US 4,902,891 A · Thermospray methods and apparatus for interfacing chromatography and mass spectrometry

Abstract

An improved thermospray vaporizer is provided for obtaining an ion vapor from a liquid sample separated by chromatography for detection or analysis by a mass spectrometer. A thermospray vaporizer comprises a capillary tube for receiving the sample, and having a jet nozzle at one end removably affixed to the capillary tube with an aperture selectively sized for a range of sample flow rates and compositions. The jet nozzle includes a generally planar sapphire insert having a cylindrical-shaped aperture of a preselected diameter. The sapphire insert is swaged into a bass holder which has a slightly larger diameter aperture than the insert. A ferrule seals between the capillary tube and an end fitting, which is welded at one end to the outer sheath of the thermospray probe and retains and end nut at the other end to secure the holder in place. The insert is thus easily replaced by removing the end nut and the brass holder with the insert. An insert with an optimum diameter aperture may thus be selected for use with the vaporizer as a function of the presumed flow rate through the vaporizer, thereby optimizing performance.

Claims19

Dependent claims

A thermospray vaporizer for obtaining an ion vapor for detection or analysis by a mass analyzer from a liquid sample having molecules of interest separated by chromatography, the vaporizer comprising:

a metal capillary tube having an internal cylindrical passageway for transmitting the liquid sample to a discharge end thereof;
a heater for partially vaporizing the liquid smaple passing through the passageway in the metal capillary tube;
a controller for controlling the temperature of the liquid sample passing through the passageway in the capillary tube to maintain a constant degree of partial vaporization of the sample molecules discharged from the capillary tube and for producing an intense thermospray jet of vaporized ions and minute particles entrained in the vaporized jet;
a jet nozzle being removably affixed to the capillary tube at the discharge end thereof and having an aperture cross-sectional area substantially less than the cross-sectional area of the passageway in the capillary tube;
and
the aperture of the jet nozzle being selectively sized as a function of sample flow rates to satisfy the relationship 50F.sup.1/2 .ltoreq.d.ltoreq.100F.sup.1/2, wherein d is the aperture diameter in microns, and F is the sample flow rate in milliliters per minute.

3 more elements

A thermospray vaporizer for obtaining an ion vapor from a liquid sample for detection or analysis by a mass analyzer, the vaporizer comprising:

capillary tube means having an internal passageway for transmitting the liquid sample to a discharge end thereof;
heating means for partially vaporizing the liquid sample passing through the passageway in the capillary tube means;
control means for controlling the temperature of the liquid sample passing through the passageway in the capillary tube means to maintain a constant degree of partial vaporization of the sample molecules discharged from the capillary tube means;
and
jet nozzle means being removably affixed to the capillary tube means at the discharge end thereof and having an aperture cross-sectional area substantially less than the cross-sectional area of the passageway in the capillary tube means, whereby an aperture area of the jet nozzle is selectively sized as a function of sample flow rates to produce a thermospray jet of approximately vaporization velocity.

2 more elements

Dependencies are inferred from the claim text.

Thermospray methods and apparatus for interfacing chromatography and mass spectrometry

Life of this patent

Thermospray methods and apparatus for interfacing chromatography and mass spectrometry

Life of this patent

Abstract

Claims19