Direct heated interface probe for capillary supercritical fluid chromatography/double focusing mass spectrometry

Abstract

A capillary supercritical fluid chromatograph was coupled to a double focusing mass spectrometer with a direct heated probe Interface. The Interface contained a fused silica transfer capillary containing a frit restrictor at the end which was heated to a temperature of 300-350 °C by resistance heating. The total column effluent was transferred Into the mass spectrometer Ion source. This Interface not only preserved the chromatographic efficiency but also provided for mass spectral detection and Identification of various high molecular weight, thermally labile, and polar compounds. Electron-Impact and chemical Ionization mass spectra of selected natural products and pharmaceuticals were obtained at the low nanogram level.

Guidelines for successful SFC/MS

“…Interfaces. Typically, mobile-phase flow rates in open-tubular SFC are such that the entire effluent may be directly introduced into the ion source of a modern mass spectrometer designed for GC/ MS, resulting in a DFI interface (4,16,17). This simple interface consists of a stem that houses the chromatographic column or a transfer line that is held at the same temperature as the chromatographic oven.…”

Applications of Supercritical Fluids in Industrial Analysis

“…To enable a large portion of a packed column eluent to be handled by the mass spectrometer, a thermospray interface has been modified . Sector instruments offer the advantage of higher resolution, with interfaces of slightly different designs (Kalinoski et al, 1987;Huang et al, 1988;Reinhold et al, 1988;Kallio et al, 1989;Huang and Morgan, 1990). Chemical ionization has been reported to result in sensitivities at least one order of magnitude better than electron impact .…”

Application of capillary supercritical fluid chromatography–double focusing mass spectrometry under negative ion chemical ionization conditions

“…Details of the capillary SFC and MS equipment used in this study have been described previously (4,12). A Finnigan MAT model 8430 double-focusing mass spectrometer (San Jose, Califomia, USA) equipped with a dual EI-CI ion source, was coupled with a Lee Scientific model 501 supercritical fluid chromatograph (Salt Lake City, Utah, USA).…”

“…Flow reshction was accomplished using a frit restrictor. Details of the capillary SFC-MS interface probe can be found elsewhere (12).…”