Combination of capillary supercritical fluid chromatography and mass spectrometry with a vacuum nebulizing interface.

Abstract

A combination system of capillary supercritical fluid chromatography (SFC) with a use of CO₂ as a mobile phase and mass spectometry (MS) was developed by using a vacuum nebulizing interface. Application of the vacuum nebulizing interface enabled the operation of the SFC/MS system at a high pressure up to ca. 400 kg/cm² attained by SFC pump. By adjusting the flow rate of the nebulizing gas, vacuum of the mass spectrometer was easily controlled for chemical ionization condition. In addition, the use of isobutane as a nebulizing gas enabled stable and continuous introduction of the sample into the ion source to attain soft ionization. Analytical conditions of this SFC/MS system were epitomized for caffeine as a test sample. The system was also applied to the analysis of polyethylene glycol-400.