systems., (Copyright © 2015 John Wiley & Sons, Ltd.)

Sulfur dioxide (SO2) and its derivatives sulfite and bisulfite play important roles in biological systems. However, in vivo detection of sulfite/bisulfite remains challenging. In this study, we developed a dinuclear Ir(III) complex (Ir4) as a two-photon phosphorescent probe for sulfite and bisulfite. Ir4 selectively and rapidly responded, with high sensitivity, to sulfite/bisulfite over other bio-related ions and molecules. One-photon and two-photon microscopy images revealed that Ir4 preferentially targeted mitochondria and was capable of imaging biological sulfite/bisulfite levels in vitro and in vivo. In situ sulfite generation in Caenorhabditis elegans was visualized by two-photon excitation real-time imaging. Finally, Ir4 was employed to monitor sulfite distribution in rat brain and other tissues. This study is the first report of the direct visualization of SO2 derivatives in vivo. These results provide new insights into the biological importance of SO2., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

4-(Benzothiazol-2-yl)-3-hydroxybenzaldehyde, probe 1, has been developed as a ratiometric fluorescent probe for the sensitive and selective detection of sulfur dioxide with a fast response time (within seconds). This probe itself exhibited a yellow emission (λmaxem = 563 nm) with a 186 nm Stokes shift. Upon treatment with sulfite anions, this probe instantaneously displayed a blue emission (λmaxem = 467 nm) with a 133 nm Stokes shift. The large Stokes shifts and absorption spectral overlap of probe 1 both in the absence and in the presence of SO3(2-)/HSO3(-) allow the fluorescence detection under single wavelength excitation. Importantly, this ratiometric probe was successfully demonstrated for the imaging of intracellular sulfite anions in living cells.

Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH < 1 was treated by membrane extraction at 25 ℃. This operation is based on a hydrophobic Hollow Fiber Contactor, which separates the acidified red wine in the shell side and a diluted aqueous sodium hydroxide solution as receiving solution into the lumenside in countercurrent. Sulfite and bisulfite in the acidified red wine become molecular SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability., (© The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

A simple and effective anion ion chromatography (IC) method with anion exchange column and conductivity detector has been developed to determine free sulfites (SO3-2) in dried fruits processed with sulfur dioxide. No oxidation agent, such as hydrogen peroxide, is used to convert sulfites to sulfates for IC analysis. In addition, no stabilizing agent, such as formaldehyde, fructose or EDTA, is required during the sample extraction. This method uses aqueous 0.2 N NaOH as the solvent for standard preparation and sample extraction. The sulfites, either prepared from standard sodium sulfite powder or extracted from food samples, are presumed to be unbound SO3-2 in aqueous 0.2 N NaOH (pH > 13), because the bound sulfites in the sample matrix are released at pH > 10. In this study, sulfites in the standard solutions were stable at room temperature (i.e., 15-25 degrees C) for up to 12 days. The lowest standard of the linear calibration curve is set at 1.59 microg/mL SO3-2 (equivalent to 6.36 microg/g sample with no dilution) for analysis of processed dried fruits that would contain high levels (>1000 microg/g) of sulfites. As a consequence, this method typically requires significant dilution of the sample extract. Samples are prepared with a simple procedure of sample compositing, extraction with aqueous 0.2 N NaOH, centrifugation, dilution as needed, and filtration prior to IC. The sulfites in these sample extracts are stable at room temperature for up to 20 h. Using anion IC, the sulfites are eluted under isocratic conditions with 10 mM aqueous sodium carbonate solution as the mobile phase passing through an anion exchange column. The sulfites are easily separated, with an analysis run time of 18 min, regardless of the dried fruit matrix. Recoveries from samples spiked with sodium sulfites were demonstrated to be between 81 and 105% for five different fruit matrixes (apricot, golden grape, white peach, fig, and mango). Overall, this method is simple to perform and effective for the determination of high levels of sulfites in dried fruits.

Sulfur dioxide (SO(2)) is important in the winemaking process as it aids in preventing microbial growth and the oxidation of wine. These processes and others consume the SO(2) over time, resulting in wines with little SO(2) protection. Furthermore, SO(2) and sulfiting agents are known to be allergens to many individuals and for that reason their levels need to be monitored and regulated in final wine products. Many of the current techniques for monitoring SO(2) in wine require the SO(2) to be separated from the wine prior to analysis. This investigation demonstrates a technique capable of measuring free sulfite concentrations in low volume liquid samples in white wine. This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte. We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring.

The experiment of Longan fruit cv. Biew Kiew, untreated (control) and treated with SO2 treatment were stored under 2 +/- 2 and 7 +/- 2 degrees C for 0, 2, 4, 6 and 8 weeks were studied. The treatment of fresh longan fruit with SO2 fumigation combined with the suitable storage condition improved the overall longan fruit quality, especially on inner and outer peel tissue and aril color than no SO2 treatment. Treatment stabilizes peel color with no subsequent loss of color during storage (fruit color were bright-yellowish color). When the fruit showed during SO2 treatment, increasing of storage duration and temperatures, the dark color of inner and outer peel of longan fruit was appeared, this was correlated with the increasing of PPO activity. The activity of PPO enzyme in control fruit (no SO2 treatment) gradually lower than SO2 treatments. Fruit exposed to cool storage temperature (2 degrees C) exhibited a lower PPO enzymatic activity compared to those kept in high storage temperature (7 degrees C). Moreover, PPO enzymatic activity significantly increased over the storage durations The additional SO2 treatment no subsequent loss of weight of longan fruit during storage. However, the sulphite residues could detect immediately after SO2 treatment in all part of longan fruit, especially on aril tissue. The SEM evaluation found that the surface cracking was also impair the physiological function of the cuticle and increasing water permeability, which may cause water soaking at the inner side of the peel. The injured cell would accelerate the oxidation of phenolic substances and the oxidative products resulted in dark color of inner and outer peel.

Background: Ischemia-reperfusion (I/R) injury is an important clinical problem. This article investigated the role of sulfur dioxide (SO2) in the regulation of cardiac function and in the pathogenesis of cardiac I/R injury in isolated rat heart., Methods: Rat hearts isolated on a Langendorff apparatus were divided into control, I/R, I/R+SO2, and I/R+hydroxamate groups. Hydroxamate is an inhibitor of SO2 synthetase. I/R treatment was ischemia for 2 hr in hypothermic solution (4 degrees C), then reperfusion/rewarming (37 degrees C) for 60 min. Cardiac function was monitored by MacLab analog to a digital converter. Determination of sulfite content involved reverse-phase high performance liquid chromatography with fluorescence detection. Myoglobin content of coronary perfusate was determined at 410 nm. Myocardial malondialdehyde (MDA) was determined by thiobarbituric acid method, and conjugated diene (CD) was extracted by chloroform. 5,50-Dithiobis-2-nitrobenzoic acid was used to determine glutathione (GSH)., Results: The results showed that I/R treatment obviously increased myocardial sulfite content, and sulfite content of myocardium was negatively correlated with the recovery rate of left-ventricle developed pressure and positively correlated with the leakage of myoglobin. In postreperfusion, myocardial function recovery was decreased by SO2. During reperfusion, myocardium-released enzymes, MDA and CD level were increased but myocardial GSH content was depressed with the treatment of SO2 donor. Incubation of myocardial tissue with SO2 significantly increased MDA and CD generation., Conclusions: Endogenous SO2 might be involved in the pathogenesis of myocardial I/R injury, and its mechanism might be associated with an increase in lipid peroxide level and a decrease in GSH generation.

To study whether sulfur dioxide (SO(2)) can enter into the different organs of mice exposed to SO(2), the sulfite contents in brains, hearts, and lungs from male mice were determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD). After reduction and precolumn derivation of tissue homogenates of brains, hearts, and lungs from mice, the mixture was centrifuged, and 5 microl of the resulting supernatant was directly injected into HPLC; the mobile phase consisted of methanol-phosphoric acid (12:88, v/v), and for the fluorescence detection lambdaEX 392 nm and lambdaEM--479 nm were used. The standard curve was linear in the range from 0.126 microg/ml to 126 microg/ml; the minimal detectable concentration was 0.04 microg/ml (S/N = 3), the average methodological recoveries were from 97% to 101%, and the within-day and between-day precisions were less than 9%. These results showed that sulfite contents in all organs tested from mice in the SO(2)-exposed groups were significantly increased (p < .05) in a dose-dependent manner (r > .92) compared with the control groups. These results indicated SO(2) could transform into sulfite in vivo after inhalation, and could distribute into lung and other organs such as brain and heart. These results offered a support for the viewpoint that SO(2) is a systemic toxic agent.

A program is under way at the University of Tulsa to develop a viable process concept whereby a microbial process can impact on the problem of flue gas desulfurization and NOx removal. We have previously reported studies of SO2 reduction by Desulfovibrio desulfuricans and NOx reduction by Thiobacillus denitrificans. One potential process concept is the simultaneous combined removal of SO2 and NOx from cooled flue gas by contact with cultures of sulfate-reducing bacteria (SO2----H2S) and T. denitrificans (H2S----SO4(-2) as cultures-in-series or in coculture in a single contacting stage. Each of these contacting schemes has been investigated.

Results for determination of sulfur dioxide in grapes were compared by 3 methods: the modified Monier-Williams method, acid distillation/ion exclusion chromatography with electrochemical detection (AD/IEC-EC), and alkali extraction/ion exclusion chromatography with electrochemical detection (AE/IEC-EC). An unusual positive response was observed during the later stage of the Monier-Williams distillation of both control grapes and sulfited grapes. Development of volatile acidic compounds in parallel with this Monier-Williams response and darkening of sample was also observed by collection in an alkali trap and analysis using anion exclusion chromatography and photodiode array detection. No parallel increase in sulfite was observed by the more selective AD/IEC-EC method, which clearly demonstrated that the response observed during the later stage of the Monier-Williams method is a false positive, probably due to caramelization reaction products. Monier-Williams results for grapes containing ca 10 ppm sulfite were in reasonably good agreement with those by either the AD/IEC-EC or AE/IEC-EC methods, presumably because the false positive response in the Monier-Williams analysis compensated for the somewhat incomplete recovery of sulfite. The AE/IEC-EC method is recommended because it is rapid, sensitive, straightforward, and free from interference. Accurate results by Monier-Williams analysis could be obtained by limiting distillation to 60 min and correcting for recovery.

A method based upon a combination of a modified Monier-Williams procedure and an HPLC separation and quantitation of sulphite, has been developed. Its efficiency has been tested, in comparison with the Monier-Williams method, for the SO2 recovery in various foods. Desorption of SO2 from different matrices is obtained by distillation in strongly acid solution. Gaseous SO2, collected and oxidized to sulphate with hydrogen peroxide, is neutralized with sodium hydroxide. The neutralized solutions are diluted and injected by an autosampling injector into an HPLC apparatus consisting of a strong anion exchange column, eluted with a potassium hydrogen phthalate solution (0.15 g/l, pH 5.7) at a 3 ml/min flow rate and detected at 280 nm by an UV spectrophotometer. The combined method shows a good detection limit as well as high chromatographic resolution, avoiding potential interference of other volatile compounds. It is also time-saving and utilized basic laboratory equipment.