Impact Of Hydrogen Peroxide Research Articles

Treatment of Organic Pollutant by Advanced Oxidation Processes

The investigation involved the oxidation of urea (UR) in a batch reactor, employing Fenton's reagent. Various parameters, namely reaction time, pH level, ferrous ion dose, and hydrogen peroxide dose, were scrutinized. The reaction time spanned from 30 minutes to 3 hours, revealing a notably positive impact. An optimal pH of 3 was identified for the medium. The concentrations of ferrous ions ranged from 0.2 g/l to 0.53 g/l, with hydrogen peroxide levels ranging from 1 g/l to 2.65 g/l. The impact of hydrogen peroxide was notably significant at a ferrous ion concentration of 0.3 g/l and a pH of 3. Evaluating urea removal efficiency through chemical oxygen demand (COD) calculations showed a maximum efficiency of 86.8%, with a minimum ammonia yield of 6%. Overall, the outcomes underscored the efficacy of the Fenton process in urea treatment.

Methionine oxidation of carbohydrate-active enzymes during white-rot wood decay.

White-rot fungi employ secreted carbohydrate-active enzymes (CAZymes) along with reactive oxygen species (ROS), like hydrogen peroxide (H2O2), to degrade lignocellulose in wood. H2O2 serves as a co-substrate for key oxidoreductases during the initial decay phase. While the degradation of lignocellulose by CAZymes is well documented, the impact of ROS on the oxidation of the secreted proteins remains unclear, and the identity of the oxidized proteins is unknown. Methionine (Met) can be oxidized to Met sulfoxide (MetO) or Met sulfone (MetO2) with potential deleterious, antioxidant, or regulatory effects. Other residues, like proline (Pro), can undergo carbonylation. Using the white-rot Pycnoporus cinnabarinus grown on aspen wood, we analyzed the Met content of the secreted proteins and their susceptibility to oxidation combining H218O2 with deep shotgun proteomics. Strikingly, their overall Met content was significantly lower (1.4%) compared to intracellular proteins (2.1%), a feature conserved in fungi but not in metazoans or plants. We evidenced that a catalase, widespread in white-rot fungi, protects the secreted proteins from oxidation. Our redox proteomics approach allowed the identification of 49 oxidizable Met and 40 oxidizable Pro residues within few secreted proteins, mostly CAZymes. Interestingly, many of them had several oxidized residues localized in hotspots. Some Met, including those in GH7 cellobiohydrolases, were oxidized up to 47%, with a substantial percentage of sulfone (13%). These Met are conserved in fungal homologs, suggesting important functional roles. Our findings reveal that white-rot fungi safeguard their secreted proteins by minimizing their Met content and by scavenging ROS and pinpoint redox-active residues in CAZymes.IMPORTANCEThe study of lignocellulose degradation by fungi is critical for understanding the ecological and industrial implications of wood decay. While carbohydrate-active enzymes (CAZymes) play a well-established role in lignocellulose degradation, the impact of hydrogen peroxide (H2O2) on secreted proteins remains unclear. This study aims at evaluating the effect of H2O2 on secreted proteins, focusing on the oxidation of methionine (Met). Using the model white-rot fungi Pycnoporus cinnabarinus grown on aspen wood, we showed that fungi protect their secreted proteins from oxidation by reducing their Met content and utilizing a secreted catalase to scavenge exogenous H2O2. The research identified key oxidizable Met within secreted CAZymes. Importantly, some Met, like those of GH7 cellobiohydrolases, undergone substantial oxidation levels suggesting important roles in lignocellulose degradation. These findings highlight the adaptive mechanisms employed by white-rot fungi to safeguard their secreted proteins during wood decay and emphasize the importance of these processes in lignocellulose breakdown.

The Impact of Hydrogen Peroxide (H2O2) Fumigation on Bacterial Levels in Dental Office Environments: A Randomized Clinical Trial Investigation.

Fumigation with hydrogen peroxide has proven to be a highly effective approach to maintaining biological safety within dental offices. The main purpose of this research was to investigate the efficacy of hydrogen peroxide (H2O2) fumigation in reducing bacterial levels in dental office environments. The study involved 30 participants diagnosed with moderate caries decay (ICDAS 3 and 4) in their mandibular molars. Sixty Petri dishes (two per patient) with Columbia Agar and 5% Sheep Blood were opened at the beginning of the caries treatment. After the completion of caries treatment and tooth restoration, 30 plates (G1 group) were closed. Following this, a 20 min fumigation procedure with 6% hydrogen peroxide biosanitizer using a compressed air device was conducted. After the fumigation, the remaining plates were closed (G2 group). The total number of bacteria CFUs (colony-forming units) in the dental office air was determined using the Koch sedimentation method. The total bacterial colony (TBC) level, measured in cfu/m3, demonstrated a significant decrease in the number of bacteria following room environment fumigation (163.1 ± 145.7; G2 group) compared to non-fumigated samples (817.2 ± 208.2; G1 group) (p < 0.001). The predominant bacteria observed in the microbiological plates before fumigation were Micrococcus and Bacillus species, found in 80% (24/30) and 60% (18/30) of the plates, respectively. Application of H2O2 room fumigation resulted in a significant reduction in bacterial numbers: 79.2% (5/30) for Micrococcus species (p < 0.001), 83.3% (3/30) for Bacillus species (p < 0.001), and 100% (0/30) for Staphylococcus arlettae (p < 0.05). Fumigation with 6% H2O2 is an effective method for reducing bacterial counts in a dental office environment.

Impact of hydrogen peroxide on structure, stability, and aggregational properties of human γS-crystallin

Cataract is the leading cause of blindness worldwide. Oxidative stress is one of the known risk factors for agerelated cataracts. The present study was designed to understand the effect of H2O2-induced oxidative stress on human γS-crystallin and its relationship to lens opacification and cataract. Human γS-crystallin cDNA was cloned into the pET-20b vector, overexpressed in BL21 Star (DE3) cells, and was purified using ion-exchange and gel filtration chromatography. The structure, stability, and aggregational properties of human γS-crystallin under H2O2 stress were studied using fluorescence and circular dichroism spectroscopy methods. H2O2 treatment did not show any significant effect on the γS-crystallin secondary structure but showed an effect on its tertiary structure, resulting in N'-formylkynurenine formation. The H2O2-treated sample showed increased surface hydrophobicity, was less stable, and opened its Greek key motifs earlier with a midpoint of thermal unfolding curve (Tm) of 70.2°C compared with untreated γS-crystallin (Tm=71.4°C). The sample treated with H2O2 aggregated earlier in response to heating at 65°C. H2O2-induced oxidative stress alters the tryptophan microenvironment and the surface hydrophobicity of γS-crystallin, and these changes decrease its thermal stability and increase its tendency to aggregate, consistent with its role as a risk factor in age-related cataract.

Impact of Hydrogen Peroxide on Protein Synthesis in Yeast.

Cells must be able to respond and adapt to different stress conditions to maintain normal function. A common response to stress is the global inhibition of protein synthesis. Protein synthesis is an expensive process consuming much of the cell’s energy. Consequently, it must be tightly regulated to conserve resources. One of these stress conditions is oxidative stress, resulting from the accumulation of reactive oxygen species (ROS) mainly produced by the mitochondria but also by other intracellular sources. Cells utilize a variety of antioxidant systems to protect against ROS, directing signaling and adaptation responses at lower levels and/or detoxification as levels increase to preclude the accumulation of damage. In this review, we focus on the role of hydrogen peroxide, H2O2, as a signaling molecule regulating protein synthesis at different levels, including transcription and various parts of the translation process, e.g., initiation, elongation, termination and ribosome recycling.

Impact of hydrogen peroxide on microalgae cultivated in varying salt-nitrate-phosphate conditions

Microalgal biomass has received a great deal of attention as renewable and environmental-friendly biofuel feedstock as a rebuttal to climate change, energy crisis, and global warming. To improve the commercial viability of algal biodiesel production, the rise in lipid accretion and the enrichment of algal fatty acid profile are of utmost importance. In this experiment, lipid content and fatty acid methyl ester profiling of the microalgal strain, Scenedesmus sp. is done to understand the intercalating effect of different media composition for its suitability in context to biodiesel production. Various nutrient combinations (sodium nitrate, NaNO3) and di-potassium hydrogen phosphate, (K2HPO4) were incorporated along with salinity (sodium chloride) exposure for first 48 h stage of algal cultivation, followed by oxidative stress via hydrogen peroxide (H2O2) for the second 24 h stage of cultivation. The results show that the presence of 100 mM NaCl, 35.29 mM NaNO3, and 5.74 mM K2HPO4 followed by the addition of 10 mM H2O2 (S100H10N35.29P5.74) to the algal growth media led to the accumulation of maximum total lipid content (226.49 ± 16.6 μg/mg). Another nutrient combination, S0H10N35.29P0, increased the saturated fatty acid composition (C16:0) to 31.7%. Principal component analysis (PCA) also demonstrated the combined effect of multiple nutrient components and their relative concentrations on the growth parameters and algal biochemical profile, such as biomass, chlorophyll, lipid, carbohydrate, alongwith fatty acid profiling. Hence, this study demonstrate the potential of Scenedesmus sp. in response to a multi-component stress environment that has influenced the fate of fatty acid methyl esters (FAME) composition and significantly improved the quality of algal biofuels produced over a short period.

Effects of Hydrogen Peroxide on Organically Fertilized Hydroponic Lettuce (Lactuca sativa L.)

Hydroponic production typically uses conventional fertilizers, but information is lacking on the use of organic hydroponic fertilizers. Development of microbial communities and biofilm that can reduce dissolved oxygen availability is a difficulty with organic hydroponics. One potential solution is the use of hydrogen peroxide (H2O2) which can reduce microbial populations and decompose to form oxygen. However, information is lacking on the impact of hydrogen peroxide on hydroponic crop performance. The aim of this study was to determine the effects of H2O2 concentrations in deep water culture hydroponics by assessing how it affects plant size and yield in lettuce (Lactuca sativa L.) “Rouxai”. In this experiment, three H2O2 treatments, namely the application of 0, 37.5 or 75 mg/L H2O2 to 4 L aerated hydroponic containers with either conventional or organic fertilizer, were compared. The containers had either fish-based organic fertilizer (4-4-1, N-P2O5-K2O) or inorganic mineral based conventional nutrient solution (21-5-20, N-P2O5-K2O), both applied at 150 mg/L N. Three replicates of each H2O2 treatment–fertilizer combination were prepared resulting in a total of eighteen mini hydroponic containers each with one head of lettuce. There were two growth cycles: fall 2018 and spring 2019. When added to conventional fertilizers, both 37.5 mg/L and 75 mg/L of H2O2 led to stunted growth or death of lettuce plants. However, when 37.5 mg/L of H2O2 was applied to organic fertilizers, the lettuce yield nearly matched that of the conventionally fertilized control, demonstrating that the application of H2O2 has the potential to make organic hydroponic fertilization a more viable method in the future.

Genome-wide impact of hydrogen peroxide on maintenance DNA methylation in replicating cells

BackgroundEnvironmental factors, such as oxidative stress, have the potential to modify the epigenetic landscape of cells. We have previously shown that DNA methyltransferase (DNMT) activity can be inhibited by sublethal doses of hydrogen peroxide (H2O2). However, site-specific changes in DNA methylation and the reversibility of any changes have not been explored. Using bead chip array technology, differential methylation was assessed in Jurkat T-lymphoma cells following exposure to H2O2.ResultsSublethal H2O2 exposure was associated with an initial genome-wide decrease in DNA methylation in replicating cells, which was largely corrected 72 h later. However, some alterations were conserved through subsequent cycles of cell division. Significant changes to the variability of DNA methylation were also observed both globally and at the site-specific level.ConclusionsThis research indicates that increased exposure to H2O2 can result in long-term alterations to DNA methylation patterns, providing a mechanism for environmental factors to have prolonged impact on gene expression.

Impact of Hydrogen Peroxide and Albumin on the Corrosion Behavior of Titanium Alloy (Ti6Al4V) in Saline Solution

Impact of Hydrogen Peroxide and Albumin on the Corrosion Behavior of Titanium Alloy (Ti6Al4V) in Saline Solution

Impact of H2O2 on the Lactic and Formic Acid Degradation in Presence of TiO2 Rutile and Anatase Phases under UV and Visible Light

The degradation rates of formic acid and lactic acid in the presence and absence of H2O2 were studied, utilizing several TiO2 catalysts: PC105 (100% anatase), MPT 625 (100% rutile), and P25 (80% anatase/20% rutile), and the results were discussed with regards to the current literature. The impact of hydrogen peroxide on the photocatalytic efficiency of eleven TiO2 samples was then determined, using commercial anatase structures (PC105, PC500, UV100), commercial mixed anatase/rutile (P25 and P90), and six rutile (two commercial samples: MPT 625 and C-R160, and four home-made rutile samples were synthesized by TiCl4 hydrolysis). The effect of catalyst surface area and TiO2 phase on the degradation rate of lactic acid (LA) and the decomposition of H2O2 was studied and discussed in regard to the active species generated. The intermediate products formed in the absence and presence of H2O2 were also an important factor in the comparison. Finally, the efficiency of the degradation of LA and formic acid (FA) in the presence of rutile and H2O2 was determined under visible light, and their reactivity was compared. The intermediate products formed in the degradation of LA were identified and quantified and compared to those obtained under UV (Ultra-Violet).

Impact of Hydrogen Peroxide and Copper Sulfate on the Delayed Release of Microcystin

Algicides, like hydrogen peroxide and copper sulfate, are commonly applied to recreational waters and drinking water sources to mitigate cyanobacterial blooms. In this work, the effects of hydrogen peroxide and copper sulfate were evaluated in two natural bloom samples (collected from Canadian and American waterbodies) and one lab-cultured Microcystis aeruginosa suspended in Colorado River water. Five algicide to dissolved organic carbon (DOC) dose ratios were evaluated during an initial exposure period of 24 h. One dose ratio (0.4 H2O2:DOC or 0.25 CuSO4:DOC) was then evaluated during stagnation after quenching (hydrogen peroxide) or extended exposure (copper sulfate) for up to 96 or 168 h. During the initial hydrogen peroxide exposure, the CA bloom had no release of intracellular microcystins (MCs) and the USA bloom only released MC at 4 H2O2:DOC. The reverse occurred with copper sulfate, where the CA bloom released MCs at 0.6 CuSO4:DOC but the USA bloom had no detectable extracellular MCs. Extracellular MC was released from the lab-cultured Microcystis at the lowest hydrogen peroxide and copper sulfate doses. In the hydrogen peroxide stagnation experiment, intracellular MC decreased in the USA bloom after 168 h despite the low dose applied. Similarly, the extended copper sulfate exposure led to intracellular MC decreases in both bloom samples after 168 h, despite showing no impact during the initial 24 h monitoring period. The lab-cultured Microcystis was again less resistant to both algicides, with releases observed after less than 2 h of stagnation or exposure. The damage to cells as measured by pigments during these experiments did not match the MC data, indicating that blooms with depressed pigment levels can still be a risk to nearby drinking water sources or recreational activities. These results provide insight on the timeline (up to one week) required for monitoring the potential release of MCs after algicide application.

Impact of Hydrogen Peroxide on the Secondary Metabolites, Enzyme Activities and Photosynthetic Pigment Accumulation of Vigna unguiculata L. (Walp)

The effects of exogenous application of hydrogen peroxide on the secondary metabolites, enzyme activities and photosynthetic pigment accumulation of Vigna unguiculata was investigated. The hereby study was carried out under a screen house to minimize extraneous factors. The experiment was laid down in completely randomized design (CRD) with eight replicates. After two weeks of sowing when the seedlings become fully established, the sample pots were divided into two regimes. The first regimes were supplied daily with 500 mL of 0.1 mM of hydrogen peroxide and the second regime was watered daily with tap water. After fifth week of sowing, the leaves of Vigna unguiculata from each regime were randomly selected and harvested. Secondary metabolites, enzyme assay and photosynthetic pigment screening was carried out on the harvested leaves. The impact of hydrogen peroxide on the parameters studied was done using one way analysis of variance. Mean values were separated using Fisher’s LSD at p≤0.05. The results showed that hydrogen peroxide strongly increased the accumulation of secondary metabolites such as flavonoids, glycosides, saponins, carbohydrates and alkaloids. It also induced α-amylase and lipase activities than the control plants and promotes the accumulation and biosynthesis of chlorophylls and carotenoids. In conclusion, hydrogen peroxide could be used as potential molecule to improve some secondary metabolites (flavonoids, glycosides, saponins, carbohydrates and alkaloids), α-amylase and lipase activities and photosynthetic pigments.

Introduction Pages

Notulae Scientia Biologicae (http://www.notulaebiologicae.ro), Issue 3, Volume 11, 2019: The papers published in this issue (https://www.notulaebiologicae.ro/index.php/nsb/issue/view/265) represent interesting novelties in different topics of life science. Among the exciting researches, we invite readers to find news about: pharmacological uses and health benefits of ginger (Zingiber officinale) in traditional Asian and ancient Chinese medicine, and modern practice; middle east respiratory syndrome: its occurrence, aetiology, epidemiology, associated clinicopathological findings, diagnosis, prevention and control in humans and animals; ethanolic extract of Chrysophyllum albidum stem bark prevents alloxan-induced diabetes; prevalence of group a rotavirus, some risk factors and clinical signs of the infection in children under five years in Yobe State, Nigeria; prevalence of increased serum urea and creatinine levels in dogs; impact of heat stress on blood and serum biochemistry parameters in rats; acute and sub-acute toxicity of Ganoderma applanatum (Pres.) Pat. extract mediated silver nanoparticles on rat; in-vitro control of oral thrush causal organisms using medicinal plants extracts; generic salmonella in asymptomatic adult volunteers: occurrence, antibiogram, extended-spectrum β-lactamase production and carbapenem resistance; impact of hydrogen peroxide on the secondary metabolites, enzyme activities and photosynthetic pigment accumulation of Vigna unguiculata L. (Walp); diversity, distribution and conservation status of the genus Tectaria Cav. from Deccan Peninsula and western Ghats of India.

Влияние окислительного стресса на нейротоксический эффект ацетаминофена

Paracetamol (acetaminophen, APAP) is a commonly-used antipyretic and analgesic. However, there have been reports indicating possible link between its use in pregnancy and impaired neuropsychic development in children. A number of prospective studies of the possible negative effect of acetaminophen on the development of a child after his mother took this drug during pregnancy, as well as the results of studies on glioma cells and neurons in murine cortex, may indicate presence of the neurotoxic effect of acetaminophen. It is currently unclear if paracetamol itself being pharmacologically active neurotropic substance, or its metabolites, one of which – NAPQI (N-acetyl-p-benzoquinone imine) known by its toxic effects in mitochindria, play the most significant role in proposed neurotoxicity. Therefore it seems important to study each metabolite separately. The ability of acetaminophen(paracetamol) in concentrations of 1 mg/ml and 2 mg/ml to reduce cell viability was shown on cells of the PC12 neuronal line using MTT-method, which is based on the ability of mitochondria of viable cells to restore formazan 3-(4,5-dimethylthiazole)-2,5-diphenyl-2-tetrazolium bromide (MTT). Concentrations of 0.125 mg/ml, 0.25 mg/ml and 0.5 mg/ml had no similar impact on cell culture viability. In addition, the impact of hydrogen peroxide (as an inducer of oxidative stress) on the neurotoxic effect of acetaminophen was studied. We demonstrated that in the presence of 0.3 mM or 0.5 mM hydrogen peroxide and acetaminophen in concentrations of 1 mg/ml and 2 mg/ml reliably reduced the percentage of surviving cells. We showed that the decrease of the viability of the cells of the PC12 neuronal line is obvious only after exposure to high concentrations of acetaminophen, especially in the presence of hydrogen peroxide, which means that neurotoxic effect is not likely to occur in vivo.

Impact of Hydrogen Peroxide on the UVC Photolysis of Diclofenac and Toxicity of the Phototransformation Products

The aim of this study was to investigate the effect of hydrogen peroxide on the UVC photolysis of diclofenac (DCF) in aqueous solution. The experimental results confirmed very high effectivity of UVC direct photolysis of diclofenac. Moreover, it was found that H2O2/UV only slightly improved photodegradation; however, the addition of hydrogen peroxide into the reaction system affected the mechanism of DCF decomposition. Kinetics of the DCF reaction with ⋅OH radicals in the UV/H2O2 process was determined. For both processes, namely, photolysis and UV/H2O2, an in-depth analysis focused on the formation of phototransformation products of DCF (TPs) was performed. To the best of our knowledge, such comprehensive comparison of diclofenac photodegradation via UVC photolysis and UV/H2O2 has not been presented so far. Although there were no significant differences with regard to the rate of diclofenac degradation by photolysis and UV/H2O2, different oxidation products were found to be associated with the two considered processes. Furthermore, the H2O2/UV treatment increased toxicity towards Vibrio fischeri, while direct UVC photolysis had no significant effect on toxicity. The increase in toxicity can be attributed to the breakdown of DCF and formation of much more toxic TPs in the course of the H2O2/UVC process.

Impact of Hydrogen Peroxide on Photocatalytic Destruction of Anionic SAS in a Reactor with Immobilized TiO2

Using sodium dodecylbenzenesulfonate the article showed high efficiency of photocatalytic system H2O2/TiO2/UV for deep destruction (~ 90% in terms of TOC) of anionic SAS in a aqueousmedium (C0 = 50 mg/dm3, pH0 5.9) in a reactor containing wide–porous ceramic block with immobilized TiO2 on its surface. The TiO2 film for a long time preserved a stable photocatalytic activity

The Impact of Hydrogen Peroxide as An Oxidant for Solvent-free Liquid Phase Oxidation of Benzyl Alcohol using Au-Pd Supported Carbon and Titanium Catalysts

The solvent free oxidation of benzyl alcohol was conducted employing Au and Pd supported catalysts, while utilizing hydrogen peroxide 35% (H2O2) as the oxidant, H2O2 is very cheap, mild, and an environment friendly reagent, which produced water as the only by-product. Various proportions of Au-Pd catalysts on carbon and titanium oxide activated as supports were synthesized through the use of sol immobilization catalyst synthesis technique. Characterization of the synthesized catalysts was performed using X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM). It was found that the synthesized Au-Pd/ activated carbon catalyst was beneficial for the solvent free oxidation of benzyl alcohol after its containing high surface area measuring 871 m2g-1. Analysis of the TEM data and particle dimension revealed smaller and narrower particle size of 1 wt%. Thus, the distribution of Au-Pd/C was attained. Carbon-supported bimetallic catalysts presented a higher conversion compared to catalysts that are supported titanium oxide (TiO2) for for the oxidation reaction of benzyl alcohol. It was determined that this technique was a suitable process for catalyst synthesis with high selectivity, same distribution of the particle size and activations.

Lowering treatment temperature reduces salmon mortality: a new way to treat with hydrogen peroxide in aquaculture.

In the article “Lowering treatment temperature reduces salmon mortality: a new way to treat with hydrogen peroxide in aquaculture” (DOI: 10.1002/ps.4751) [1], published in Wiley Online Library on 13 November 2017 and in Pest Management Science 535–540, reference 26 is partially incorrect. The correct reference should be: 26 Aaen SM, Aunsmo A and Horsberg TE, Impact of hydrogen peroxide on hatching ability of egg strings from salmon lice (Lepeophtheirus salmonis) in a field treatment and in a laboratory study with ascending concentrations. Aquaculture 422–423:167–171 (2014). The authors apologise for the oversight.

Hydrogen Peroxide Induced Protein Oxidation During Storage and Lyophilization Process

Although the impact of hydrogen peroxide (HP) on proteins in liquid solutions has been studied extensively, the impact during lyophilization has been largely overlooked. The purpose of this work was to investigate the effect of HP on lyophilized proteins and HP removal by lyophilization. A protein formulation at 5 mg/mL and its placebo were spiked with HP up to 5.0 ppm and then lyophilized. HP concentration, protein oxidation, and aggregation were monitored before and after lyophilization, as well as during storage at 25°C. The lyophilization process removed on average 94.1% of HP from protein formulation, but only 72.5% from the placebo. There were also significant increases in protein oxidization and aggregation. The oxidation increment correlated with the decrease of HP concentration in both the protein formulation and placebo at all temperatures. Protein oxidation at different freezing temperatures was also studied in follow-up studies. Data from these studies suggest that (1) HP has a significant impact on oxidation and aggregation of protein during lyophilization; (2) significant oxidation can occur even when the protein formulation is frozen; (3) the oxidized protein is more prone to aggregation during lyophilization process.

Comparison of Hydrogen Peroxide to Ammonium Ions and Sulfite as a Free Chlorine Quenching Agent for Disinfection By-Product Measurement

AbstractHydrogen peroxide is a potential dechlorinating agent that can preserve chlorinated drinking water samples for the determination of disinfection by-products (DBPs). The impact of hydrogen peroxide on the storage of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and adsorbable organic halides (AOX) generated by chlorination in a model of natural water was investigated and compared with parallel samples quenched by sodium sulfite and ammonium sulfate. Positive errors of up to 9 μg/L for THMs, 19 μg/L for HAAs, 1 μg/L for HANs, and 22 μg Cl/L for AOX were found after adding ammonium and storing for 9 days at 4°C, primarily due to the continued formation of chloroform, bromodichloromethane, dichloro- and trichloro-acetic acids, and dichloroacetonitrile. Hydrogen peroxide and sulfite led to smaller errors in the determination of THMs, HAAs, and AOX, while HANs degraded in the presence of sulfite. Hydrogen peroxide was the most suitable dechlorinating agent of these three...