Diphenylamine reagent for

In the derivatization of sugars with aniline-diphenylamine reagent for example, this leads to unsatisfactory irregular coloration. The standard deviation for the method deteriorates from 2 to 3% to 5 to 8%. For this reason color reactions should be avoided for direct quantitation if it is possible to scan in the UV range without derivatization. 

Qualitatively, the presence of the nonulosaminic acids is best indicated by the brilliant-red coloration formed on addition of an acidic solution of p-dimethylaminobenzaldehyde (the so-called direct Ehrlich reaction ), and by the bright-purple coloration which develops upon boiling with Bial s reagent for several minutes at 100°. In addition, the nonulosaminic acids give a blue-violet coloration with Dische s diphenylamine reagent for deoxypentoses and a positive reaction in the tryptophan-perchloric acid test. Since no single one of these color reactions is absolutely specific for a nonulosaminic acid, it is advisable to carry out at least two of these for a qualitative analysis. For quantitative determinations, all four reactions have been employed, using either A/ -acetylneuraminic acid (m. p., 183-185° [a] —32.0°) or methoxyneuraminic acid [m. p., 200° (dec.) [a]o —55.0°] as colorimetric standards. 

Diphenylamine (reagent for rayon). Dissolve 0.2 g in 100 mL of concentrated sulfuric acid. 

Thus, the dermal nitrate test is a color test for unbumed or partially burned gunpowder, ie, nitrocompds, which form a blue product with the acidic diphenylamine reagent... 

Analyses of glucose and fructose in musts of commercially processed fruit have been made for several years (18). Glucose oxidase (Worthington Glucostat reagent) has been the method of choice for glucose analysis. Acid diphenylamine reagent (24), which is specific for the keto... 

Add 5 mL diphenylamine reagent to each test tube. Mix the contents of the test tubes. Heat the test tubes in boiling water bath for 10 min. Record the color on your Report Sheet. 

With Dische s reagent for 2-desoxy sugars (diphenylamine in acetic acid and sulfuric acid) triacetyl-D-glucal and a series of other glycals and glycal derivatives give the same or a similar color as the 2-desoxy sugars.25-28... 

Diphenylamine is sparingly soluble in water, but is readily soluble in alcohol and acids. It may be used as reagent for nitric acid and nitrates. Its use as a Stabilizer is particularly important. 

Raney nickel was recommended as a convenient reagent for desulfurization of phenothiazine, and it has been used in many structural investigations. More recently, the method has been applied to various phenothiazines, - in its classical form, that is Raney nickel and hydrogen, as well as in some modified variants. Thus, working with a special Raney nickel, without hydrogen, 1,3,7,9-tetrachlorophenothiazine was desulfurized without dehalogenation the usual procedure leads, for example, to diphenylamine, when applied to 3,7-dichlorophenothiazine. ... 

Diphenylamine, (C6H5)2NH, is an example of a purely aromatic amine. The method used in its preparation has been discussed under secondary amines (491). Diphenylamine has an agreeable odor, melts at 54°, and boils at 310°. It serves as a reagent for the detection of traces of nitric acid and other oxidizing substances. When a solution of the amine in concentrated sulphuric acid is treated with a trace of nitric acid, a deep blue color is developed. 

Diphenylamine is used in the mannfacture of dyes, as a stabilizer for nitrocellulose explosives, and as an analytical reagent for colorimetric tests for nitrate and chlorate. 

Fig. 140. Thin-layer chromatogram of sphingolipids [210]. Adsorbent silica gel G solvent chloroform-methanol-water (60 + 35 + 8) time of run 2 h spray reagents diphenylamine solution and Dragendorff reagent for detection of sphingomyelin amounts 50—100 jxg of each 2 sphingolipid mixture from beef brain 2 non-esterified cerebrosides 3 cerebroside sulphates 4 sphingomyelin 5 gang-...

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