Showing papers on "Color reaction published in 1971"

Revised assay for serum phenyl phosphatase activity using 4-amino-antipyrine.

Abstract: A modified method for the assay of serum phosphatase activity utilising disodium phenyl phosphate as substrate is described. This is based upon the reaction of free phenol with 4-amino-antipyrine and alkaline potassium ferricyanide. Study of the kinetics of the colour reaction has led to an alteration in the concentration of the reagents used; the colour is formed instantaneously and shows a very slow rate of decay. Sodium arsenate incorporated with the amino-antipyrine reagent effectively abolishes further enzyme activity and prevents the dilution of the colour inherent in earlier methods.

Investigation of the colour reaction of phenols with 4-aminoantipyrine

Abstract: The reaction of phenols with 4-aminoantipyrine and an oxidizing agent is superior to other colour reactions of phenols because of its sensitivity. It has become the most used reaction for the colorimetric determination of phenols in various materials, but many discrepancies can be found when comparing the results of various authors. Factors influencing the course of the reaction with unsubstituted phenol were investigated in detail, by photometric and chromatographic procedures. The results were applied to 40 substituted phenols, with hexacyanoferrate and peroxosulphate as oxidants. Thus the optimal conditions for a colorimetric procedure could be found. The main factors that must be taken into account involve the concentration ratio of the 4-aminoantipyrine and the oxidizing agent, their excess relative to phenol, and the proper pH range, adjusted by a buffer solution of sufficient buffering capacity. The results obtained explain the discrepancies between the results of previous authors.

Mechanism of the Color Reaction of Active Methylene Compounds with 1, 3, 5-Trinitrobenzene Derivatives. II. The Color Reaction of Acetone with 1, 3, 5-Trinitrobenzene

Abstract: The spectral behaviors of two coloring matters (I and II) were investigated, which were formed in the color reaction of acetone with TNB. An equilibrium reaction system related with I and II was proposed as shown in Chart 4. We had found that the colorations of acetone with TNB in sodium hydroxide solutions were intensified by neutralizing the reaction mixtures with sodium dihydrogen phosphate. Now, the phenomenon was successfully explained by the scheme. On the other hand, another coloring matter (III) was isolated from the reaction mixture, which clarified the cause why the final absorption intensity at 480 mμ much increased when the conversion of I to II was carried out in the presence of excessive TNB. The structure of III, a tetracyclic compound, was determined as III' as shown in Chart 5. The correlations among the three coloring matters and their roles in the color reaction were discussed.

Color Reaction Product of Urea with Diacetyl Monoxime and Glucuronolactone. II. On the Reaction of Butylurea with Diacetyl, 1-Phenyl-1, 2-propanedione, 1-Phenyl-1-hydroxyimino-2-propanone, and 1-Phenyl-2-hydroxyimino-1-propanone

Abstract: The reaction products of the color reactions of butylurea and glucuronolactone with 1-phenyl-1, 2-propanedione, two positional isomers of its monoxime and diacetyl in aqueous phosphoric acid were investigated. The results showed that all reactions, regardless of the difference in the color developing reagent employed, gave 2, 2'-dioxo-4, 5'-diimidazolylmethane (I) derivatives as main products, and that the reactions of diacetyl and its monoxime gave tetrahydroimidazo [4, 5-d] imidazole-2, 5-dione (II) derivatives as common products. All of these compounds developed visible colors in acidic media, and the colors received strong hyperchromic shifts by the duration of the keeping time at room temperature. Because every color had close relations with the colors of the respective reaction mixtures, I and II derivatives were indicated to have significant responsibilities for the colorations. In spite of the poor reproducibility of isolation, an isolation of 1, 4-dimethyl-4-acetyl-3 (or 6)-butylcarbamoylimino-1, 2-cyclohexen-6 (or 3)-one (III) from the reaction mixture of butylurea, diacetyl and glucuronolactone was also mentioned, because its responsibility for the color reaction was not excluded. The influence of glucuronolactone on the formation of the reaction products was shown to be negligible and glucuronolactone was assumed to play its role in the process of the stabilization of the color developed.

Detection of uranium by phenol

Abstract: The color reaction of uranium (VI) with phenol was applied to the detection of uranium (VI). A drop of the sample solution as added on a drop of phenol solution on a porcelain plate. Uranium gave brown to pale yellow color depending on its amount. Iron (III), cerium (IV) and molybdenum (VI) gave similar coloration, but the color by iron and cerium dissappeared by reducing them to Fe (II) and Ce (III). Phenol is thus useful as a reagent for uranium (VI) which is more specific than thiocyanate, ferrocyanide, oxine and Rhodamine B.

Mechanism of the Color Reaction of Pyruvic Acid with p-Dimethylaminobenzaldehyde. I. On the Reaction Products of Pyruvic Acid and p-Dimethylaminobenzaldehyde

Abstract: Four reaction products (I, II, III and IV) were separated in the color reaction of pyruvic acid with p-dimethylaminobenzaldehyde in an aqueous sodium hydroxide-dimethylsulfoxide solution at the reaction temperature of 40°or 60°, and their structures and roles in the colorimetric method of pyruvic acid determination previously presented were investigated. I was obtained from the reaction mixture resulted at the reaction temperature of 40°and determined as the trans form of p-dimethylaminobenzalpyruvic acid. The absorption spectral data showed that I was the sole coloring matter in the method of pyruvic acid determination. II, III and IV were produced in the reaction at 60°, and II and IV were purified as their methyl esters. They were characterized as 5-(p-dimethylaminophenyl)-isophthalic acid derivatives as shown in Chart 1, and proved not to be related to the coloration. The reaction pathways to form those products were also discussed.

A possible mechanism of the sakaguchi reaction

Abstract: in Deitch’s barium hydroxide solvent. An intense red reaction is produced in sperm heads, Panetii cell and eosinophul leukocyte granules, keratohyaiin, tricholiyalin, liairrneduila and alkali-treated hair cortex; weaker reactions are produced in keratin, collagen, muscle and resting nuclei. Alkaline benzil, 1,2-cyclohexanedione and 9,10-phenanthrenequinone treatments prevent the reaction completely, glyoxal eloes partly and nitrous acid deamination has no effect; some acylations are partially effective and in part reversible; methvlation attenuates, reversibh; aIdehyde and SH blockades are ineffective. The reaction requires 6-10 mm for full developnient; longer exposures do not increase the density. The extreme reaction pu range is from about 12.4 to about 13.6; the reaction is optimal at 13.2-13.4 (ca. 0.20.4 N Ba(OH)2). NaOH solutions require added BaC12 or SrCl2; CaC12 and MgCI2 are less effective. Arginine gives a red color in vitro, detectable to about 2.7 mg/100 ml; alike in NaOH and Ba(OH)2, red colors appear also with guanidine and protasnine; other amino acids give green to yellow colors at pH 13. Intrusion of brown into the color reaction is retarded by exclusion of air. Dehydration and mounting proce(lures are well tolerated; stains appear stable for some months at least.