Topic
Color reaction
About: Color reaction is a research topic. Over the lifetime, 1194 publications have been published within this topic receiving 19579 citations.
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TL;DR: In this paper, a spectrophotometric study of the reaction of uranyl acetate and resorcinol shows that an orange-red coloured resorbinolate of composition 1:2 is formed.
8 citations
TL;DR: An automated method for the determination of acid proteinase activity has been developed with high sensitivity, precision and speed and offers great advantages in its flexibility of selecting substrate and buffer independently of the conditions for the colour reaction.
Abstract: An automated method for the determination of acid proteinase activity has been developed. The enzyme is incubated with a haemoglobin substrate after which the reaction solution is dialysed. The concentration of the liberated amino acids and peptides is determined by reaction with a trinitrobenzenesulphonic acid reagent. The technical parameters of the process and the general analytical conditions have been optimised. The method offers great advantages in its flexibility of selecting substrate and buffer independently of the conditions for the colour reaction. The final result is an automated method with high sensitivity, precision and speed. The sensitivity of the colour reaction is 1 mg l–1 of nitrogen from leucine.
8 citations
TL;DR: An improved spectrophotometric method for phosphorus determination in oils is proposed in this article, which has made significant improvements in safety, sensitivity, and efficiency in comparison with the current American Oil Chemists’ Society (AOCS) Official Method (Ca 12-55, corrected 1992).
Abstract: An improved spectrophotometric method for phosphorus determination in oils is proposed. The proposed new method has made significant improvements in safety, sensitivity, and efficiency in comparison with the current American Oil Chemists’ Society (AOCS) Official Method (Ca 12–55, corrected 1992). The AOCS method employs hydrazine sulfate as the reducing agent to generate molybdenum blue. Hydrazine sulfate is a known carcinogen in laboratory animals and a suspected human carcinogen. The chemical also irritates skin and mucous membranes. In the improved method ascorbic acid is used as the reducing agent. Ascorbic acid is equally effective as hydrazine sulfate for the color reaction. The improved method is approximately 75 times more sensitive than the AOCS method. The sensitivity is improved by measuring absorbance at the absorption peak, 825 nm, and reducing the final volume of reaction mixture for color reaction. The AOCS method determines phosphorus by measuring absorbance at 650 nm, which is about 40% of that at the absorption peak. The efficiency of this improved method is also significantly increased by reducing sample size and the volumes of sample preparation. Therefore, the improved method is more cost-effective than the AOCS method because less chemical reagents and smaller glassware are used, and the hazardous chemical waste disposal cost is eliminated. The improved method also avoids concentrated HCl and 50% KOH for sample preparation.
8 citations
Patent•
16 Aug 1985
TL;DR: A bacterium (e.g., Streptomyces sioyaensis subsp. tanegashimaensis No.9979) capable of producing FR-900336 substance is inoculated into a medium and cultivated aerobically at 20-40 deg.C for 50-100hr as discussed by the authors.
Abstract: NEW MATERIAL:FR-900336 Substance having the following physical and chemical properties. Shape and color: light yellow and needle-like crystal. Color reaction: positive in Dragendorff's reaction. Solubility: soluble in chloroform, acetone, ethyl acetate, and methanol, slightly soluble in ethanol, and insoluble in water. Melting point: browning gradually from 214 deg.C. Specific rotatory power: [alpha]D = 365 deg.(C=0.1, CHCl3). Ultraviolet absorption spectrum: table-1. Infrared absorption spectrum: table-2, etc. USE:A drug having an antibacterial action on Staphylococcus aureus, Bacillus subtilis, etc. PREPARATION:A bacterium (e.g., Streptomyces sioyaensis subsp. tanegashimaensis No.9979) belonging to the genus Streptomyces, capable of producing FR- 900336 substance, separated from soil of Tanegashima Island in Kagoshima Prefecture is inoculated into a medium and cultivated aerobically at 20-40 deg.C for 50-100hr.
8 citations