Oxidation and Reduction Reactions

Oxidation and Reduction Reactions deals with chemical reactions involving electron transfer. It begins with oxidation numbers and their applications in naming complex molecular or ionic compounds. Rules for assigning oxidation numbers and how to calculate the oxidation number of any atom in a compound or ion are described. Extensive coverage is given to oxidizing and reducing agents, including how to identify them in a given process. Half-cell reactions are defined. Balancing redox equations with the oxidation number method and the half-reaction method are emphasized. The chapter concludes with an overview of oxidation-reduction titration and calculations based on redox titration analysis.

The Synechocystis sp. PCC 6803 open reading frame slr0201 that is homologous to sdhC from Archaea codes for a [2Fe-2S] protein

A hypothetical protein encoded by Synechocystis sp. PCC 6803 open reading frame slr0201 shows high sequence similarity to the C subunit of a group of unusual succinate dehydrogenases found in some archaeal species. Slr0201 was originally annotated as HdrB, the B subunit of heterodisulfide reductase, but appears to be SdhC instead. This protein was overexpressed in E. coli by cloning the PCR-derived slr0201 open reading frame into a pET16b-based expression vector. The overproduced Slr0201 accumulated predominantly in inclusion bodies with an apparent molecular mass of 33 kDa. The protein contained at least one [2Fe-2S] cluster based on UV-visible absorbance and CD spectra and EPR spectroscopy, in conjunction with stoichiometric analysis of protein-bound iron and sulfur content. Redox titration showed a midpoint potential (Em) of + 17 mV at pH 7.0, which is consistent with Slr0201 serving a role in transferring electrons between succinate and plastoquinone. Slr0201 was also overproduced in Synechocystis sp. PCC 6803 by introducing an additional, His-tagged slr0201 into the Synechocystis genome replacing psbA3, creating the slr0201+-His overexpression strain. Immunoblot analysis shows that Slr0201 is membrane-associated in the wild type. However, in the Slr0201+-His strain, immunoreaction occurred in both the membrane and soluble fractions, possibly as a consequence of processing near the N-terminus. The results obtained with Slr0201 are discussed in the light of one of the cyanobacterial SdhB subunits, which shares redox commonalities with archaeal SdhB.

Development of a complex of detergents for membrane units in the dairy industry

Aim. Development of a complex of detergents (acidic, alkaline, enzymatic, chlorine-containing, surfactant-containing additives) for membrane units used in the dairy industry. Materials and Methods. Methods for controlling the concentration of active substances in concentrates of agents are given on the example of KATELON 202 - determination of total acidity by the method of acid-base potentiometric titration (in terms of HNO3) and KATELON 114 – determination of the mass fraction of active chlorine by redox titration. Results. A complex of detergents for membrane plants (ultrafiltration (UV, UF), microfiltration (MF, MF), nanofiltration (NF, NF), reverse osmosis (RO, RO)), used in the dairy industry and including alkaline non-foaming, medium-, low-foam products KATELON 109, KATELON 110, KATELON 115; alkaline chlorine-containing non-foamy agent KATELON 114; acid non-foamy KATELON 202, KATELON 207, KATELON 208; high-foam neutral additives KATELON 308 and KATELON 309 – enhancers of the washing effect for KATELON 109, KATELON 110, KATELON 115; preservative non-foaming additive KATELON 310 for protection from microbiological contamination; enzyme medium supplement KATELON 601. The composition of all products, their brief characteristics and physicochemical indicators, as well as an approximate program of washing with a complex of developed preparations are given. The dependences of pH and electrical conductivity were obtained for KATELON 109, KATELON 110, KATELON 115, KATELON 202, KATELON 207, KATELON 208. Conclusion. The complex of detergents is successfully used at Kopylsky Butter Cheese Plant, Lyubansky Cheese Making Plant, Minsk Dairy Plant No. 1, Verkhnedvinsky Butter and Cheese Plant, Molodechno Dairy Plant, Volozhin production site of Minsk Dairy Plant No. 1, Tolochin Branch of Lepel Dairy Canning Plant.

Comparison of Three Independent Methods of Ampicillin Detection Using Hydrogen Peroxymonosulfate

Three unified procedures have been developed. The possibility of quantitative determination using the methods of kinetiс spectrophotometry, voltammetry, and redox titration of ampicillin (Amp) as a pure substance and in a drug using potassium hydrogen peroxomonosulfate (KHSO5) as an analytical reagent has been shown.

Degradation of Nonylphenol Ethoxylate-10 (NPE-10) by Mediated Electrochemical Oxidation (MEO) Technology

Nonylphenol ethoxylate (NPE-10) is a non-ionic surfactant that is synthesized from alkylphenol ethoxylate. The accumulation of NPE-10 in wastewater will endanger the ecosystem as well as the human being. Nowadays, NPE-10 can be degraded indirectly by using an electrochemical treatment by the advancement of technology. Thus, this study is aimed to evaluate the electro-degradation potential of NPE-10 by MEO using Ce(IV) ionic mediator. In addition, the influence of Ag(I) ionic catalyst in the performance of MEO for the degradation of NPE-10 was also observed. The potency of MEO technology in the NPE-10 degradation was evaluated by voltammetry technique and confirmed by titrimetry and LC-MS analysis. The results showed that in the absence of Ag(I) ionic catalyst, the degradation of NPE-10 by MEO was 85.93%. Furthermore, when the Ag(I) ionic catalyst was applied, the performance of MEO in degradation of NPE-10 was improved to 95.12%. The back titration using Ba(OH)2 confirmed the formation of CO2 by 46.79%, whereas the redox titration shows the total of degradation organic compounds by 42.50%. It was emphasized by the formation of two new peaks in the LC-MS chromatogram. In summary, our results confirmed the potential of MEO technology for the NPE-10 degradation.

Evaluation of ascorbic acid levels and other biochemical parameters levels in Local and Imported Lemon Juices.

Lemon fruit is an important type of Rutaceae family, it has many health benefits due to its important contents. Ascorbic acid (Vitamin C) is a water-soluble vitamin which has reductive properties, so it is used on a large scale as antioxidant in food and drinks. The goal of this search is to determine the concentrations of vitamin C and protein and minerals (Iron, Magnesium, Potassium , and Calcium) in local and imported lemon juices.Local and imported (from Turkey) lemon were chosen in this study, Ascorbic acid concentration was measured via redox titration method; involve titration with an oxidant solution: dichlorophenol indophenol. Furthermore protein concentration was measured spectrophotometry depending on Biuret method and the minerals by Atomic Absorption Spectrophotometer. The results indicated that local lemon juice is a rich source of vitamin C (24.02±1.07mg/100ml juice) in comparison to the imported lemon. However the local lemon juice gave a lowest concentration of protein (0.37± 0.21mg/100ml juice). Minerals concentrations were somewhat close when compared between the three studied groups while the pH value was slightly higher in local lemon . Our results indicates that local lemon juice is a highest source of the important antioxidant vitamin (vitamin C) with acceptable acidity .

Quantitative Determination of Vitamin C Concentration of Common Edible Food Sources by Redox Titration Using Iodine Solution

Vitamin C is isolated in 1928 and associated with hemorrhagic disease scurvy. Vitamin C is crucial for the development and maintenance of connective tissues in humans. It plays an important role in maintaining healthy gums, helps in wound healing, bone formation, relief from a common cold, and several metabolic functions. It is an antioxidant that safeguards the cells from free radical damage. It is used as a curative agent in many diseases and disorders. This research article attempts to find different concentrations of vitamin C in common edible foodstuffs. The iodine redox titration method is used for vitamin C quantity evaluation. This study is based on the vitamin C quantity of 27 common edible food sources, including lemon (Citrus limon), lime (Citrus aurantiifolia), navel orange (Citrus sinensis), grapevine (Vitis vinifera), fox grape (Vitis labrusca), pomegranate (Punica granatum), apple (Malus domestica), kiwifruit (Actinidia deliciosa), Indian tamarind (Tamarindus indica), holy basil (Ocimum tenuiflorum), coriander (Coriandrum sativum), tomato (Solanum lycopersicum), carrot (Daucus carota), radish (Raphanus sativus), bitter gourd (Momordica charantia), garlic (Allium sativum), onion (Allium cepa), potato (Solanum tuberosum), aubergine (Solanum melongena), bell pepper (Capsicum annuum), pea (Pisum sativum), common bean (Phaseolus vulgaris), pumpkin (Cucurbita moschata), pawpaw (Carica papaya), cucumber (Cucumis sativus), cabbage (Brassica oleracea var. capitata), and cauliflower (Brassica oleracea var. botrytis), are evaluated. The highest quantity of vitamin C present in Indian tamarind, i.e., 89.44 mg/100 g. This study is intended to use new vitamin C sources for nourishment.