Color reaction

About: Color reaction is a research topic. Over the lifetime, 1194 publications have been published within this topic receiving 19579 citations.

[On the colour reaction of hydroxyproline with 4-dimethylaminobenzaldehyde (author's transl)]

Abstract: With the as yet unexplained chloramine-T-oxydation of hydroxyproline the formation of pyrrole-2-carboxylic acid and pyrrole could be established. On the oxydation with peroxyde as well as with chloramine-T pyrrole is the starting base for the colour reaction with Ehrlichs reagent. From a comparison of thin layer chromatographic und UV-VIS data of the dyes formed by the oxidation of hydroxyproline and the pyrrole colour reaction the formation of a dipyrrylphenylmethene salt and ms-tetra-(4-dimethylaminophenyl)-porphin is made probable.

Color Reaction of Aromatic Aldehyde with Serum Protein and Its Application to the Determination of Serum Total Globulin Concentration

Abstract: The reaction of four aromatic aldehydes including p-dimethylaminobenzaldehyde (p-DMABA) with serum protein has been studied. The aromatic aldehydes gradually reacted with serum globulin with the irradiation of a fluorescent lamp at room temperature to form a colored product with an absorption maximum at about 520 to 635 nm with high molar absorptivity, while only slightly reacting with serum albumin. The reaction rate increased as the intensity of light increased, and at about 3000 luxes the reaction completed within 45 min after the reaction started. Of the four aromatic aldehydes evaluated, the colored product of p-DMABA indicated the most excellent spectral characteristics. Based on these results, this aromatic aldehyde was applied to the detemination of the serum total globulin concentration. The measurement values by the proposed method, using a γ-globulin solution as a standard material, correlated well with those by the method of Goldenberg and Drewes using glyoxylic acid (r = 0.983), the combined biuret-BCG method (r = 0.949) and moderately with the combined biuret-cellulose acetate electrophoresis method (r = 0.899).

Improved efficiency for colorimetric determination of furfural in citrus juices

Abstract: The operational efficiency of a method for colorimetric determination of furfural in citrus juices is improved by inclusion of a concentration-screening step prior to the color reaction. The absorbance at 277 nm may be used to determine the appropriate dilution for samples exceeding the recommended maximum furfural concentration in the reaction mixture. As much as 1 h per sample may be saved in the time required for analysis.