Enricher for fraction of high-pressure liquid chromatography

A device is developed for concentrating a dilute solution without losing the components with boiling points slightly higher than the solvent. The device consists of an evaporator, receptor, and approximately 100 capillaries. A dilute solution is introduced into the evaporator and heated at a lower temperature than the boiling point of the solvent with the addition of a helium gas flow. As a result, mostly only the solvent evaporates, passes through the capillaries, and enters into the receptor. The low-boiling-point components in the solute, with boiling points slightly higher than the solvent, are trapped at the inlet of the capillaries. These components are then recovered by a small amount of solvent supplied from the receptor through the capillaries, with the main components of the solute concentrated at the bottom of the evaporator. A diesel fuel is separated into aliphatic and aromatic fractions by high-pressure liquid chromatography using a silica gel column. These fractions are then analyzed by low-resolution field ionization mass spectrometry, following concentration using the described device. The analytical results show that the final composition of the fractions is almost the same as that of the aliphatic or aromatic hydrocarbons in the original fuel.