Reducing Reagent Research Articles

Application of aluminum nanoparticles in reagents for oil viscosity reduction

The problem of extracting hard-to-recover reserves, which belong to the category of heavy and highly bound oil, is one of the most pressing oil industries. Many mining companies actively use physical and chemical methods to solve this problem. The use of nanotechnology in physical and chemical methods for increasing oil production is a relatively new area. Nanoparticles easily enter the regime, their size allows them to spread more easily in porous media without reducing permeability. The main goal of the research was to reduce oil viscosity and achieve increased production. In order to increase oil recovery, the proposed method for reducing oil viscosity in reservoir conditions based on treating the bottomhole zone of production wells with a solution of caustic soda and nanoparticles affects the dimension of 40-60 nm (concentrations of 1, 0.1 and 0.01 %). The nanoparticles were obtained using an electrical conductor method and studied by transmission electron microscopy. Determination of surface tension using a DSA30 device (Kruss, Germany) using the pendant drop (PD) method. The samples for testing were oil samples, visible wells No. 222761 Binagadi-North, No. 220051 Fatmai area and No. 221937 Kirmaki area, trading company "Binagadi Oil". Based on experimental data, it was found that the proposed composition reduces the viscosity of oil by several times in all three experimental samples, nanoparticles have a positive effect on reducing viscosity, the greatest effect was noted with 0.01% nanoparticles, this composition can be used to increase the production of high-viscosity oils. Keywords: nanotechnology; metal nanoparticles; enhanced oil recovery; reduce oil viscosity.

Efficient photo-assisted reduction of Cr(VI) via activated carbon mediated Z-scheme FeS2/α-FeOOH/C heterojunction: Focusing on molecular oxygen fate and synergetic reduction mechanism

Herein, pyrite (FeS2), goethite (α-FeOOH) and activated carbon (C) were combined to construct FeS2/α-FeOOH/C composites with C mediated Z-scheme heterojunction for efficient photo-assisted Cr(VI) reduction. Characterization tests indicated the strong interaction via Fe-O-C and C-S-C, the increased amount of crystal defects and surface oxygenic functional groups, and the decreased agglomeration degree during combination strengthened electron transport and visible light conversion efficiency, resulting in synergistic effect for enhanced Cr(VI) removal. Additionally, C mediated Z-scheme heterojunction with lower resistance facilitated the transfer and separation efficiency of photo-generated carriers, further accelerating Cr(VI) reduction. Consequently, almost 100 % of Cr(VI) was reduced via FeS2/α-FeOOH/C in 60 min, 4 times that of pristine FeS2. Quenching, EPR and control experiments confirmed photocatalysis made more contribution than single reductive reagents (FeS2) in Cr(VI) reduction. The specific contribution rate of reductive species like e−, Fe2+, S22− and •O2− in this complicated system was firstly detailedly demonstrated and •O2− played a predominant role under oxic condition. Meanwhile, oxidative species like H2O2, 1O2 and •OH ascribed to DO activation or photo-generated h+ preferred to reacted with Fe2+ and S22− with higher reducibility and-only delayed Cr(VI) reduction rate. Hence, the final total Cr(VI) removal efficiency and generated Cr(III) kept stable in oxic solution.

Glutarimidedioxime: A Complexing, Reductive, and Nitrosyl Reagent for Molybdenum.

Glutarimidedioxime is a cyclic amidoxime moiety formed during the synthesis of amidoxime-functionalized fibers and apparently facilitates the extraction of uranium from seawater. Herein, we comprehensively explore differences between molybdenum and vanadium coordinated by glutarimidedioxime. The high adsorption of vanadium is explained by the formation of rare nonoxido vanadium(V) complexes, where each bare V5+ is coordinated with two tridentate glutarimidedioxime ligands. By contrast, molybdenum is coordinated by only one glutarimidedioxime ligand, and the oxido Mo═O bonds in molybdate cannot be displaced by the ligand. Under seawater conditions, vanadium is fully complexed. Meanwhile, approximately 25% of molybdenum ions are in the form of free molybdate even if the concentration of glutarimidedioxime is 100000 times that of molybdenum. Glutarimidedioxime was expected to be more stable in the presence of metal ions than without them. However, complexation with molybdenum accelerated the degradation of the glutarimidedioxime ligand to release hydroxylamine. Molybdenum(VI) was then reduced by hydroxylamine, which itself was oxidized into nitrosyl. Vanadium heavily outcompetes adsorption of uranium, while molybdenum causes the degradation of glutarimidedioxime; the latter issue has previously been neglected and was first reported here.

(Invited) Modification of Photocatalyst Surface for Selective Conversion of CO2

Catalytic conversion of CO2 into valu-added products such as CO, HCOOH, HCHO, CH3OH, and CH4 is attracting great attentions as a promising technique for carbon neutrality. In the conventional heterogeneous catalytic processes for the CO2 conversion, it is necessary to use a reducing reagent such as H2 or hydrocarbons under high-temperature conditions. However, the photocatalytic conversion of CO2, regarded as an artificial photosynthesis, mainly use H2O as a more favorable reductant. Among many reported photocatalysts for the conversion of CO2 using H2O as a reductant, number of photocatalysts is limited to those which satisfy the following requirements: (i) origin of CO2 reduction products is confirmed using 13C isotope labeled CO2, (ii) selectivity toward the CO2 reduction products is above 50%, and (iii) stoichiometric O2 (the oxidation product of H2O) is produced. The appropriate modifications of the photocatalyst surface are significant for the improvement in the selectivity of photogenerated electrons toward CO2 reduction, because H2 evolution via reduction of protons (H+) is thermodynamically favorable as compared with CO formation via reduction of CO2. In this presentation, some of the achievements in the photocatalyst development focusing on surface modification will be presented.

Dispersibility and Morphologically Controlled Synthesis Method of Fe Metal Particles By Utilizing the Metal Complexes in an Aqueous Solution

Fe oxide based magnetic beads are widely used to recover the virus in an immunoprecipitation process. Moreover, these can also apply for using as the toxic metal ions recovery materials. To increasing these abilities, in other word, to synthesize the high-performance magnetic beads, the use of pure iron particles with a diameter of 1 µm as the core materials are effective.Thus, the development of effective and green synthesis method of Fe particles in an aqueous phase is important. However, in an aqueous phase synthesis process, Fe particles were synthesized only in acidic solution by using strong reducing reagent, such as NaBH4, while it cannot be achieved in the basic solution since iron hydroxide, which is easily formed in this condition, cannot be reduced into metal Fe. Here, former method is not suitable for commercial synthesis procedure since large amounts of Hydrogen gas generated. Therefore, synthesis method of Fe iron particles under basic condition should be developed.Until now, we tried to synthesis the various metal/alloy nanoparticles, such as Pd20Te7 nanoparticles for the catalysts and Cu-In alloy nanoparticles for the application of solar cell, by utilizing the restricted metallic complexes controlling method in an aqueous solution under room temperature. In this method, reduction potential of the metal species can be controlled under the room temperature, consequently metal/alloy nanomaterials with uniform and well crystallized structure can be successfully synthesized.In this study, we proposed the dispersibility and morphologically controlled synthesis method of Fe particles under basic conditions and using gel networks which is a safe and simple approach to suppress the synthesis of chain-type morphology.Fe complex ratio in an aqueous phase were restricted as the function of pH, complexing reagent species and/also concentration. For example, Fe complex can be restricted into single complex in the basic condition, 8<pH<11.By using this homogeneous Fe complex condition, metal Fe nanoparticles were successfully synthesized. Moreover, the addition of gel networks can effectively control the dispersibility of the synthesis Fe particles. Removing method of gel networks on the surface of the synthesized Fe particles are also developed, and finally Fe particles with the organic-free surface can be obtained.Other results will present in our presentation. This work was supported by JSPS KAKENHI Grant Number 21H03628 and DOWA holdings.[1] H. Takahashi et.,al, Applied Catalysis A: General 392 (2011) 80–85

Photocatalytic low-temperature defluorination of PFASs.

Polyfluoroalkyl and perfluoroalkyl substances (PFASs) are found in many everyday consumer products, often because of their high thermal and chemical stabilities, as well as theirhydrophobic and oleophobic properties1. However, the inert carbon-fluorine (C-F) bonds that give PFASs their properties also provide resistance to decomposition through defluorination, leading to long-term persistence in the environment, as well as in the human body, raising substantial safety and health concerns1-5. Despite recent advances in non-incineration approaches for the destruction of functionalized PFASs, processes for the recycling of perfluorocarbons (PFCs) as well as polymeric PFASs such as polytetrafluoroethylene (PTFE) are limited to methods that use either elevated temperatures or strong reducing reagents. Here we report the defluorination of PFASs with a highly twisted carbazole-cored super-photoreductant KQGZ. A series of PFASs could be defluorinated photocatalytically at 40-60 °C. PTFE gave amorphous carbon and fluoride salts as the major products. Oligomeric PFASs such as PFCs, perfluorooctane sulfonic acid (PFOS), polyfluorooctanoic acid (PFOA) and derivatives give carbonate, formate, oxalate and trifluoroacetate as the defluorinated products. This allows for the recycling of fluorine in PFASs as inorganic fluoride salt. The mechanistic investigation reveals the difference in reaction behaviour and product components for PTFE and oligomeric PFASs. This work opens a window for the low-temperature photoreductive defluorination of the 'forever chemicals' PFASs, especially for PTFE, as well as the discovery of new super-photoreductants.

An Efficient Method for the Selective Syntheses of Sodium Telluride and Symmetrical Diorganyl Tellurides and the Investigation of Reaction Pathways.

Studies on organotellurium compounds have not been extensively conducted due to a lack of tolerable synthetic methods, difficult isolation processes, and their chemical instabilities. Overcoming these hurdles, we developed an efficient and mild method for the selective synthesis of symmetrical diorganyl tellurides 1, a representative class of organotellurium compounds, using a proper reducing reagent. The reaction condition was optimized for the selective formation of 1 by forming the telluride dianion (Te2-) using a reducing reagent, sodium borohydride (NaBH4), and then followed by the addition of organyl halides. The optimized reaction condition was as follows: (1) Te (1.0 eq), NaBH4 (2.5 eq) in DMF for 1 h at 80 °C; (2) organyl halides (2.0 eq) for 3-5 h at 25-153 °C. Using this condition, 18 various diorganyl tellurides 1 were selectively and efficiently synthesized in reasonable yields (37-93%). The reaction pathways for the formation of diorganyl tellurides 1 were also investigated. Consequently, we established a practical and efficient method for the selective synthesis of diorganyl tellurides 1 as a representative class of organotellurium compounds.

Ring Expansion Reactions via C-N Bond Cleavage in the Synthesis of Medium-sized Cycles and Macrocycles

The literature review discusses and systematizes synthetic approaches to medium-sized cycles and macrocycles based on ring expansion reactions of bi- or polycyclic systems via C-N bond cleavage. Ring expansion reactions of bicyclic ammonium salts proceed via thermal decomposition or the action of strong bases. Bi- or polycyclic systems containing a common amine group can be reduced with strong reducing reagents, e.g. lithium aluminum hydride. Ammonium derivatives are much more prone to nucleophilic attack and quite often are used as starting materials for the synthesis of medium-sized cycles. Bicyclic systems containing a common aminal or amidine group are used for the synthesis of medium-sized rings and macrocycles via cleavage of the endocyclic C-N bond. Various methods of their activation and reduction are discussed in the review.

Label-free differential chemiluminescent immunosensor based on magnetic nanoparticles CuFe2O4@ABEI-GNPs with dual catalytic sites

BackgroundCancer has become one of the main causes of death globally. The level of tumor markers in serum is correlated with the occurrence of cancer. Carcinoembryonic antigen (CEA) is the most commonly utilized tumor marker for cancer detection. Recently, various analytical technologies have been reported to detect biomarkers. However, developing a simple, sensitive, and noninvasive approach for CEA detection remains challenging in cancer diagnosis. Consequently, there is an urgent need for researchers to carry out innovative approaches for CEA detection. ResultIn this work, copper ferrite nanoparticles (CuFe2O4 NPs) with excellent dispersity and fascinating magnetism have been successfully synthesized. To get CuFe2O4@ABEI-GNPs, ABEI-gold NPs (ABEI-GNPs) were generated on the surface of CuFe2O4 NPs by using N-(4-Aminobutyl)-N-ethylisoluminol (ABEI) as a mild reduction reagent to reduce chloroauric acid tetrahydrate (HAuCl4·4H2O). The CuFe2O4@ABEI-GNPs exhibited a superior chemiluminescence (CL) performance compared with CuFe2O4@ABEI NPs, which was attributed to the synergistic catalysis effects of CuFe2O4 NPs and GNPs. Interestingly, two unique CL emission peaks were observed in the kinetic curve of CuFe2O4@ABEI-GNPs. Furthermore, it was found that the kinetic curve could be regulated by the pH of hydrogen peroxide (H2O2) and a possible CL mechanism was proposed. Owing to the favorable CL properties of CuFe2O4@ABEI-GNPs, a label-free differential immunosensor was fabricated for CEA monitoring using the intensity difference between CL-1 and CL-2. The developed immunosensor exhibited a wide linear range from 0.1 to 5000 pg/mL, and a low detection limit of 0.05 pg/mL. Significance and noveltyThe immunosensor was capable of determining CEA in real samples with simple operation, high accuracy, and good sensitivity. This study introduces a novel approach for developing CL functionalized materials, which have broad application potential in bioassays. The proposed differential method could serve as a novel tool for determining CEA in the diagnosis of clinical cancer.

Formate-facilitated recovery of wastewater anammox granular sludge from oxygen inhibition: Effects and mechanisms

Oxygen leakage due to poor reactor sealing or accidental aeration can have detrimental impacts on the performance of wastewater anammox processes. Strategies of restoring functionality of anammox consortia are scarce, and providing appropriate chemical reducing reagents may help reduce oxidative damage. This study characterized the responses of anammox granular sludge (AnGS) to oxygen inhibition, and identified formate as an effective promoter capable of facilitating activity recovery, while other organics (acetate, glucose, methanol) were less effective. Upon 12 h of air exposure (DO: 1.2 ± 0.1 mg/L), the total nitrogen removal efficiency of a lab-scale AnGS reactor decreased from 85.15 % to 45.46 %. Compared with natural recovery (without chemical addition), potassium formate at 10 mg COD/L for 3 days significantly increased the total nitrogen removal efficiency, both in the short-term (66.68 % vs 57.09 %, 3 days post inhibition) and long-term (82.34 % vs 72.88 %, 30 days post inhibition). By examining sludge morphology, metagenome and transcriptome, the following potential mechanisms were proposed: 1) rapidly decreasing intracellular ROS; 2) enhancing nitrite turnover; 3) maintaining granular sludge integrity; 4) facilitating interspecies metabolic interactions. The ability of formate to facilitate sludge recovery from oxygen inhibition also implies its potential in mitigating other oxidative stresses in wastewater anammox reactors.

A Simple Conversion of Aldoximes to Nitriles Using Thiourea Dioxide

AbstractThiourea dioxide (TDO) has been demonstrated to be an efficient reagent for the transformation of aromatic, heteroaromatic, alkenyl and aliphatic aldoximes to respective nitriles in excellent yields. Furthermore, this method has been applied to the synthesis of fungicide cyazofamid from a commercial precursor using TDO as a pivotal dehydrating and reducing reagent. This new procedure offers simple and easily reproducible technique for nitrile synthesis and highlights the synthetic utility of TDO as a versatile reagent in organic chemistry.

Development of a lysosome-targeted probe for revealing the fluctuations of the intracellular hypochlorous acid (HClO) during ferroptosis

Hypochlorous acid (HClO) participates in many biological processes in live systems, and has been demonstrated to be close with ferroptosis. In situ and rapid visualization of lysosomal HClO during ferroptosis is crucial for deeply studying the biological function of HClO. Here, we constructed a lysosome-targeted probe (Lys-C) to explore the level changes of the lysosomal HClO during ferroptosis. Lys-C selected morpholine framework as lysosome-targeting unit and utilized p-aminophenylether as response site for HClO. After the reaction of Lys-C with HClO, an emissive naphthalimide-based dye was generated, accompanying by a prominent increase (∼70-fold) in the emission intensity at 562 nm. Imaging tests indicated that Lys-C could be employed to visualize lysosomal HClO in the living HeLa cells. Moreover, it was proved that erastin-induced ferroptosis could give rise to a remarkable enhancement of lysosomal HClO level, and the natural reducing reagents (e.g. DHLA, rutin and VE) could effectively stem the prominent increase of lysosomal HClO levels during ferroptosis.

Nickel Boride as Hydride Source in Nickel Catalyzed Chemoselective Reduction of α,β‐Unsaturated Amides

AbstractA facile and highly efficient chemoselective reduction of α,β‐unsaturated amides leading to saturated amide has been described. In situ generated nickel boride was found to act as an efficient reagent for the conjugate reduction. The reaction proceeds smoothly under an inert atmosphere at ambient temperature with a moderate to good yield. Both aliphatic and aromatic α,β‐unsaturated amides were found to be compatible with the reaction protocol.

Твердофазное восстановление оксидов FexOy и MnxOy углеродом в условиях низкотемпературного обжига шихты на основе марганцевых отходов

Based on complex analytical studies, including methods of atomic emission spectrometry with inductively coupled plasma and X-ray phase analysis of intermediate and final products, the material and mineralogical compositions of manganese wastes of the Dzhezdinsky GOK have been studied. It is shown that the low content of iron and manganese in waste determines the need for a preliminary operation for their enrichment. The mechanism of be havior of iron and manganese oxides under conditions of low-temperature firing of a charge composed on the basis of manganese waste has been studied. Based on thermodynamic calculations of reactions of reduction of iron and manganese oxides by carbon, the possibility of complete reduction of iron to metal from its higher and lower oxides is shown. Higher man ganese oxides are subjected to solid-phase reduction by carbon. Stable manganese oxide at the temperatures of firing to metal is practically not restored due to the positive values of the Gibbs free energy. To increase the iron content in the charge, it is necessary to provide for the addition of iron-containing waste with a high iron content to the charge, for example, rolling scale, etc. When arranging the final charge, it is necessary to take into account the optimal carbon consumption: carbon consumption should not exceed the stoichiometrically necessary amount for the reduction of iron and manganese oxides. The excess carbon not used for the reduction of MnO will remain in the charge, and will be fully used as a reducing reagent during the reduction melting. The metallized product obtained after firing must be subjected to gran ulation in order to obtain durable granular pellets, which will represent the final monoshift for the production of high-quality ferromanganese.

Edta-assisted rapid synthesis of highly monodisperse and water-soluble ZnSe quantum dots colloids by electron-beam irradiation

ZnSe quantum dots (QDs) have attracted attentions due to small size and strong fluorescence. However, ZnSe QDs are easy to agglomerate and insoluble in aqueous solutions, which limits their practical applications. Herein, we report a novel strategy for synthesizing highly dispersed and water-soluble ZnSe QDs by electron beam radiation with the aid of EDTA within only a few minutes at room temperature without any reduction reagents. In the reaction system, EDTA plays an important role in controlling the quantum size of crystal growth, inhibiting the agglomeration of ZnSe QDs and improving the water solubility. ZnSe QDs exhibit a large bandgap of 4.3 eV, significantly blue shifted compared with bulk ZnSe due to the quantum confinement effect. Constructed the structural model by MS, the nucleation reaction and growth mechanism of ZnSe QDs are proposed. Electron-beam irradiation can be widely used to synthesize water-soluble semiconductor QDs with promising application in biological imaging.

Green-synthesized Ag hierarchical assemblies for SERS detection of rhodamine dye

This study presents a simple benchtop synthetic protocol for the fabrication of silver (Ag) hierarchical structures in aqueous media using environmentally friendly and inexpensive reagents under mild experimental conditions. Natural organic acids that are known to be present in plants were employed as reducing and morphology-directing reagents. SEM and TEM imaging revealed that the products are three-dimensional hierarchical structures that were formed from self-assembly of smaller nanoparticles. They are generally spherical in shape, measure around 1.5 to 5 μm in size, and possess highly roughened surfaces due to the interstitial gaps between their nanoparticle subunits. Their hierarchical architecture allows for strong absorption of light in a broad range of wavelengths that extends to the near-infrared region. In addition, their surface morphology has an abundance of hot spot regions, which are capable of inducing strong SERS enhancement effects. The green-synthesized Ag nanostructures showed remarkable SERS activity when used as substrates for the detection of rhodamine 6G dye, a highly toxic water contaminant, even at a concentration as low as 10–8 M. Overall, this study does not only provide a greener approach to Ag hierarchical structures, but also demonstrates the immense potential of these nano-assembled architectures in the sensitive detection of organic dye pollutants.

Pd Nanoparticles Supported on Luffa Sponge as a Heterogenous Catalyst for C−O and C−C Coupling Reaction: From Waste to Use

AbstractThis work reports a practical approach for C−O and C−C bond formation reactions catalysed by Pd nanoparticles supported on Luffa sponge (PdNPs@LS).PdNPs@LS were prepared via a green route in‐situ by using ethanol as solvent, and lignin content present in the luffa sponge could work as an effective reducing reagent to reduce Pd(II) to Pd(0) without any harsh chemical used for reduction. The bio‐based support used i. e. Luffa sponge extracted from the waste feedstock of Luffa guard in a simple filtration method is a cheap, biodegradable, abundant and renewable source with netting‐like three‐dimensional porous structure. Without significant loss of its activity the PdNPs@LS could be easily recovered and recycled for at least three times. The catalyst is characterized by FT‐IR, TGA, SEM‐EDX, TEM, and XPS analyses.

A Review of the Use of the Nickel Catalyst in Azide‐Alkyne Cycloaddition Reactions

ABSTRACTTrying to find beneficial and effective catalysis for synthesizing biologically active and valuable 1,2,3‐triazoles is continually being studied to make the procedure more efficient, green, and eco‐friendly. The click reaction is famous in green chemistry for its high selectivity and efficiency in generating 1,2,3‐triazoles with important pharmaceutical and biological activities. 1,3‐Dipolar cycloaddition reaction of organic azides and alkynes by copper‐mediated have a great deal of attention paid to and developed to provide 1,2,3‐triazoles. However, utilizing Cu(II) species frequently requires a reducing reagent, making this approach less atom‐economic. Recently, notable progress has been made in designing and developing metal‐catalyzed click reactions to prepare 1,2,3‐triazoles. As appropriate alternatives to copper catalysts, nickel catalysts can be a good choice in click reactions. This review thoroughly studies the excellent potential of nickel catalysts in azide‐alkyne cycloaddition reactions and recommends using them as proper alternatives to traditional copper catalysts. This review can pave the path for further application of nickel catalysts in click reactions.

Exploring a facile preparation method for Co-Ni/MoS2-derived nanohybrid from wheat straw extract and its physicochemical properties.

This study presents a novel approach for the fabrication of a Co,Ni/MoS2-derived nanohybrid material using wheat straw extract. The facile synthesis method involves a sol-gel process, followed by calcination, showcasing the potential of agricultural waste as a sustainable reducing and chelating reagent. The as-prepared nanohybrid has been characterized using different techniques to analyse its physicochemical properties. X-ray diffraction analysis confirmed the successful synthesis of the nanohybrid material, identifying the presence of NiMoO4, CoSO4 and Mo17O47 as its components. Fourier-transform infrared spectroscopy differentiated the functional groups present in the wheat straw biomass and those in the nanohybrid material, highlighting the formation of metal-oxide and sulphide bonds. Scanning electron microscopy revealed a heterogeneous morphology with agglomerated structures and a grain size of around 70 nm in the nanohybrid. Energy-dispersive X-ray spectroscopy analysis shows the composition of elements with weight percentages of (Mo) 9.17%, (S) 6.21%, (Co) 12.48%, (Ni) 12.18% and (O) 50.46% contributing to its composition. Electrochemical analysis performed through cyclic voltammetry showcased the exceptional performance of the nanohybrid material as compared with MoS2, suggesting its possible applications for designing biosensors and related technologies. Thus, the research study presented herein underscores the efficient utilization of natural resources for the development of functional nanomaterials with promising applications in various fields. This study paves a way for manufacturing innovation along with advancement of novel synthesis method for sustainable nanomaterial for future technological developments.

The optimised method of HPLC analysis of glutathione allows to determine the degree of oxidative stress in plant cell culture

Redox regulations and antioxidant defence play a central role in the acclimation of plants to their environment. Glutathione represents an essential component of the cellular antioxidant defence system, which keeps levels of reactive oxygen species (ROS) under control. High-performance liquid chromatography (HPLC) separation with fluorescence detection is a sensitive method that enables analysis of reduced and oxidised glutathione levels in small samples of plant tissues or plant cell culture. We aimed to optimise the method to obtain more accurate information about the total level of glutathione and the proportion of the reduced form (GSH) by choosing the most suitable reduction reagent and the conditions under which the reduction occurs. The applicability of the developed method was verified by analysing tobacco cells treated with hydrogen peroxide, which caused a decrease in the GSH/total glutathione ratio. Significant changes in the level of glutathione as well as in the GSH/total glutathione ratio were also observed during tobacco cell culture development.