Topic
Color reaction
About: Color reaction is a research topic. Over the lifetime, 1194 publications have been published within this topic receiving 19579 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: A sensitive and simple spectrophotometric method for the estimation of catechol and its derivatives like dopamine hydrochloride (DPH), levodopa (LDP), methyldopa (MDP) and adrenaline hydro chlorine (ADH) in both pure form and in pharmaceutical formulation, is described.
205 citations
••
TL;DR: A qualitative method by solvent works was developed to simplify and to miniaturize the analysis of the glycolate test and found it could be determined with less than 1 mg of actinomycete cells by using a smaller amount of DON reagent and ordinary polypropylene tubes.
Abstract: The glycolate test is a method to discriminate N-acyl groups of muramyl residue in peptidoglycan of bacterial cell walls by color reaction without purification of the cell walls. The glycolyl residue presents red purple color by heating with 0.02% 2,7-dihydroxynaphthalene (DON) dissolved in concentrated H2SO4. Instead of the previous column methods for quantitative analysis, a qualitative method by solvent works was developed to simplify and to miniaturize the analysis. In this method, solvents played two roles, removal of interfering materials and extraction of glycolic acid from the cell hydrolysates. Of several solvent systems tested, diethyl ether was studied in detail on such properties as the efficiency of glycolic acid extraction under several conditions, the ability of removing various interfering compounds, and the advantage on evaporation procedure of the solvent from extracts. DON reaction of the second diethyl ether extract from cell hydrolysate of “Micromonospora nigra” JCM 3328 showed a clear red purple color of a strong absorbance at 530 nm, which is the same as that of authentic glycolic acid. The solvent method was applied to 20 strains of typical actinomycete species whose acyl types have already been known (Uchida and Seino, 1997). All glycolate test positive strains showed the clear red purple color mentioned above, whereas acetyl type strains revealed no apparent color by the same procedures. Additional experiments indicated that the glycolate test could be determined with less than 1 mg of actinomycete cells by using a smaller amount of DON reagent and ordinary polypropylene tubes. The new method was discussed for advantages in the identification of actinomycetes and for possible applications to other fields.
199 citations
••
TL;DR: An accurate yet simple procedure for the determination of total cholesterol, based upon the application of a Liebermann-Burchard color reaction directly in the solvent employed for extraction of cholesterol from serum, has been described.
Abstract: An accurate yet simple procedure for the determination of total cholesterol, based upon the application of a Liebermann-Burchard color reaction directly in the solvent employed for extraction of cholesterol from serum, has been described. Extraction of cholesterol and removal of protein are accomplished by means of acetic acid and acetic anhydride. Serum water is removed by the acid-catalyzed hydrolysis of acetic anhydride. The Liebermann-Burchard color is then developed with a stable, modified reagent consisting of equal volumes of H2SO4 and acetic acid.
Excellent agreement with the technic of Schoenheimer and Sperry is obtained. Equal intensities of color are produced by equivalent concentrations of free and esterified cholesterol. Preliminary saponification of cholesterol esters is therefore not required. Color development may proceed in ordinary room lighting without loss of accuracy.
180 citations
••
TL;DR: In this paper, the kinetics of the reaction for the formation of the pink azo dye in both fresh water and sea water was studied at different acidities, temperatures, and concentrations of N -1 naphthylethylenediamine (NED).
158 citations
••
TL;DR: In this article, a maximum capacity of ca. 40μm-pH−1/ml−1 was found at pH 10.2 when [Mg2+] was 0.045m.
152 citations