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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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TL;DR: Geosmin is responsible for natural flavors in beans and beets and for off-flavors in water and fish as mentioned in this paper, and this tertiary decalol reacts with bromine in the presence of formic acid to produce a blue complex with maximum absorbance at 650 nm.
Abstract: Geosmin is responsible for natural flavors in beans and beets and for off-flavors in water and fish. This tertiary decalol reacts with bromine in the presence of formic acid to produce a blue complex with maximum absorbance at 650 nm. A method for carrying out this reaction is described, and a possible mechanism is discussed
17 citations
Patent•
19 Aug 1991
TL;DR: In this article, an absorbent collection strip has attached to a detection strip impregnated with a reagent to respectively form collection and detection regions of an integral pad, where a dermal surface is wiped with the collection region to remove a contaminant of interest therefrom and collect it on the collecting region, which is then wetted with a solvent which has a selective affinity for the contaminant.
Abstract: An absorbent collection strip has attached thereto a detection strip impregnated with a reagent to respectively form collection and detection regions of an integral pad. A dermal surface is wiped with the collection region to remove a contaminant of interest therefrom and collect it on the collection region, which is then wetted with a solvent which has a selective affinity for the contaminant. The solvent carries the contaminant or a reaction product thereof by capillary action through the collection region to the detection region where it reacts with the reagent to produce a color change which indicates the presence of the contaminant. The collection region may also be impregnated with a substance for either facilitating removal of the contaminant from the dermal surface or for cooperation with the reagent in producing the color reaction. The solvent may be either inert to the reagent or may cooperate with it in producing the color reaction. The detection region may be impregnated with plural reagents at physically spaced-apart locations, the reagents being combined by operation of the solvent to produce the color reaction.
17 citations
Patent•
14 Feb 1974TL;DR: In this article, a reagent comprising a substance which releases hydrogen peroxide in the presence of a substance available in the milk or other liquid, and another reagent which yields a color reaction, the catalase content being determined qualitatively and quantitatively with the aid of the hue of the color thus produced.
Abstract: To the milk or other catalase-containing liquid, mainly of biological origin, are added a reagent comprising a substance which releases hydrogen peroxide in the presence of a substance available in the milk or other liquid, and another reagent which, upon oxidation by hydrogen peroxide, yields a color reaction, the catalase content being determined qualitatively and quantitatively with the aid of the hue of the color thus produced. A device for carrying out this assay method comprises the two reagents separated physically from each other by a space through which the generated hydrogen peroxide can diffuse and which is capable of admitting the milk or other liquid.
17 citations
TL;DR: In this paper, a trace amount of iodate and periodate in aqueous solution was determined spectrophotometrically, based on the reaction of the ions with p-phenylenediamine, in acidic medium, to form pink-red-colored species with maximum absorption at 520 nm and adherence to Beer's law over wide concentration ranges of the ion.
17 citations
TL;DR: With the modifications described, the Acetest tablet has been found in this laboratory to be satisfactory for the routine estimation of acetoacefate in urine and an improved form of the method described by Madonia is described.
Abstract: The use of sodium nitroprussidc in a qualitative color reaction with acetoacetic acid has a history dating back to 1884, when Legal reported the development of a red color in the presence of acetoacetic acid and alkali. This color was intensified from red to purple by acidification with acetic acid soon after the alkali was added. In 1908, Rothera used neutral ammonium salts to heighten the intensity of the color reaction. He also used ammonium hydroxide instead of sodium hydroxide as the alkali. Friedemann and associates made a comprehensive review of studies of the nitroprussidc reaction. Free and colleagues described the use of the Acetest tablet, which is composed of sodium nitroprussidc, aminoacetic acid, dibasic sodium phosphate as the alkali, and lactose as a binder. The aminoacetic acid serves to intensify and stabilize the color produced. Madonia described the use of aminoacetic acid as a stabilizer and intensifier in a quantitative colorimetric analysis for acetoacetic acid in the blood, but he did not establish the optimal conditions for the reaction. Following is a description of an improved form of the method described by Madonia. With the modifications described it has been found in this laboratory to be satisfactory for the routine estimation of acetoacefate in urine.
17 citations