US 4,861,989 A · Ion vapor source for mass spectrometry of liquids

Abstract

This disclosure is concerned with method and apparatus for vaporizing liquid solutions in order to detect, quantitate, and/or determine physical or chemical properties of samples present in liquid solution. Mixtures may be separated by an on-line liquid chromatographic column and the methods used for detection, quantitation, indentification, and/or determination of chemical and physical properties include mass spectrometry, photoionization, flame ionization, electron capture, optical photometry, including UV, visible, and IR regions of the spectrum, light scattering, light emission, atomic absorption, and any other technique suitable for detecting or analyzing molecules or particles in a gaseous or vacuum environment. The method and apparatus involves controlled partial vaporization of the solution. Methods are disclosed for controlling the degree of partial vaporization and the temperature at which this vaporization occurs, and for maintaining this degree of vaporization essentially constant even though the solvent flow rate and/or composition may vary in either a controlled or an uncontrolled fashion. This "thermospray" method and apparatus allows the solvent to be substantially vaporized to produce supersonic free jet containing a fraction of unvaporized solvent as liquid droplets entrained in the jet. Solutes which are less volatile than the solvent are preferentially contained in the droplets. Methods are di GOVERNMENT SUPPORT The invention described herein was made in the course of work under a grant or award from the Department of Health, Education, and Welfare.

Claims20

Dependent claims

A method of forming an ion vapor from a liquid sample, said liquid sample being passed through a capillary tube of a vaporizer and discharged therefrom as a thermospray of minute particles for analysis of vaporized ions of interest, said method comprising:

heating the capillary tube along a predetermined length thereof;
sensing the temperature of the liquid sample at a predetermined location within the vaporizer;
automatically controlling heating of the capillary tube and thereby the temperature of the liquid sample being passed therethrough in response to the sensed temperature to form a thermospray of vapor and unvaporized minute particles, the thermospray having a constant degree of partial vaporization when discharged from the capillary tube;
providing a confining chamber downstream from the capillary tube for receiving at least a portion of the thermospray discharged from the capillary tube and for limiting adiabatic expansion of the vapor discharged from the capillary tube;
and
heating the vapor within the confining chamber to vaporize substantially all the discharged minute particles within the confining chamber by contact with the heated vapor;
and
thereafter withdrawing from the confining chamber, for analysis, the vaporized ions of interest.

5 more elements

A thermospray vaporizer for obtaining an ion vapor from a liquid sample for analysis of vaporized ions of interest, the vaporizer comprising:

a capillary tube means defining a discharge nozzle at an end thereof for passing the liquid sample therethrough;
a temperature sensing means for sensing the temperature of the liquid sample at a predetermined location within the vaporizer;
first heating means for heating a predetermined length of the capillary tube means and thereby heating the liquid sample passing therethrough;
control means for regulating the first heating means in response to the temperature sensing means to partially vaporize the liquid sample within the capillary tube and to form a thermospray of vapor having ions of interest and unvaporized minute particles, the thermospray having a constant proportion of vapor to unvaporized particles when discharged from the capillary tube means;
confining means forming a chamber for receiving at least a portion of the thermospray discharged from the capillary tube means to limit adiabatic expansion of the discharged vapor;
and
second heating means for heating the vapor within the confining means to vaporize substantially all the discharged minute particles within the confining means by contact with the heated vapor.

4 more elements

Dependencies are inferred from the claim text.

Ion vapor source for mass spectrometry of liquids

Life of this patent

Ion vapor source for mass spectrometry of liquids

Life of this patent

Abstract

Claims20