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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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Journal ArticleDOI
TL;DR: In this paper, a stoichiometric redox reaction between aliphatic thiol and a copper(II) complex with 1, 10-phenanthroline in dimethyl sulfoxide to form an intensely colored copper(I) complex had a molar absorptivity of 7000dm3 mol-1 cm-1 at 444nm.
Abstract: A novel spectrophotometric method was developed for the determination of aliphatic thiols. The method was based on the stoichiometric redox reaction between aliphatic thiol and a copper(II) complex with 1, 10-phenanthroline in dimethyl sulfoxide to form an intensely colored copper(I) complex, which had a molar absorptivity of 7000dm3 mol-1 cm-1 at 444nm. The calibration curves for five aliphatic thiols of carbon numbers 1-8 had the same slope over the range from the detection limit of 5.0×10-6 to 1.5×10-4mol dm-3. The relative standard deviation of five successive experiments was 2.0% at 8.6×10-5mol dm-3 of 1-butanethiol. The method was applied to the determination of methanethiol in gas samples.

2 citations

Journal ArticleDOI
TL;DR: The role of the ester has not been interpreted yet; however, it is so unique that it can be performed only by dimethyl oxalate, not by the other esters as discussed by the authors.
Abstract: The coloration of microamounts of boric acid with an ethanolic solution takes place in the presence of oxalic, but not in that of other acids Near-ultraviolet, visible, and infrared absorption spectroscopic studies have revealed that the aging reaction of an ethanolic curcumin-oxalic acid reagent solution is simply the esterification of the oxalic acid with the solvent used The resulting diethyl oxalate is necessary to the color reaction The role of the ester has not been interpreted yet; however, it is so unique that it can be performed only by dimethyl oxalate, not by the other esters The esterification of oxalic acid in an acetonic reagent solution may be attributed to the presence of alcoholic impurities present in aceton used The composition of the colored reaction product, rubrocurcumin, presented by Spicer and Strickland has not been substantiated yet in relation to the necessity of the esters to the color reaction

2 citations

Journal ArticleDOI
TL;DR: In this paper, a new and very sensitive and selective chromogenic reagent, 2-methylthiophenyldiazoaminoa-zobenzene (MTDAA), was synthesized and studied in detail for the determination of trace mercury(II) in water samples.
Abstract: A new and very sensitive and selective chromogenic reagent, 2-methylthiophenyldiazoaminoa-zobenzene (MTDAA), was synthesized and studied in detail for the determination of trace mercury(II) in water samples. The method is based on the color reaction between MTDAA and mercury(II). It was found that mercury(II) reacts with MTDAA in Na2B4O7-NaOH buffer solution (pH = 10.0) to form 1 : 2 red complexes; these show maximum absorption at 520 nm. Beer’s law is obeyed in 0–15 µg of mercury(II) in 25 mL of solution. The apparent molar absorptivity of the complex is 1.33 × 105 L/(mol cm); its limit of quantification, limit of detection, and relative standard deviation are 0.75 ng/mL, 0.27 ng/mL, and 1.0%, respectively, giving better sensitivity. The influence of the reaction variables and the effect of interfering ions are reported; most of the metal ions in water samples can be tolerated in considerable amounts. Only a few ions can interfere with the determination of trace mercury(II), but these can be eliminated by prior extraction. The proposed method is sensitive, simple, and rapid. It has been applied to the determination of trace mercury(II) in water samples with satisfactory results.

2 citations

Patent
03 Apr 1990
TL;DR: A polysaccharide having the following chemical and physical properties is described in this article : the ratio of saccharide: glucose, galactose, glucuronic acid, ribulic acid and acetic acid = 5:1:1.1.
Abstract: NEW MATERIAL:A polysaccharide having the following chemical and physical properties. Constitution ratio of saccharide: glucose, galactose, glucuronic acid, ribulic acid and acetic acid as main constituent components and the ratio of glucose: galactose: glucuronic acid: ribulic: acetic acid = 5:1:1:1:1-2. Elemental analysis (%): C 36.03+ or -1, H 5.00+ or -0.5, N 0.09+ or -0.05. Specific rotatory power: [alpha]=-5+ or -2 deg. (n=1, water). Solubility: soluble in water, insoluble in methanol, ethanol, isopropanol, acetone, etc. Color and properties: white cotton-like or fibrous state. Molecular weight: 345,000 (by precipitation equilibrium method). Precipitation constant: 3.3-3.5S (by precipitation rate method): Color reaction: positive in anthrone reaction and negative in carbazole reaction. USE:A gelatinizing agent and a film-forming agent. PREPARATION:A bacterium such as Rhizobium meliloti IFO 13336 belonging to the genus Rhizobium is cultivated in a nutritive medium.

2 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20227
20214
20206
20198
20186
20175