Color reagents

PHOTOMETRIC DETERMINATION OF ACIDIC IMPURITIES IN OILS AND ORGANIC LIQUIDS WITH THE USE OF THE ION PAIR OF TRINONYLOCTADECYLAMMONIUM AND BROMOTHYMOL BLUE AS THE COLORED REAGENT... 

Microanalysis of Explosives. See under Color Reactions and Color Reagents in Vol 3, C405-L to C420-L, and Addnl Refs below Addnl Refs 1) Anon, Military Explosives ,... 

For indirect immunoassay methods, the antigen (analyte) is bound to support materials and excess binding sites are blocked. Analyte and primary antibody are then added simultaneously, followed by the addition of enzyme-labeled secondary antibody and color reagent. The bound analyte (coating antigen) and free analyte (in... 

Cupric acetate solution. Dissolve 400 mg cupric acetate in 250 mL of ethanol. Dilute 25 mL of this solution to 100 mL with ethanol Color reagent solution. Mix 400 mL of ethanol with 120 mL of copper acetate solution and 100 mL of diethanolamine in a 1000-mL volumetric flask. After dissolution, adjust the volume to 1000 mL with ethanol... 

After refluxing, disconnect the trapping tube, and transfer the yellow solution into a 25-mL volumetric flask. Rinse the mbe with ethanol, and adjust the solution to volume with ethanol. Measure the absorbance of the solution at 435 nm against a blank prepared by diluting 15 mL of color reagent to 25 mL with ethanol. Determine the carbon disulflde content from a calibration curve obtained by plotting carbon disulfide concentrations of different standard solutions on the abscissa versus the absorbance on the ordinate. 

Folin O, Denis W. 1912. On phosphotungstic-phosphomolybdic compounds as color reagents. J Biol Chem 12 239-243. 

Add 2 drops of color reagent. Compare color produced with reference compounds on spot plate or other white porcelain surface. 

New coloring reagents significantly enhance the detection of the stabilizer compounds... 

Color reactions are chemical reactions that produce colored products. Identification of a compound, or more commonly a group of compounds, by color reactions is one of the oldest and simplest methods in analytical chemistry. It is based on the fact that a specific compound or a group of compounds, when treated by an appropriate reagent (often called color reagent ), produce a color that is characteristic of this compound or group of compounds. 

Color reactions are used in the laboratory in conjunction with thin-layer chromatography (TLC) — a routine and highly popular method for the analysis of explosives (for a full review, see Ref. [1, chapter 5, pp. 59—85] and Ref [2, chapter 2, pp. 33—41]). Spots on the TLC plates are visuaHzed by spraying the plates with appropriate color reagents. 

Ethylenediamine in dimethylsulfoxide solution [11] was a popular color reagent for nitroaromatic explosives in some military laboratories in the United States. 

Another non-specific color reagent for RDX and HMX is a solution of thymol in concentrated sulfuric acid [3, 56, 59]. It produces a typical red color. Positive results are also obtained with non-explosive compounds such as sugars and aldehydes. 

Another field technique for screening soils for the presence of TNT, 2,4-dinitrotoluene (2,4-DNT) and RDX was reported [99]. The color reagents were KOH for TNT (red color) and sodium sulfite for 2,4-DNT (blue-purple color). In screening soil for the presence of RDX, the first step would be to remove any potential contaminants - nitrite and nitrate ions - from the soil, using an ion exchange resin. The RDX is then reduced by zinc powder and the resulting N02 ions are detected by the Griess reaction. Detection limits were estimated to be 1 mg of TNT or RDX and 2 mg of 2,4-DNT per 1 kg of soil. 

Janovsky Test. Color reactions produced by treating aromatic nitro compds with hot" cold alcoholic NaOH or KOH and acetonic NaOH solns. A table of color reactions of some nitro compds is given in Ref 2. See Janovsky s Reagent under COLOR REACTIONS and COLOR REAGENTS in Vol 3 of Encycl, p C405-R... 

COLOR REACTIONS AND COLOR REAGENTS in Vol 3 of Encycl, pp C405-L to C420-L... 

In this chapter we describe characteristic validation procedures of the Heavy Metals Limit Test in the Japanese Pharmacopoeia (JP) [1]. Although an equivalent test is commonly listed in both the United States Pharmacopoeia and the European Pharmacopoeia, there are differences in the color reagents and conditions of sample preparation of the JP procedure. Heavy metals are defined in the JP as poisonous metallic impurities such as Pb, Bi, Cu, Cd, Sn, and Hg that form colored colloidal precipitates with sodium sulfide TS in a slightly acidic solution of pH 3 to 4. The level is expressed as the equivalent quantity of lead. 

Antibodies can be combined with enzymes and color reagents or radioactive antigens to produce quantitative testing for drugs. The ELISA or Enzyme-Linked ImmunoSorbant Assay uses antibodies generated against the Ag to be tested for covalently linked to an enzyme which can catalyze a color change reaction such as the NADH to NAD conversion (Xmax at 340 nm). When the Ag-Ab complex is formed the enzyme is activated and the color can be detected. 

Color reactions and color reagents 3 C405-C420 analytical procedures based on color reactions, a rapid method of identification of common expl compds and of expl mixtures 3C411-C417... 

Expls, color identification by see Color reactions and color reagents 3 C405-C420... 

When a test sample (comprising a single compd or its mixt with other ingredients) is treated with an appropriate reagent, a coloration is produced which is characteristic of the compd tested. The reaction, so produced, is known as a color reaction and it may serve for identification of the sample. A reagent which produces the coloration is known as a color reagent... 

Color reagents are used extensively for identification of explosives, primary materials used in their manuf, and of various ingredients in explosive, propellant and pyrotechnic compositions... 

DNB DNT are pale yel nearly insol. If a sample of ary color is only partially sol, it is usually a mixt, such as Amatol, Tridite, BkPdr, etc. Test the aqueous solns by color reagents and compare the colors with those given in Charts A B... 

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