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FOX Reagent
The FOX reagent, or ferrous oxidation−xylenol orange, is used to measure levels of hydrogen peroxide in biological systems. The reagent is incubated with the sample and absorbance of the product form after a series of oxidation reactions is then measured at a wavelength of 560 nm. The reagent itself is an aqueous solution of ferrous ammonium sulfate, sorbitol, sulfuric acid and xylenol orange. Use as an assay As an example for one of its uses, the FOX reagent can be an effective assay for the detections of lipid hydroperoxides (LOOHs) in plant tissues from different fruits and vegetables. The FOX assay relies on the oxidation of Fe2+ to Fe3+ in acidic conditions. After this initial oxidation, the xylenol orange within the assay is also oxidized to produce the product that has the 560 nm absorbance via colorimetric determination. The method itself is practical because of its relative cheapness and because the FOX reagent is not influenced by environmental factors, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xylenol Orange
Xylenol orange is an organic reagent, most commonly used as a tetrasodium salt as an indicator for metal titrations. When used for metal titrations, it will appear red in the titrand and become yellow once it reaches its endpoint. Historically, commercial preparations of it have been notoriously impure, sometimes consisting of as little as 20% xylenol orange, and containing large amounts of semi-xylenol orange and iminodiacetic acid Iminodiacetic acid is the organic compound with the formula HN(CH2CO2H)2, often abbreviated to IDA. A white solid, the compound is a dicarboxylic acid amine (the nitrogen atom forms a secondary amino group, not an imino group as the name suggests .... Purities as high as 90% are now available. It is fluorescent, and has excitation maximums of 440 & 570 nm and an emission maximum of 610 nm. References Analytical reagents Triarylmethane dyes Benzoxathioles Acetic acids {{Organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or " high-test peroxide", decomposes explosively when heated and has been used as a propellant in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a stabilizer in a weakly acidic solution in a dark bottle to block light. Hydrogen peroxide is found in biological systems including the human body. Enzymes that use or decompose hydrogen peroxide are classified as peroxidases. Properties The boiling poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferrous Ammonium Sulfate
Ammonium iron(II) sulfate, or Mohr's salt, is the inorganic compound with the formula (NH4)2Fe(SO4)2(H2O)6. Containing two different cations, Fe2+ and NH4+, it is classified as a double salt of ferrous sulfate and ammonium sulfate. It is a common laboratory reagent because it is readily crystallized, and crystals resist oxidation by air. Like the other ferrous sulfate salts, ferrous ammonium sulfate dissolves in water to give the aquo complex e(H2O)6sup>2+, which has octahedral molecular geometry. Its mineral form is mohrite. Structure This compound is a member of a group of double sulfates called Schönites or Tutton's salts. Tutton's salts form monoclinic crystals and have formula M2N(SO4)2.6H2O (M = various monocations). With regards to the bonding, crystals consist of octahedra e(H2O)6sup>2+ centers, which are hydrogen bonded to sulfate and ammonium. Mohr's salt is named after the German chemist Karl Friedrich Mohr, who made many important advances in the methodology o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorbitol
Sorbitol (), less commonly known as glucitol (), is a sugar alcohol with a sweet taste which the human body metabolizes slowly. It can be obtained by reduction of glucose, which changes the converted aldehyde group (−CHO) to a primary alcohol group (−CH2OH). Most sorbitol is made from potato starch, but it is also found in nature, for example in apples, pears, peaches, and prunes. It is converted to fructose by sorbitol-6-phosphate 2-dehydrogenase. Sorbitol is an isomer of mannitol, another sugar alcohol; the two differ only in the orientation of the hydroxyl group on carbon 2.Kearsley, M. W.; Deis, R. C. Sorbitol and Mannitol. In Sweeteners and Sugar Alternatives in Food Technology; Ames: Oxford, 2006; pp 249-249-261. While similar, the two sugar alcohols have very different sources in nature, melting points, and uses. As an over-the-counter drug, sorbitol is used as a laxative to treat constipation. Synthesis Sorbitol may be synthesised via a glucose reduction reaction in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogenation, C=C (and other) bonds ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorimetry
Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities. History The Duboscq colorimeter was invented by Jules Duboscq in 1870. Instruments Colorimetric equipment is similar to that used in spectrophotometry. Some related equipment is also mentioned for completeness. * A tristimulus colorimeter measures the tristimulus values of a color. * A spectroradiometer measures the absolute spectral radiance (intensity) or irradiance of a light source. * A spectrophotometer measures the spectral reflectance, transmittance, or relative irradiance of a color sample. * A ''spectrocolorimeter'' is a spectrophotometer that can ''calculate'' tristimulus values. * A densitometer measures the degree of light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5-Lipoxygenase
Arachidonate 5-lipoxygenase, also known as ALOX5, 5-lipoxygenase, 5-LOX, or 5-LO, is a non-heme iron-containing enzyme (EC 1.13.11.34) that in humans is encoded by the ''ALOX5'' gene. Arachidonate 5-lipoxygenase is a member of the lipoxygenase family of enzymes. It transforms essential fatty acids (EFA) substrates into leukotrienes as well as a wide range of other biologically active products. ALOX5 is a current target for pharmaceutical intervention in a number of diseases. Gene The ''ALOX5'' gene, which occupies 71.9 kilobase pairs (kb) on chromosome 10 (all other human lipoxygenases are clustered together on chromosome 17), is composed of 14 exons divided by 13 introns encoding the mature 78 kilodalton (kD) ALOX5 protein consisting of 673 amino acids. The gene promoter region of ALOX5 contains 8 GC boxes but lacks TATA boxes or CAT boxes and thus resembles the gene promoters of typical housekeeping genes. Five of the 8 GC boxes are arranged in tandem and are recognized by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
