Aniline-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. 

Aniline — Diphenylamine — Phosphoric Acid Reagent Reaction (according to [16])... 

To detect glycosides heat the chromatograms to 130—150°C for 15 min. Blue-grey zones are produced (detection limit prunasin 0.3—0.5 pg [18]). Flavonoids are better detected with a modified reagent of the following composition phosphoric acid (85%) — acetic acid — aniline — diphenylamine (20 ml - -100 ml + 5 ml + 5 g). 

Bailey, R.W. and Bourne, E.J., Color reactions given by sugars and diphenylamine-aniline spray reagents on paper chromatograms, J. Chromatogr., 4, 206, 1960 Chem. Abs., 55, 4251c, 1961. 

Colour Reactions Given by Sugars and Diphenylamine-Aniline Spray Reagents on Paper Chromatograms, R. W. Bailey and E. J. Bourne, J. Chromatogr., 4, 206-213 (1960). 

Diphenylamine—Phosphoric Acid Reagent), these condense with aniline to Schiff s... 

In the phenylation reaction of substituted anilines, the electronic nature of the substituents plays a role only on the reaction rate, not on the overall yield (4-methoxyphenyl 91% after 15 minutes and 4-nitrophenyl 90% after 16 hours). The steric hindrance is also a factor which influences the reaction in slowing down the reaction rate. To obtain good to excellent yields, an excess of bismuth reagent is then required with hindered substrates. For example, mesitylamine required 2.2 equivalents of triphenylbismuth diacetate to afford the AT-phenyl derivative in 92% after 24 hours. Moreover, triphenylamine was obtained in 23% yield after 48 hours by arylation of, iV-diphenylamine. A variety of aliphatic, alicyclic, heterocyclic and aromatic amines as well as hydrazines were N-arylated by this system. No reaction took place with a-amino acids but their esters were mono-iV-phenylated under... 

Derivatization reagent Thymol-sulfuric add Diphenylamine-aniline-phosphoric acid... 

Oxalic acid Solid diphenylamine In a test tube evaporate sample to dryness and melt with reagent over a flame. After cooling add ethanol Blue color Aniline blue formation 5... 

Pukl and Prosek (1990) used TLC-densitometry to quantify glucose, fructose, and saccharose single or multiple developments were used with a solvent system consisting of acetonitrile-methanol-pH 5.5 phosphate buffer (85 5 15) sugars were detected with a diphenylamine-aniline reagent and scanning was at 440 and 515 nm. Fell (1990) used TLC-densitometry to quantify trehalose, glucose, and fructose at 125-2000 ng-levels in less than 1 pi samples of insect hemolymph. 

Diphenylamine/aniline reagent gives a pink or purple color to a sucrose monoester where the fructose moiety is unesterified, or a blue color when the glucose moiety is unes-terified (67). Another clue to the identity of individual isomers can be gained by reacting with invertase. This enzyme only catalyzes the hydrolysis of sucrose if the fructose moiety is unsubstituted. Thus, TLC before and after invertase treatment will indicate whether the acyl group is on the fructose or glucose portion of the molecule (67). 

---