Role of reactive manganese and oxygen species in the KMnO4/Na2SO3 process for purification of algal-rich water and membrane fouling alleviation.

Ultrafiltration (UF) is a highly efficient technique for algal-rich water purification, but it is heavily contaminated due to the complex water characteristics. To solve this problem, potassium permanganate (KMnO4) oxidation enhanced with sodium sulfite (Na2SO3) was proposed as a pretreatment means. The results showed that the end-normalized flux was elevated from 0.10 to 0.91, and the reversible fouling resistance was reduced by 99.95%. The membrane fouling mechanism also changed obviously, without the generation of cake filtration. Regarding the properties of algal-rich water, the zeta potential was decreased from -29.50 to -5.87 mV after KMnO4/Na2SO3 pretreatment, suggesting that the electrostatic repulsion was significantly reduced. Meanwhile, the fluorescent components in algal-rich water were significantly eliminated, and the removal of dissolved organic carbon was increased to 67.46%. In the KMnO4/Na2SO3 process, reactive manganese species (i.e., Mn(V), Mn(III) and MnO2) and reactive oxygen species (i.e., SO4•- and •OH) played major roles in purifying algal-rich water. Specifically, SO4•-, •OH, Mn(V) and Mn(III) could effectively oxidize algal pollutants. Simultaneously, the in-situ adsorption and coagulation of MnO2 could accelerate the formation of flocs by decreasing the electrostatic repulsion between cells, and protect the algal cells from being excessive oxidized. Overall, the KMnO4/Na2SO3 process showed significant potential for membrane fouling alleviation in purifying algal-rich water.

Untargeted metabolomics combined with vitro antioxidant to comprehensively evaluate the effect of sodium sulfite immersion on the holistic quality of mung bean sprouts.

Mung bean sprouts are widely consumed as a seasonal fresh vegetable, renowned for their affordability and richness in antioxidants and bioactive compounds. This study employed ultra-high-performance liquid chromatogram-Q-Exactive HF mass spectrometry (UHPLC-QE-MS) and multivariate statistical analysis to comprehensively evaluate the chemical profile of mung bean sprouts following sulfite immersion. The findings revealed a significant alteration in the overall chemical composition of mung bean sprouts following sodium sulfite immersion. Eleven components, including four sulfur-containing compounds, were identified as characteristic markers distinguishing between non-immersed and sodium sulfite-immersed mung bean sprouts. Esterification and addition reactions were inferred to occur during sodium sulfite immersion, leading to the transformation of flavonoid and saponin sulfates. Commercial samples analysis indicated that sulfur-containing compounds were detectable in 9 of 11 commercial mung bean sprouts. Meanwhile, when sodium sulfite concentration exceeded 3.00 mg/mL and immersion time exceeded 360 min, the contents of total polyphenol and flavonoid were significantly reduced and the antioxidant activity was adversely influenced.

Tuning Structural Characteristics of Corn Stover Through Ammonium and Sodium Sulfite (ASS) Pretreatment for Enhanced Enzymatic Hydrolysis.

The ammonia fiber expansion (AFEX) pretreatment of lignocellulosic biomass offers a significant advantage in terms of obtaining high glucan conversion, with the added benefit of ammonia being fully recyclable. However, despite the high efficiency of AFEX in pretreating lignocellulose, relatively high enzyme loading is still required for effective cellulose conversions. In this study, we have updated the AFEX pretreatment method; ammonia and sodium sulfite (ASS) can be used to produce a more digestible substrate. The results demonstrate that ASS-pretreated corn stover (CS) yields a higher fermentable sugar yield compared with AFEX pretreatment, even at lower enzyme loadings. Specifically, at an enzyme loading of 12 mg protein/g glucan, ASS-CS achieved 88.8% glucose and 80.6% xylose yield. Characterization analysis reveals that lignin underwent sulfonation during ASS pretreatment. This modification results in a more negative zeta potential for ASS-CS, indicating a reduction in nonproductive adsorption between lignin and cellulase through increased electrostatic repulsion.

Sodium sulfite-driven Helicobacter pylori eradication: Unraveling oxygen dynamics through multi-omics investigation.

Due to the emergence and spread of multidrug resistance in Helicobacter pylori (H. pylori), its eradication has become difficult. Sodium sulfite (SS), a widely used food additive for ensuring food safety and storage, has been recognized as an effective nonbactericidal agent for H. pylori eradication. However, the mechanism by which H. pylori adapts and eventually succumbs under low- or no-oxygen conditions remains unknown. In this study, we aimed to evaluate the anti-H. pylori effect of SS and investigated the multiomics mechanism by which SS kills H. pylori. The results demonstrated that SS effectively eradicated H. pylori both in vitro and in vivo. H. pylori responds to the oxygen changes regulated by SS, downregulates the HcpE gene, which is responsible for redox homeostasis in bacteria, decreases the activities of enzymes related to oxidative stress, and disrupts the outer membrane structure, increasing susceptibility to oxidative stress. Furthermore, SS downregulates the content of cytochrome C in the microaerobic respiratory chain, leading to a sharp decrease in ATP synthesis. Consequently, the accumulation of triglycerides (TGs) in bacteria due to oxidative stress supports anaerobic respiration, meeting their energy requirements. The multifaceted death of H. pylori caused by SS does not result in drug resistance. Thus, screening of the redox homeostasis of HcpE as a new target for H. pylori infection treatment could lead to the development of a novel approach for H. pylori eradication therapy.

Sodium sulfite triggered hepatic apoptosis, necroptosis, and pyroptosis by inducing mitochondrial damage in mice and AML-12 cells.

Sodium sulfite (SS) is a biological derivative of the air pollutant sulfur dioxide, and is often used as a food and pharmaceutical additive. Improper or excessive SS exposure in liver cell death. The phenomenon of simultaneous regulation of apoptosis, necroptosis, and pyroptosis is defined as PANoptosis. However, the specific types of programmed cell death (PCD) caused by SS and their interconnections remain unclear. In the present study, C57BL/6 mice were orally administered SS for 30 d, consecutively, to establish an in vivo mouse exposure model. AML-12 cells were treated with SS for 24 h to establish an in vitro exposure model. The results showed that SS-induced mitochondrial reactive oxygen species (mtROS) accumulation activated the BAX/Bcl-2/caspase 3 pathway to trigger apoptosis and RIPK1/RIPK3/p-MLKL to trigger necroptosis. Interestingly, ROS-activated p-MLKL perforated not the cell membrane as well as the lysosomal membrane. We determined that p-MLKL mediates lysosomal membrane permeabilization (LMP), resulting in cathepsin B (CTSB) release. Furthermore, knockdown of MLKL, a CTSB inhibitor (CA074-ME) and an NLRP3 inhibitor (MCC950) alleviated SS-induced pyroptosis. In summary, our study showed that SS induced apoptosis and necroptosis though mtROS accumulation, whereas the activation of p-MLKL mediated NLRP3-dependent pyroptosis by causing CTSB leakage through LMP. This study comprehensively explored the mechanism unerlying SS-induced PCD and provided an experimental basis for p-MLKL as a potential regulatory protein in PANoptosis.

Sodium Sulfite-Triggered Hepatocyte Ferroptosis via mtROS/Lysosomal Membrane Permeabilization-Mediated Lysosome Iron Efflux.

Sodium sulfite is a widely used preservative in the food industry. Ferroptosis has been a newly discovered form of iron-dependent oxidative cell death in recent years. However, the potential connection between sodium sulfite and ferroptosis has not been explored. In our study, we observed the abnormal expression of ferroptosis marker protein in vivo, suggesting that sodium sulfite caused ferroptosis in vivo. Next, our study revealed that sodium sulfite caused the overproduction of mitochondrial reactive oxygen species (mtROS) in the AML-12 cells. It is well established that reactive oxygen species (ROS) can induce lysosomal membrane permeabilization. After lysosomal membrane permeabilization occurs, the outflow of Fe2+ in lysosomes triggers the Fenton reaction and subsequently results in the increase of intracellular ROS level, which is closely related to ferroptosis. As speculated, acridine orange (AO) staining and LysoTracker red staining showed that sodium sulfite-induced lysosomal membrane permeabilization could be alleviated by mtROS scavenger TEMPO. In addition, TEMPO, lysosomal stabilizer mannose, and lysosomal iron chelator deferoxamine (DFO) inhibited sodium sulfite-induced ferroptosis. Overall, the results showed that sodium sulfite induced lysosomal iron efflux through the mtROS-lysosomal membrane permeabilization pathway and eventually led to ferroptosis. Our study might provide a new mechanism for the hepatotoxicity of sodium sulfite and a theoretical basis for the risk assessment of sodium sulfite as a food additive.

The effects of sodium sulfite on Helicobacter pylori by establishing a hypoxic environment.

Helicobacter pylori (H. pylori) is an obligate microaerobion and does not survive in low oxygen. Sodium sulfite (SS) reacts and consume oxygen in solutions. The present study aimed to investigate the effects of SS on H. pylori. The effects of SS on oxygen concentrations in solutions and on H. pylori in vivo and in vitro were examined, and the mechanisms involved were explored. The results showed that SS decreased the oxygen concentration in water and artificial gastric juice. In Columbia blood agar and special peptone broth, SS concentration-dependently inhibited the proliferation of H. pylori ATCC43504 and Sydney strain-1 in Columbia blood agar or special peptone broth, and dose-dependently decreased the number of H. pylori in Mongolian gerbils and Kunming mouse infection models. The H. pylori was relapsed in 2 weeks withdrawal and the recurrence in the SS group was lower than that in the positive triple drug group. These effects were superior to positive triple drugs. After SS treatments, the cell membrane and cytoplasm structure of H. pylori were disrupted. SS-induced oxygen-free environment initially blocked aerobic respiration, triggered oxidative stress, disturbed energy production. In conclusion, SS consumes oxygen and creates an oxygen-free environment in which H. pylori does not survive. The present study provides a new strategy and perspective for the clinical treatment of H. pylori infectious disease.

Ammonia and sodium sulfite synergistically pretreat reed to enhance enzymatic saccharification.

Pretreatment is important to overcome the structural recalcitrance of reed (a viable energy grass) to produce fermentable sugar. Herein, the study reported the pretreatment of reed using different alkali chemicals (sodium hydroxide/anthraquinone, sodium hydroxide/sodium sulfite, sodium hydroxide/sodium sulfide, ammonia/hydrogen peroxide, triethanolamine, and ammonia/sodium sulfite). The comparative study showed that the pretreatment using ammonia and sodium sulfite (NS) performed the best among them. The NS pretreatment of reed was further optimized using the Response Surface Methodology (RSM). The results showed that about 90.36% lignin was removed when reed was pretreated with 10 wt% of ammonia and 10% of sodium sulfite at 172 °C for 20 min. The excellent lignin removal performance was attributable to the synergistic effects between ammonia and sodium sulfite. The NS pretreated reed achieved 85.6% of enzymatic hydrolysis efficiency and 64.83% of total sugar yield.

A novel and greener sequential column leaching approach for the treatment of two different Greek laterites.

Τhe present study investigates, from an environmental protection viewpoint, the efficiency of sequential column leaching of two different Greek laterites, i.e. a limonitic ore from central and a saprolitic ore from northern Greece. First, the most refractory limonitic laterite is leached in the first column for 15 days and the obtained pregnant leach solution (PLS) is further used for the leaching of the easier to treat saprolitic ore in the second column, thus achieving a significantly reduced acid consumption. The main parameters affecting the process efficiency, i.e. acid molarity (1.5 or 3 mol/L H2SO4) and addition of sodium sulfite (Na2SO3) in the leaching solution were studied. The extraction of Ni, Co, Fe, Al, Mg, Mn and Ca was determined by Atomic Absorption Spectroscopy (AAS), while the characterization of the ores and final residues was carried out by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA/DTA), and Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM-EDS) analysis. The results confirm the efficiency of the proposed green approach, which with the use of leaching solution containing 1.5 mol/L H2SO4 and 20 g/L Na2SO3 resulted in 73.8 % Ni, 71.6 % Co and 8.4 % Fe extraction after a short period of time (33 days), while the acid consumption, which is a serious environmental concern, was very low and did not exceed 300 kg/t ore. Overall, the proposed process not only improves the efficiency of leaching of different types of laterites for the recovery of both Ni and Co but also reduces the environmental impacts due to the significantly lower acid consumption.

Follow-up of the re-evaluation of sulfur dioxide (E 220), sodium sulfite (E 221), sodium bisulfite (E 222), sodium metabisulfite (E 223), potassium metabisulfite (E 224), calcium sulfite (E 226), calcium bisulfite (E 227) and potassium bisulfite (E 228).

Sulfur dioxide-sulfites (E 220-228) were re-evaluated in 2016, resulting in the setting of a temporary ADI of 0.7 mg SO2 equivalents/kg bw per day. Following a European Commission call for data, the present follow-up opinion assesses data provided by interested business operators (IBOs) and additional evidence identified in the publicly available literature. No new biological or toxicological data addressing the data gaps described in the re-evaluation were submitted by IBOs. Taking into account data identified from the literature search, the Panel concluded that there was no substantial reduction in the uncertainties previously identified in the re-evaluation. Therefore, the Panel considered that the available toxicity database was inadequate to derive an ADI and withdrew the current temporary group acceptable daily intake (ADI). A margin of exposure (MOE) approach was considered appropriate to assess the risk for these food additives. A lower confidence limit of the benchmark dose of 38 mg SO2 equivalents/kg bw per day, which is lower than the previous reference point of 70 mg SO2 equivalents/kg bw per day, was estimated based on prolonged visual evoked potential latency. An assessment factor of 80 was applied for the assessment of the MoE. At the estimated dietary exposures, when using a refined exposure scenario (Data set D), MOEs at the maximum of 95th percentile ranges were below 80 for all population groups except for adolescents. The dietary exposures estimated using the maximum permitted levels would result in MOEs below 80 in all population groups at the maximum of the ranges of the mean, and for most of the population groups at both minimum and maximum of the ranges at the 95th percentile. The Panel concluded that this raises a safety concern for both dietary exposure scenarios. The Panel also performed a risk assessment for toxic elements present in sulfur dioxide-sulfites (E 220-228), based on data submitted by IBOs, and concluded that the maximum limits in the EU specifications for arsenic, lead and mercury should be lowered and a maximum limit for cadmium should be introduced.

A Comparison of Cooking Conditions of Rhizoclonium Pulp as a Substitute for Wood Pulp.

The green macroalga Rhizoclonium was cooked with 5%, 10%, and 20% sodium hydroxide (NaOH) for 4 h (5-N, 10-N, and 20-N groups, respectively); with 5%, 10%, and 20% sodium sulfite (Na2SO3) for 4 h (5-NS, 10-NS, and 20-NS groups, respectively); and with 5%, 10%, and 20% NaOH for 2 h and 1% hydrogen peroxide (H2O2) for 2 h (5-NH, 10-NH, and 20-NH groups, respectively). The 5-NH handsheet showed the best mechanical properties; however, the 10-NH pulp was easier to separate than 5-NH during handsheet making, and 10-NH was more suitable for the industrial process. Thus, the 10-NH group showed the optimal production conditions with an optimal length/width ratio, crystallinity index (CI%), three-dimensional (3D) configuration, and mechanical strength. Substituting 20% 10-NH Rhizoclonium pulp with wood pulp had no significant effect on the mechanical properties of the 100% wood pulp handsheet. However, the fibers of the NS group were flatter and lost their 3D configuration, resulting in low mechanical strength. Overall, Rhizoclonium had its own optimal cooking condition, which was not the same as for wood pulp, and it has potential as a substitute for wood pulp in papermaking.

Bioremediation pretreatment of waste-activated sludge using microalgae Spirulina platensis derived biochar coupled with sodium sulfite: Performance and microbial community dynamics.

4-Nonylphenol is a typical endocrine-disrupting compound found in waste-activated sludge. This study evaluates the feasibility of blue-green algae (Spirulina platensis)-based biochar as a carbon-neutral material to improve sodium sulfite (S(IV))-mediated sludge purification. Blue-green algae-based biochar is an effective activator (at 500 °C and 3 × 10-6 M) of sodium sulfite and removed 75 % of 4-nonylphenol at pH 6 using at 1.7 g/L of dosage. Possible synergistic relationships among the coexisting oxidizing species (SO3•-, SO4•-, HO•, and 1O2), obvious defect structure, and abundant carbonyl oxygen groups on the surface of the biochar together dived advanced oxidation process. The bacterial consortia promoted the decomposition of biologically available substrates in the biosolid mixture, which led to the enrichment of Denitratisoma, and boosted 4-nonylphenol biodegradation. This study outlines a potential carbon-neutral, cost-effective, and sustainable sludge treatment strategy using renewable blue-green algae-based biochar, aiding 4-nonylphenol biodegradation in waste-activated sludge.

Sodium Sulfite-Induced Mast Cell Pyroptosis and Degranulation.

Sodium sulfite, a common food additive, has been proved to cause allergic reaction. Pyroptosis is an inflammatory form of programmed cell death with plasma membrane lysis. In this study, we found that sodium sulfite triggered pyroptosis, which depended on reactive oxygen species (ROS)/NOD-like receptor protein 3 (NLRP3) in RBL-2H3 mast cells. Sodium sulfite increased the generation of ROS and the expression of NLRP3, caspase-1, gasdermin D N-terminal (GSDMD-N), interleukin-1ß (IL-1ß), and interleukin-18 (IL-18). The ROS scavenger N-acetyl-L-carnosine (NAC) and the NLRP3 inhibitor MCC950 reversed these effects. Furthermore, using a lactate dehydrogenase kit, propidium iodide staining, scanning electron microscopy, colocalization of GSDMD-N with histamine, and neutral red staining, we found that sodium sulfite notably induced cell membrane rupture. Because ß-Hexosaminidase and histamine play a key role in allergic reactions, we detected the release of ß-Hexosaminidase and histamine. The data showed that the release of ß-Hexosaminidase and histamine induced by sodium sulfite was increased with dose independence, which were inhibited after treatment with NAC or MCC950. Overall, evidence suggested that pyroptosis induced by sodium sulfite may rupture the cell membrane and result in degranulation of mast cells. Our study may provide new insights for the mechanism by which sodium sulfite induces mast cell death and sensitization.

Sodium sulfite causes gastric mucosal cell death by inducing oxidative stress.

Sulfites are commonly used as a preservative and antioxidant additives in the food industry. Sulfites are absorbed by the gastrointestinal tract and distributed essentially to all body tissues. Although sulfites have been believed to be safe food additives, some studies have shown that they exhibit adverse effects in various tissues. In this study, we examined the cytotoxic effect of sodium sulfite (Na2SO3) against rat gastric mucosal cells (RGM1) and further investigated its underlying molecular mechanism. We demonstrated that exposure to Na2SO3 exerts significant cytotoxicity in RGM1 cells through induction of oxidative stress. Exposure of RGM1 cells to Na2SO3 caused a significant formation of protein carbonyls and 8-hydroxy-2'-deoxyguanosine, major oxidative stress markers, with a concomitant accumulation of carbonylated protein-related aggregates. Furthermore, we found that incubation of lysozyme with Na2SO3 evokes protein carbonylation and aggregation via the metal ion-catalyzed free radical formation derived from Na2SO3. Our results suggest that Na2SO3 might lead to gastric tissue injury via induction of oxidative stress by the formation of Na2SO3-related free radicals.

Sodium sulfite (SoS) as decontamination strategy for Fusarium-toxin contaminated maize and its impact on immunological traits in pigs challenged with lipopolysaccharide (LPS).

The main objective of this study was to evaluate the effects of sodium sulfite (SoS) treatment of maize and its impact on the porcine immune system in the presence of an LPS-induced systemic inflammation. Control maize (CON) and Fusarium-toxin contaminated maize (FUS) were wet-preserved (20% moisture) for 79 days with (+) or without (-) SoS and then included at 10% in a diet, resulting in four experimental groups: CON-, CON+, FUS-, and FUS+ with deoxynivalenol (DON) concentrations of 0.09, 0.05, 5.36, and 0.83 mg DON/kg feed, respectively. After 42-day feeding trial (weaned barrows, n = 20/group), ten pigs per group were challenged intraperitoneally with either 7.5 µg LPS/kg BW or placebo (0.9% NaCl), observed for 2 h, and then sacrificed. Blood, mesenteric lymph nodes, and spleen were collected for phenotyping of different T cell subsets, B cells, and monocytes. Phagocytic activity and intracellular formation of reactive oxygen species (ROS) were analyzed in both polymorphonuclear cells (PMN) and peripheral blood mononuclear cells (PBMC) using flow cytometry. Our results revealed that the impact of DON was more notable on CD3+CD4+CD8+ T cells in lymphoid tissues rather than in blood T cells. In contrast, SoS treatment of maize altered leukocyte subpopulations in blood, e.g., reduced the percentage and fluorescence signal of CD8high T cells. Interestingly, SoS treatment reduced the amount of free radicals in basal ROS-producing PMNs only in LPS-challenged animals, suggesting a decrease in basal cellular ROS production (pSoS*LPS = 0.022).

Mechanism analysis of toxicity of sodium sulfite to human hepatocytes L02.

Food additives are widely used in various food products to preserve the taste, color, and other qualities. However, if they are used improperly or exceed the standard, they will cause damage to the human body. Sulfite is a commonly used food additive to prevent oxidation from deteriorating the nutrients in foods, it has been widely used as a bleaching agent in the food industry for a long time. In this study, human hepatocytes L02 cells were used as a model cell line to evaluate the toxicity of sodium sulfite. The cell morphology and cell proliferation were affected by sodium sulfite treatment, and apoptosis was detected. Transcriptome sequencing showed 97 differentially expressed genes (DEGs) between the experimental group (IC50) and the control group (MOCK), and 27 differentially expressed genes related to cell apoptosis, metabolism and inflammation were selected for validation by qPCR. Among them, 13 significantly upregulated genes and 14 significantly downregulated genes were identified by qPCR. The results showed that with increase of sodium sulfite concentration, the morphology of L02 changed, cell proliferation and activity were inhibited, and sodium sulfite caused apoptosis in a concentration- and time-dependent manner. The resulting toxic mechanism inhibits proliferation, damages the mitochondrial integrity, and promotes apoptosis.

Combined effect of two-liquid silane-phosphate primer and single-liquid sodium sulfite primer on bonding between self-polymerizing resins and feldspathic ceramics.

The purpose of this study is to investigate the combined effect of two-liquid silane-phosphate primer and single-liquid sodium sulfite primer on bonding between self-polymerizing resins and feldspathic ceramics, and to promote the polymerization behavior of self-polymerizing resins at the bonding interface. The silane-phosphate primer (Super-Bond PZ Primer; PZ) and the sodium sulfite primer (Teeth Primer; TP) were used as the surface treatment agents for bonding the feldspathic ceramics and the self-polymerizing resins (MMA-TBB resin and 4-META/MMA-TBB resin). Combined PZ and TP showed high shear bond strengths. The peak of the differential scanning calorimetry curve was shown to occur early through the addition of TP. These results indicated that additional TP promoted the conversion in the initial polymerization of resin, and the firmly bond was obtained at the interface. PZ+TP treatment can be regarded as an effective treatment for a temporary splint used in teeth restoration.

A High Barrier and Sustained Release Oxygen-Absorbing Ionic Polymer for Food Packaging Applications.

Development and utilization of oxygen absorbing materials for food and beverage packaging are important to protect the oxygen-sensitive foods. In this study, we developed a kind of ionic polymer with excellent oxygen absorbing ability based on reacting ethylene-acrylic acid copolymer (EAA) and sodium sulfite (Na2 SO3 ). By virtue of the hydrophilicity of the ionic polymer, the sulfite in Na2 SO3 is easily hydrolyzed and ionized. The oxygen inhalation reaction was gradually initiated and started, whereas achieved a slow and controllable oxygen absorption process. The oxygen absorbing agent can be directly added in the form of an auxiliary agent, which greatly simplifies the preparation process of the oxygen absorbing material. Furthermore, the ionic structure of the EAA/Na2 SO3 composites were destroyed and mechanical properties of the material did not decrease after oxygen absorption. More importantly, it can effectively prevent the entry of external oxygen because the ionic polymer itself has better barrier properties. PRACTICAL APPLICATION: Typical oxygen-sensitive objects include: beer, coffee, canned food, meat products, dairy products, and so on. The presence of oxygen in the package can cause microbial growth, odor generation, color change and nutrient loss, resulting in a significant reduction in food shelf life. Therefore, controlling the oxygen content of the food package is important to limit the rate of these spoilage and spoilage reactions in the food. Materials with active oxygen scavenging and good barrier properties and packaging performance are highly economically viable in terms of improving product quality and reducing packaging costs.

Clearing up the oxygen dip in HPAEC-PAD sugar analysis: Sodium sulfite as an oxygen scavenger.

A baseline dip caused by the reduction of dissolved oxygen in samples has been a source of trouble in the analysis of major monosaccharides (galactose, glucose, mannose, and fructose) in the high-performance anion-exchange chromatography with pulsed amperometric detection system. This study attempted three different methods to remove the baseline dip from the resulting chromatograms, and among the approaches, sodium sulfite was found to act as the best oxygen scavenger. Clean chromatograms were obtained by adding at least 3 mg/mL sodium sulfite to samples, which removed the baseline dip and improved the accuracy of sugar analysis. Although sodium sulfite does not influence analytical sensitivity, it can cause a reduction of sugar retention; however, retention time can be recovered by washing with 200 mM sodium hydroxide solution. Results demonstrated that sodium sulfite is an effective means either to remove the baseline dip for low concentration analysis under 1 mg/L, or to separate the target sugar from the baseline dip by retention time rearrangement.

[Removal Efficiency of Trichloroacetamide by UV/Sodium Sulfite].

Haloacetamides (HAcAms) are an emerging class of nitrogenous disinfection by-products (N-DBPs) with high cytotoxicity and genotoxicity, which are widely detected in drinking water. The toxicity of trichloroacetamide (TCAcAm) is significantly higher than traditional DBPs. In this study, ultraviolet (UV) treatment was combined with sodium sulphite (Na2SO3) to remove TCAcAm from water. The effects of different light intensities, different agent dosages (Na2SO3), and pH conditions on the removal of TCAcAm by UV/Na2SO3 advanced reduction process were investigated. The results showed that TCAcAm could be rapidly degraded by the UV/Na2SO3 system. The degradation effect was directly proportional to light intensity, dosage of Na2SO3, and pH. Moreover, the pH had a significant effect on the reaction rate and degradation rate. As the pH increased from 6 to 9, the degradation rate of TCAcAm increased from 12.8% to 99.6%, in 120 min. The removal rate of TCAcAm reached 99.4% when the UV light intensity, pH, Na2SO3 dosage, and reaction time were 450 µW·cm-2, 9, 1.00 mmol·L-1, and 30 min, respectively. The experimental results indicated that the UV/Na2SO3 system is an efficient advanced reduction process for the removal of TCAcAm, and it has the potential to reduce other halogenated DBPs. Therefore, it could be used for the degradation of halogenated DBPs in the treatment of drinking water.