Abstract
The separation of each aliphatic amines was investigated by high performance liguid chromatography as their 2, 4-DNP derivatives. The derivatization was carried out as follows. A slightly excess of 2, 4-dinitrofluorobenzene and fine powder of sodium bicarbonate were added to an ethanol solution of amine in a flask equipped with a magnetic stirrer and a refluxcondenser and heated at 60°C for 1 h. After cooling, the mixture was diluted to the mark with ethanol. An aliquot of the solution (1 μl) was injected with a micro-syringe into the top of the column. A Yanagimoto LC-1100 HPLC equipped with a 254-nm UV detector was used and the separation was carried out on a silica column (LiChrospher SI-100, Merck), a gel column (Porous polymer-3011, Hitachi and Yanako-gel 5510-C) and a reversed phase column (RP-18, 5 μm, Merck), respectively. The mobile phases used were 2, 2, 4-trimethylpentane/1-butanol for the silica-column and methanol/water for both gel- and reversed column, respectively. The low aliphatic amines (C1C4) were completely separated by use of the silica column and the higher aliphatic amines were separated by use of the gel column with methanol/2, 2, 4-trimethylpentane as an eluent, and reversed phase column was used to all range of aliphatic amines with high efficiency.
