Reagent

About: Reagent is a research topic. Over the lifetime, 60091 publications have been published within this topic receiving 1234928 citations. The topic is also known as: reagens.

Ferrozine---a new spectrophotometric reagent for iron

Abstract: -N=C&N-, have been known to react as bidentate ligands with certain metal ions such as ferrous, cuprous, and cobaltous, to give colored complex species (1-6). This effect was first noticed with the ferrous ion ( I ) , and since this complex of a given compound is generally of a more intense color than are those with other ions (7), the atomic configuration in question was given the trivial name of the ferroin group. During the last century, hundreds of compounds containing the ferroin group have been synthesized (7), the majority of which demonstrate the ability to form complexes with the ferrous ion. Most of these complexes are only weakly colored, are unstable under normal physical conditions, or are formed over a very narrow pH range. A few of these compounds, however, form stable, intensely colored species with the ferrous ion and are, therefore, suitable for the quantitative determination of iron (8). Examples of compounds which have found acceptance for such use are 1,lOphenanthroline (9), 4,7-diphenyl-l,lO-phenanthroline (IO), 2,2‘-bipyridine (I]), 2,6-bis(2-pyridyl)-pyridine (11). 2,4,6tris(2-pyridyl)-1,3,5-triazine (12), and phenyl 2-pyridyl ketoxime (13, 14). Many of these reagents are the product of difficult and tedious organic syntheses and, hence, are high in cost (14). Although for even the most expensive of these reagents, the cost of a single manual analysis is fairly low, when one considers automated continuous instrumental analysis, a lowcost yet highly sensitive reagent would be desirable, since the cost of maintaining such an analytical instrument with I

Chemical Redox Agents for Organometallic Chemistry

Abstract: 1. Advantages of Chemical Redox Agents 878 2. Disadvantages of Chemical Redox Agents 879 C. Potentials in Nonaqueous Solvents 879 D. Reversible vs Irreversible ET Reagents 879 E. Categorization of Reagent Strength 881 II. Oxidants 881 A. Inorganic 881 1. Metal and Metal Complex Oxidants 881 2. Main Group Oxidants 887 B. Organic 891 1. Radical Cations 891 2. Carbocations 893 3. Cyanocarbons and Related Electron-Rich Compounds 894

Spectrophotometric and turbidimetric methods for measuring proteins

Abstract: Publisher Summary The turbidity produced when protein is mixed with low concentrations of any of the common protein precipitants can be used as an index of protein concentration. The resulting turbidity is maximum after about 10 minutes and may be measured spectrophotometrically in the wavelength region of 600 m. Standardization may be effected by comparison with the turbidity produced by a suspension of a dried protein precipitate, or reference may be had to the methyl acrylate-styrene polymer. Turbidimetric techniques are rapid and convenient, but they yield different values with different proteins. They do not permit differentiation between protein and acid-insoluble compounds such as nucleic acids. Protein estimation with the Folin-Ciocalteu reagent include (1) biuret reaction of protein with copper ion in alkali, and (2) reduction of the phosphomolybdic-phosphotungstic reagent by the tyrosine and tryptophan present in the treated protein. Protein estimation by ultraviolet absorption takes advantage of the fact that nucleic acid, however, absorbs much more strongly at 260 mμ than at 280 mμ, whereas with protein the reverse is true. This advantage is used to eliminate, by calculation, the interference of nucleic acids in the estimation of protein.

Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide.

Abstract: In this direct colorimetric procedure, serum triglycerides are hydrolyzed by lipase, and the released glycerol is assayed in a reaction catalyzed by glycerol kinase and L-alpha-glycerol-phosphate oxidase in a system that generates hydrogen peroxide. The hydrogen peroxide is monitored in the presence of horseradish peroxidase with 3,5-dichloro-2-hydroxybenzenesulfonic acid/4-aminophenazone as the chromogenic system. The high absorbance of this chromogen system at 510 nm affords useful results with a sample/reagent volume ratio as low as 1:150, and a blank sample measurement is not needed. A single, stable working reagent is used; the reaction is complete in 15 min at room temperature. The standard curve is linear for triglyceride concentrations as great as 13.6 mmol/L. Average analytical recovery of triglycerides in human sera is 100.1%, and within-run and between-run precision studies showed CVs of less than or equal to 1.6 and less than or equal to 3.0%, respectively. The method is suitable for automation.