Diphenylamine reagent

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. 

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... 

Diphenylamine reagent 179 Diphenylboric acid-2-aminoethyl ester reagent 277... 

Nitramines dissolved in concentrated sulphuric acid give a blue colour with 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... 

E. Diphenylamine Reagent is prepd by dissolving lg of C6HS.NH.C6H5 in 100ml of coned reagent-grade sulfuric acid... 

V. Treatment with Diphenylamine Reagent. See item E under colorimetric reagents and Charts A Si B. A yel color indicates the presence of one of the expls TNT, TNAns, HNDPhA, PA, AmmPic or DNPh viol, blue or black color indicates DNT, DNB, DINA, Tetryl, PETN, RDX, EDNA, EDD or AN red color indicates o-MNN... 

Methylnitramine decomposes explosively in contact with concentrated sulfuric acid. If the substance is dissolved in water, and if concentrated sulfuric acid is added little by little until a considerable concentration is built up, then the decomposition proceeds more moderately, nitrous oxide is given off, and dimethyl ether (from the methyl alcohol first formed) remains dissolved in the sulfuric acid. The same production of nitrous oxide occurs even in the nitrometer in the presence of mercury. If methylnitramine and a small amount of phenol are dissolved together in water, and if concentrated sulfuric acid is then added little by little, a distinct yellow color shows that a trace of nitric acid has been formed. The fact that methylnitramine gives a blue color with the diphenylamine reagent shows the same thing. 

Nitroguanidine and nitrosoguanidine both give a blue color with the diphenylamine reagent, and both give the tests described below, but the difference in the physical properties of the substances is such that there is no likelihood of confusing them. 

When a large crystal of cyclonite is added to the diphenylamine reagent, a blue color appears slowly on the surface of the crystal. Powdered cyclonite gives within a few seconds a blue color which rapidly becomes more intense. If cinnamic acid is dissolved in concentrated sulfuric acid, and if finely powdered cyclonite is added while the mixture is stirred, gas comes off at a moderate rate, and the mixture, after standing over night and drowning, gives a precipitate which contains a certain amount of p-nitro-cinnamic acid. 

The diphenylamine reagent is made up according to Burton (1956). To 500 ml glacial acetic acid add 7.5 ml concentrated sulphuric acid and 7.5 g diphenylamine. Mix cautiously and store in a brown bottle at room temperature. Just before use add 0.1 ml 1.6% acetaldehyde to 20 ml of the above mixture. 

Diphenylamine reagent contains glacial acetic acid and concentrated sulfuric acid. Handle with care. Use gloves. 

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. 

Why must you handle the diphenylamine reagent with great care ... 

Can the diphenylamine reagent distinguish between ribose and deoxyribose, and between DNA and RNA ... 

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. 

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