JPS63252244A - Method and device for introducing effluent to mass spectrophotometer and other gaseous phase or particle detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for introducing an effluent into a mass spectrophotometer or other gas phase or particle detector.

BACKGROUND OF THE INVENTION Suitable liquid sample introduction to gas phase or particle detectors depends on the interface between the liquid stream and the detector. The coexistence of continuous liquid sample introduction and normal operating requirements for gas phase detectors creates compatibility issues. Difficulties often arise in accommodating material flow from the liquid stream into the detector. Roughly speaking, during the evaporation process prior to gas phase detection,
Decomposition of thermolabile sample components may occur. For example, in the case of gas phase detectors, such as mass spectrophotometers, where detection is performed under reduced pressure, vacuum locking and pumping are requirements to be considered. General requirements for the interface between the liquid stream and the gas phase detector are: (1) the sample must be evaporated before detection; (2) there should be minimal thermal decomposition during the sample evaporation process. (3) The sample transport efficiency must be high enough to adhere to sufficient sensitivity:
(4) normal operating conditions of the detector must be maintained during sample introduction; (5) the composition of the sample must be maintained (eg, minimum chromatographic bandwidth) while being transported to the interface.

The success rate of interfacing a liquid stream to a gas phase detector depends on how well the above requirements are met.

The main application of the device according to the invention for gas phase detection of liquid streams is the introduction of the effluent from a liquid chromatograph into a mass spectrophotometer. Liquid chromatography (
The interface between LC) and mass spectrophotometry (MS) is called LC-MS. Although the present invention relates to the general field of liquid sample introduction to gas phase or particle detectors, most previous work in this field has focused on LC-MS.
is concentrated on. This is because this poses a significant obstacle to interface design. Therefore, this prior art interrogation focuses on LC-MS.

Complex gas phase detectors (ie, mass spectrophotometers) detect gas phase ions formed by various mechanisms. Electron impact (El) ionization and chemical ionization (cI) are the most commonly practiced methods. When using El ionization, a sample gas of 10-3 to 10-8 Torr is bombarded with electrons of sufficient energy (generally 70 eV),
The electron energy level of the sample molecule is excited above the ionization potential, removing electrons from the sample molecule and turning it into a positive ion. During the formation of sample ions in the El mode, excess energy applied to sample molecules from impinging electrons causes bond cleavage or fragmentation. The present invention provides a technique that has a wide range of applications for the analysis of samples with a characteristic and reproducible mass of El fragmentation suggesting molecular #IS structure and an unknown composition. On the other hand, the CI system is operated at a higher pressure (!1 Torr for the Q type) compared to the El system.
, thus ionization occurs due to collisions between sample molecules and reagent gas ions. Analytical applications of CI are generally found when molecular weight information is present. In the case of CI, the limited and irreproducible fragmentation of sample molecules is a major drawback. It should be emphasized that the ionization step ultimately determines the qualitative information obtained with the mass spectrophotometer. Another ionization technique is atmospheric pressure ionization (AP) at 760 Torr.
I) and field ionization at 10-4 Torr.

To obtain maximum information for a given sample, El and C
Preferably, various ionization techniques are used, including I. Additionally, LC-MS techniques that impose limitations on ionization conditions are limited only to the sample information that can be obtained for a given analysis.

The mass spectra of many compounds (compounds that are generally ionized under E1 conditions) are compiled in large computerized database archives, and these are combined into spectra (fragment ions) obtained from samples of unknown composition. and then compare.

Therefore, the use of this type of spectral archive is advantageous since computer comparisons can be made in seconds.
This is a significant advantage of MS devices. Therefore, for widespread use, it is necessary to use the EI ionization method for LC-MS instruments. Unfortunately, only a few prior art devices are reported to have the ability to generate EI spectra of thermally unstable and/or non-volatile compounds.

Effluents from either liquid chromatographs or liquid process streams must be processed by mass spectrophotometric interface techniques. As mentioned above, the pressure requirements for ionization depend on the mode of ionization and are limited by the mass flow to the ionization region of the mass spectrophotometer and the pumping power of the mass spectrophotometer. 1~2d/min
The evaporation of a flowing liquid can generate about 111 gas samples per minute under standard conditions, which corresponds to 1082 gas samples per minute at 10-5 Torr (i.e. E1 conditions), which is higher than conventional far exceeds the pumping power of mass spectrophotometers. Ionization techniques such as those produced by 1 mm tor or greater pressure saws, such as CI, require much lower pumping power, but generally pose significant ion-molecule reaction chemistry problems, which result in less structural fragmentation information. bring about.

Due to the low pressure requirements for EI ionization, direct introduction of a continuous flow of liquid from a liquid chromatograph is difficult to achieve without the use of extremely large and capable pumping systems, such as cryogenic pumping.

Evaporation or desorption steps that convert the sample to a gas can also result in thermal degradation (pyrolysis), reactions, or rearrangements of the initial sample molecules. These sample losses are greatest for thermally labile and/or non-volatile sample components that are typically separated by liquid chromatography. Mass spectrometry of these thermally sensitive and/or non-volatile molecules is generally limited by the inability to generate complete gas phase ions of these compounds. Therefore, it is important to develop an interface between LC and MS that vaporizes the sample with minimal degradation or loss of analyte.

Various methods exist for interfacing LC with MS, and this work has been extensively reviewed (see Reference 1.2 below).
．． 3.4). A common goal of all interface technologies is efficiency in the generation of gas phase sample ions.

Direct liquid introduction (DLI) is one of the simplest ways to interface LC with MS. In the case of DLI, the effluent from the liquid chromatograph flows through small circular apertures or dupes having a diameter on the order of 3 to 10 chambers. A high velocity cylindrical liquid jet is directed into this ionization chamber. There are many types of designs using this method, all of which have the same basic arrangement (discussed in references 5 and 6). The jet may pass through a heated desolvation zone to facilitate solvent evaporation before entering the ionization zone. Typically, this technique has been limited to micropore LC flow rates of less than 100 d/min. For direct introduction of liquid into the ion source, a cryo-pump is used to trap excess sample on the outside cold surface of the ion source. For normal LC flow rates, ie 1-2 m/m111, the effluent is split leaving only a portion of the sample to be sampled into the mass spectrophotometer. Another limitation of the DLI technique is that the resulting spectra provide little CI data. That is, E
In contrast to I, little or no information is obtained. In general, to keep the mass spectrometer pressure low enough,
A costly differential pump is required. Actually, DL
I have the problem that the small size orifices repeatedly become occluded, making the process cumbersome and significantly delayed. Coherence and instabilities in liquid jets of small dimensions also make DLI experimentally difficult in that the data obtained is noisy and non-reproducible. However, the advantage of this technique is that thermal decomposition does not occur when partitioning thermolabile compounds. A general discussion of this technology can be found in U.S. Pat. .

Mechanical transport (MT) is an LC where the effluent from the LC is deposited onto a moving surface such as a wire or belt.
- MS method. Heat is applied to the sample and mechanically transported through the ivy to the low pressure ion source of the 'tR quantity spectrophotometer. El and C
1 q of I amphiphilic suspended spectrophotometers have been produced using this technique. A limitation of this technique is that the sample must be evaporated or desorbed from the moving surface before ionization.

Pyrolysis may occur during the thermal evaporation process. The operation of mechanical transport equipment is often complicated by the complexity of machining and the obstruction of moving parts. The chromatographic profile of the sample can be degraded by uneven application of the sample to the moving surface. This method is described in U.S. Pat. No. 4,05, dated November 1, 1977.
It is explained in detail in Japanese Patent No. 5,987.

Thermal nebulization (TSY) is the most widely used method for LC-MS. The effluent from the LG flows through the thermal vaporizer into the heating vaporization chamber in the ion source region of the MS.

A thermal vaporizer converts the sample into an ion vapor plasma in a vaporization chamber. A small fraction of the ion vapor is sampled through a small aperture into the ion optical region of the t4 spectrophotometer. The efficiency of collecting analytes through the pores during one sampling is extremely low. Most of the ionic vapor is exhausted via the male path connected to the vaporization chamber. As with DLI, a costly differential pump between the ion optics region and the mass analyzer region is required to maintain sufficient vacuum. The vaporization process generates reagent ions in the gas phase when a buffer solution, such as aqueous ammonium acetate, is pumped through a thermal vaporizer. This ionization method, known as thermal spray ionization, yields spectra similar to CI. Under normal operating conditions, thermal decomposition was observed with the use of a thermal vaporizer. However, a large number of thermolabile compounds have been analyzed with minimal decomposition by this technique. TSY has several limitations, most notably the absence of structural information such as that available on El ionized striae. The response of various compounds is
Depends on the chemical nature of the substance being analyzed. As a result, it is often difficult to predict the response to poorly characterized samples. The thermal spray method is described in detail in Canadian Patent No. 1,162,331, dated February 14, 1984, and U.S. Patent Application No. 527.751, filed August 30, 1985, and its sequels. .

Monodisperse Aerosol Generation Interface (MAG) for Combining Liquid Chromatography and Mass Spectrophotometry
IC) is a method for LC-MS in which the effluent is pumped through a small orifice or tube to form a stable liquid jet. The liquid jet is broken into droplets of uniform size or monodisperse. These droplets are dispersed by a dispersion gas in a desolvation chamber with a pressure close to atmospheric pressure,
This dispersion gas prevents droplet agglomeration and introduces thermal energy to the droplets, resulting in rapid desolvation. This method requires a large diameter desolvation chamber at near atmospheric pressure to enable efficient desolvation. The effect of lowering the pressure in the desolvation chamber at the rate of solvent evaporation is theoretically handled by waxes and stugenes (16).

The evaporation rate of droplets decreases significantly with decreasing pressure.

In the absence of a dispersing gas, the droplets receive insufficient thermal energy to prevent their complete desolvation.

A flow rate of dispersion gas of greater than 11 per minute is used to maintain a sufficiently high pressure within the desolvation chamber. For quick desolvation, the solute particles from which the solvent has been removed are accelerated into a vacuum chamber through a nozzle to form a high-velocity aerosol beam. In contrast to the heavier solute particles, the lighter solvent vapor and dispersed gas expand outward from the axis of the aerosol beam, resulting in a calibrated particle beam free of gaseous components. The gaseous components of the aerosol beam are removed in a two-step pressure reduction step performed by directing the particle beam through two successive skimmers separating two successive low pressure vacuum chambers. The solute particle beam enters the ion source region through a skimmer;
The concentrated solute is now thermally desorbed from the surface in the ion source region and ionized by conventional CI or El ionization techniques.

The MAGIC method for LC-MS has the advantage of ionizing solutes under E1 conditions. However, the need for near-atmospheric desolvation significantly reduces solute transport efficiency for low-pressure ion sources in mass spectrophotometers. Addition of dispersion gas at high flow rates causes turbulence in the nozzle, and a significant reduction in transport efficiency is observed due to impact on the skimmer and nozzle surfaces as well as the walls of the desolvation chamber. Additionally, the need for multiple gas ports also tends to increase the solid angular expansion of the particle beam and involves the use of less efficient two-stage separation devices. Because of these conditions, the efficiency of solute transport into the ion source is typically on the order of 5%. M.A.
In the case of GIC, the composition of the mobile phase does not affect the response for various analytes, as does thermal spray techniques, which would be required if mobile phase additives were used for sensitive responses. Additionally, if El ionization is the only method used,
No differential pumps are required with this technology. Details regarding this technology are generally described in US patent application Ser.

MAGI C can be thought of as a particle beam introduction technology. To examine this, the introduction of a particle beam accelerates the aerosol through a nozzle into successive vacuum chambers and skims the aerosol particles on-axis, forming a particle beam and moving the gas component of the aerosol beam off-axis. It is thought that this is a technique for pumping and removal. The result of this method is the efficient separation of aerosol particles from gaseous substances, which are more efficiently transported into low pressure regions due to their higher moment compared to gas molecules.

The conventional particle beam introduction technique for mass spectrophotometry is 2
(1) Real-time aerosol monitoring (References 7-9); and (2) Liquid sample introduction where the aerosol generation step precedes the particle beam introduction (Reference 1).
0-14).

MAGIG technology is a brilliant example. In general, the present invention also includes a particle beam solute enrichment step when applied to sample introduction into a mass spectrophotometer.

The performance of particle beam introduction techniques depends on the nature of the aerosol. The solid angular dispersion of the particle beam depends on the solute particle size, the pressure from the aerosol source, and the nozzle geometry. Israel and Friedlander (Reference 15)
The relationship of these parameters to particle beam dispersion is experimentally demonstrated.

The results show that: (1) the angular dispersion of the particle beam increases with the aerosol source pressure; (2)
The angular dispersion of the particle beam decreases with increasing particle jJ method: (3) The expansion of the particle beam becomes more uniform as the particle size changes when using a capillary tube for the converging nozzle. Therefore, the nature of the aerosol generation process as flow rate and pressure of the scum and particle size and distribution ultimately determine the efficiency of particle beam introduction.

For particle beam methods of liquid sample introduction into mass spectrophotometers, various aerosol generators have been used. These include the monodisperse aerosol generators of Hergrundoliu (refs. 8.10-14), the monodisperse aerosol generators of Willoughby-Browner (refs. 14), and the DeVilbiss and ultrasonic nebulizers (refs. 10-13).

A major limitation with conventional particle beam beads has been the difficulty in desolventizing the aerosol droplets after aerosol generation. Prior techniques either required a desolvation chamber to remove solvent from the droplets or increased gas loads. Approximately 101 mm in diameter for conventional aerosol generation technology
J! Generation of more than n droplets tends to result in greater particle loss in the desolvation chamber and nozzle due to impact or settling processes. In the aerosol generation method of the present invention, droplets 1
It is designed to allow precise control over aerosol properties including directionality, directionality and evaporation rate.

Improved control over the aerosol generation and desolvation steps increases the efficiency of particle transport to various detectors.

The solid angular dispersion of a particle beam has been shown to increase with increasing pressure of the aerosol source (Ref. 15). Therefore, conventional particle beam technologies that require high gas loads for aerosol generation or desolvation tend to have more divergent particle beams. This requires that only a portion of the particle beam cross section be sampled via the axial skimmer. This is because the subsequent pressure in the chamber exceeds the upper limit pressure of the detector. Therefore, in theory, the entire cross section of a smaller divergent particle beam could be collected with the same skimmer diameter, and
It would be possible to maintain the same detector pressure. The result of a less divergent particle beam allows for more efficient sample transport to the detector. Consequently, the aim of the device according to the invention is to reduce the gas load from the aerosol generation process and improve sample transport efficiency.

The use of particle beam techniques for sample introduction into the 'dfJi spectrophotometer i emission has shown the ability to generate spectra under potential impact ionization conditions (References 7-14). The main purpose of the device according to the invention is to improve the ability to vaporize particles after the particle beam enters the ion source region of a mass spectrophotometer. The purpose is to form a complete gas phase molecular species derived from the particles. Conventional particle beam sample introduction devices have difficulty forming complete molecular ions due to thermal fragmentation of molecules during evaporation from heated surfaces (Reference 8). The particle vaporization process depends on the equilibrium surface vapor pressure of molecules originating from the particles, the temperature and material of the particle beam collection surface, and the presence of other components in the particle matrix. Control of these factors is essential to the performance of the device according to the invention.

Other applications of liquid sample introduction for gas phase or particle detectors are light scattering (Reference 17), flame ionization (Reference 18)
, has been reported on atomic absorption or emission spectrophotometry (Reference 19). The improved control of aerosol generation, desolvation and solute concentration by the device of the present invention can be applied to a variety of detectors.

The documents mentioned in the above prior art are as follows: 1.
P, J, Arpino, Journal Chromatography;
Volume 323, page 3 (1985).

2, D, E, Geim, Advanced Chromatography, Volume 21, Page 1 (1983) 3, C, G
, Edmond, J.A., McCloskey, V.A., ■Domond, Piomdian suspended spectrophotometry, Vol. 10, No. 23.
7 pages (1983) 4, R.C., R.R.
F. Brauner, Trace Analysis, Volume 2, No. 6
9 pages, edited by J. F. Lawrence, Academic Press (1982).

5, W. M. A. Niessen, Chroma 1-Graphia, Vol. 21, p. 5 (, 1986).

6, W.M.A., Niessen, Chromatographia;
Volume 21, page 5 (1986).

7. J. Stotzfels, "Direct Air Sampling Inlet for Surface Ionization Spectroluminescence Methods of Airborne Particles," Presented at the 24th Annual Meeting of the ASMS, San Diego, California, 1976.

8. M.P., Sinha, C., E.N.G., D.
Norris, G., and Friedlander, S. [Analysis of Aerosol Particles by Mass Spectrophotometry J, Presented at the 28th Annual Meeting of the ASMS, New York, New York, 1980.

9, J. Allen and R. Gould, review.
Science, Inmetsu Lumens 1-1 Volume 52, No. 6, June 1981.

10, F. T. Green, [Particle Impact Mass Spectrophotometry J, Presented to the 23rd Annual Meeting of the ASMS, Hyuston, Texas, 1975.

11, F.T., Gri-1 [Mass Spectrophotometry of Nonvolatile Substances and Solutions by Particle Bombardment Techniques J, 1976, 2nd ASMS, San Diego, California.
Submitted to the 4th Annual General Meeting.

12, F., T. Green, [Particle VFR1 Spectrophotoluminescence Development J. Presented to the 29th Annual Meeting of the ASMS, New York, New York, 1980.

13. F., T. Green, [Current Status of Particle Impaction Spectrophotometry J, Presented to the 29th Annual Meeting of the ASMS, Minneapolis, MN, 1981.

14. R, C, Lairouby, [Study on the aerosol generation interface between liquid chromatography and mass spectrophotometry], PhD thesis, Gyorja University of Technology, 1983°15, G, W, Israel and S,
Friedlander, Journal Colloid Interface Science, Volume 24, Page 330 (19
67) 16. N. A. Fuchs and A. G. Stugen.
"Highly Dispersible Aerosol", Arbor Science, Ann Arbor (1970).

17, J.W., Jorgenson, S.T., Smith and M. Novotny, Journal Chromatography, Vol. 142, p. 233 (1977).

18, E. Harkti and Wang, Nilakari, Acta Chemi-Riki Scandinavia, Vol. 17, p. 2565 (
1963).

19, R, F, Prowner and A, W, Pawn,
Analytical Chemistry, Volume 5677, No. 787
Page A (1984).

The disclosures of these documents are incorporated herein by reference.

SUMMARY OF THE INVENTION The present invention is a method and apparatus for introducing a process stream, liquid inlet stream, or effluent from a liquid chromatograph into an analytical instrument to a gas phase or particle detector. It can be applied to introduce liquid samples into mass spectrophotometers, flame ionization detectors, light scattering detectors and other devices suitable for determining the properties of analytes in gas phase or particulate form. Can be done.

The basic processes occurring in the device of the invention are aerosol generation and desolvation, concentration of the solute, and detection of the solute by a suitable gas phase or particle detector.

Aerosol generation according to the invention is obtained by concentric flow of a liquid stream (inner stream) and a gas stream (outer stream). The gas is heated by direct contact with a heat source, typically a heating tube that encloses the gas.

The tube is heated by controlled resistance heating of the tube or by direct contact of the tube with a cartridge heater. By accurately adjusting the flow of gas into the outer tube, the flow of liquid into the inner tube, the dimensions of both tubes, and the power to the heat source,
The properties of the aerosol are accurately determined. The heat is introduced via a gaseous medium, so the gas preferably has a high thermal conductivity, eg hydrogen, helium.

The amount of heat supplied to the liquid via the gaseous medium determines the degree of solvent desolvation or evaporation that occurs during the aerosol generation process. The gas supply serves two functions in aerosol generation. First, it provides the heat necessary for desolvation. Second, it confines or seals the aerosol particles, preventing them from widespread dispersion and providing an expansionary shock against the chamber walls. The device of the present invention does not require a desolvation chamber because the evaporation of the solvent occurs within the body and within the inner tube of the aerosol generator.

Controlled aerosol generation and desolvation by the apparatus of the present invention effectively separates the solvent from the solute since the solute generally has lower volatility than the solvent. The solvent is in the gas phase and remains in the solute mass particle state.

After phase separation, the solute is concentrated by one of two methods. The first method of solute concentration is to separate the solvent from the solute in a particle beam or moment separator, where higher moment solute particles are effectively transferred into successive low pressure regions separated by skimmer apertures. will be transported to. The apparatus of the present invention utilizes either one-step or two-step particle beam pressure reduction. The particle beam configuration in the device of the present invention transports most of the solute to the low pressure detection region while removing over 99% of the solvent. A second method of solute enrichment separates the solvent from the solute due to the mobility of the particles compared to the gas. Gaseous solvent components of the aerosol with higher mobility interact significantly with the cold surface and become trapped on the surface (ie, cryogenic traps). The solute mass in particulate form is carried in the gas stream by a less condensable carrier gas such as helium or hydrogen, leaving behind a solvent vapor.

A combination of cryogenic trapping and particle beam solute enrichment is a third alternative.

Detection of concentrated solutes by the device of the present invention can be performed by various means. One embodiment of the invention uses particle beam condensation to direct solute particles to an ionization source of a spectrophotometer. The particle beam intersects with various means of surrounding primary ion beams, laser beams, discharge plasmas, electron beams, electric or magnetic fields. Under these operating conditions, solute evaporation and ionization energy is delivered directly to the solute particles during flight. Other embodiments use target surfaces to collect solute particles. The target surface is generally composed of an inert material at a controlled temperature and serves to supply heat to the particles to obtain rapid solute vaporization v1. After the solute is vaporized, e.g. electrons! Ionization is effected by conventional gas phase methods such as ionic bombardment or chemical ionization. The target surface containing the collected particles can be bombarded with neutral ions or an electron beam to generate gas phase ions from the target surface. Alternatively, solutes are collected on a cold target surface for a period of time before heating the target to concentrate the sample and reduce the detection limit. Measurements of the power delivered to the target are also used to determine the heat of vaporization.

The use of other gas phase detectors, such as flame ionization detectors (FID), requires cryogenic pumps for solute concentration and hydrogen as the atomizing gas. This embodiment operates with an atmospheric or low pressure flame.

In general, particle beam embodiments are used in laser scattering or continuous light scattering measurements and function as universal liquid chromagraph detectors.

[Examples] Hereinafter, the present invention will be further described by way of examples with reference to the accompanying drawings.

The device of the invention comprises three parts: an aerosol generator 14, a solute concentrator, and a solute collector or detector.

The first of these components, the aerosol generator 14, will be described in detail with reference to FIGS. 1 and 2.

Liquid flows into the aerosol generator 14 from a source 30 and gas from a source 31 . Gas flows through tube 11 and liquid flows through tube 10. Important to the operation of the aerosol generator 14 is that the tube 10
and 11 to supply heat coaxially to the flowing liquid in the tube 10 via a flowing gas medium between the tubes 10 and 11. The dimensions of these tubes and the flow rates of gas, liquid and heat determine the nature of the aerosol generated.

Liquid source 30 for an aerosol generator according to the invention
is an effluent from a liquid process stream, liquid chromatograph, or liquid injection stream (i.e., an effluent containing the dissolved analyte of interest in addition to other less volatile components, either naturally occurring or intentionally added). It is. Fused silica capillary 10
acts as a nozzle to confine the flow of effluent. The tube 10 limits the liquid flow to increase the linear velocity of the liquid flow and the surface contact between the liquid and the heated wall of the fused silica capillary per unit volume. The inner diameter of fused silica capillary 10 has a dimension determined by the liquid flow rate requirements for a given application. tube 10
The minimum inner diameter of is determined by the upper pump pressure of the liquid source 30. The liquid flow rate, length and inner diameter of the tube 10 have no effect on the liquid supply pressure. The mulberry dimensions of the fused silica capillary for liquid flows in the range of 0.1 to 2.0 d/min are 501 JIII inner diameter and 250 III outer diameter. The inner diameter of the tube 10 is 10
M1, 25jIllI, 50m 175mm and 100 legs have been successfully tested. The length of the fused silica capillary is long enough to allow heat transfer to the liquid stream; the capillary length is 20 CI11.

The maximum length of the fused silica capillary 10 is determined by the pressure limits of the liquid pump system.

The gas supply 31 to the aerosol generator 14 consists of a compressed or spontaneous controlled gas source of a conductive gas or gas mixture. A coaxial metal capillary tube 11 seals the fused silica tube 10 and restricts the flow of atomizing gas supplied from a controlled gas source 31 and controlled by a precision valve 35 (see FIG. 3). The inner diameter of the metal capillary tube 11 and the gas flow rate from the supply source 31 determine the linear velocity of the gas flowing through the metal capillary tube 31, and thus also the linear velocity of the concentric sealing gas 33 in the aerosol generation process. Concentric gas flows serve two functions in the device of the invention. First, the aerosol exiting the fused silica capillary 10 is sealed off. Second, it acts as a conductive medium for heat transfer from the heated outer metal capillary 11 to the inner fused silica capillary 10.

The heat supply of the aerosol generator according to the invention is provided by a metal capillary tube 1.
1 of electrical resistance, which heats the tube. FIG. 1 shows a means for increasing the temperature of the capillary tube 11 by supplying heat by passing an electric current. The tube is the resistive heating part of the heating circuit. The length, composition and wall thickness of outer tube 11 determines the power requirements of heating power supply 20, which is controlled by heater controller 23. The heating circuit is controlled by maintaining a constant resistance in the circuit or by thermocouple feedback 24 to maintain a constant temperature. The heated outer tube 11 is preferably constructed of pure metal, such as nickel or platinum. This is because temperature is proportional to the resistance of this kind of pure metal, or many pure metals. This relationship allows control of heat supply or temperature by direct resistance feedback measurements without the need for thermocouple feedback control. Furthermore, the device according to the invention can also use thermocouple feedback for heat supply control and resistively heated alloys other than pure metals. The resistive heating circuit is electrically isolated from ground by suitable means, such as, for example, insulators designated by reference numerals 12 and 13. The inner diameter of the heated metal capillary 11 is slightly larger than the outer diameter of the inner fused silica capillary 10. The curved range for the inner diameter of the tube 11 is 300 to 400 marks. In this range, the gas velocity is high enough to entrain the liquid jet or aerosol generated from the fused silica capillary 10 at location 32.

In general, the gap spacing is sufficiently small to allow efficient heat transfer through the gas to the fused silica capillary tube 10. There is a section of the capillary tube 11 which is not part of the resistively heated circuit and which is connected to the heated section of the tube 11 by an electrically insulating union 12. The region surrounding the outer metal capillary 11 conducts heat to the inner fused silica tube 10 at a rate slower than the rate of heat transfer. As a result, the outer tube is insulated by air spaces, insulating materials or vacuum to ensure heat transfer to the flowing liquid stream.

FIG. 2 shows an alternative means of supplying heat to the metal capillary tube 11 by cartridge heating. Cartridge heater 26 is inserted into a metal block that is in thermal contact with metal capillary tube 11 . When using car 1 ~ Ritsuji heater,
The control means for heater power supply 20 is thermocouple feedback 24 to controller 23 .

The heated portion of the aerosol generator is contained within a protective housing 28, which serves to support the aerosol generator and protect the operator from voltage burns or electrical shock. The aerosol generator has a connection 29 which may be a gasket or an O-ring seal or both.
attached to the aerosol expansion chamber via.

Aerosol generation by the device of the invention is achieved by combining coaxial flows of liquid, gas, and heat in a precisely controlled manner. The aerosol is generated at location 32 and is trapped by sealing gas 33 along the axis in the direction of flow. Coaxial heat transfer to the flowing liquid is controlled by an electrical feedback circuit and the flow of gas between the outer heated metal tube 11 and the inner fused silica capillary 10, which gas is a conductive medium passing through the interstitial space. The thermal conductivity of the gas is a critical parameter in the transfer of heat to the inner fused silica tube 10. It is preferred that the gas source constitutes a highly conductive gas, such as hydrogen or helium, but this does not exclude other gases or gas mixtures that are less conductive.

Suitable operating conditions for an aerosol generator according to the invention depend on the required aerosol characteristics for a given application. The range of aerosol properties varies from pneumatically atomized solvent-rich aerosols with relatively large diameter droplets to thermally atomized solvent-stripped aerosols with relatively small diameter droplets. The combination of pneumatic method and thermal spray method is
Variations in the droplet 1 method, the degree of desolvation of the droplets and the direction of flow of the generated aerosol result in a controlled aerosol, which functions to produce desolventized solute particles as described above.

Aerosols generated by the apparatus of the present invention require a solute concentration step in embodiments where solute detection is impaired by the presence of relatively large amounts of solvent. The device according to the invention is particularly applicable to effluents in which the solute is generally less volatile than the associated solvent or solution. Differences in volatility between solvent and solute result in the solute being primarily present in the particle portion of the aerosol and the solvent being primarily present in the vapor portion of the aerosol. Figures 3-5 illustrate embodiments of the invention with aerosol generation, particle beam solute enrichment, and mass spectrophotometric detection.

FIG. 6 illustrates an embodiment of the present invention for aerosol generation, solvent cryogenic trapping for solute concentration, and flame ionization detection. Although the use of the device according to the invention for detection by aerosol generation, solute enrichment and other detection methods is not illustrated, the modifications necessary to do this are in the gas phase or in the technique of liquid sample introduction into the particle detector. It will be apparent to those skilled in the art from the embodiments disclosed herein.

FIG. 3 shows an embodiment of the invention for a single stage particle beam solute enrichment. This device has a seven-lung vacuum joint 6 for an ion source chamber 60 with mass spectrophotometry h1.
Attached via 2. The above aerosol generator is
8 are attached to the aerosol expansion chamber 40 by the sealing joint 29. Expansion chamber 40 provides sufficient space for the high velocity aerosol generated at location 32 to slow down to the viscous flow range and travel in the direction indicated by the dashed lines and arrows. The pressure in the expansion chamber can vary from near atmospheric to 1 Torr, depending on the material flow rate from the aerosol generator. The solute particles and solvent vapor are transferred to the nozzle 42.
is accelerated therein to form a high velocity aerosol beam along the longitudinal axis between the nozzle 42 and the skimmer 43. The pressure drop between the expansion chamber 40 and the vacuum chamber 41 forms a beam. The decompression chamber 41 is depressurized by the pump 44,
Generally, it is a mechanical pump having a large pumping capacity, such as a rotary pump of 40 ON/min.

In the region between the axially aligned nozzle 42 and skimmer 43, the solvent vapor from the aerosol and the conductive gas expand much more rapidly than the solute particles.

As a result of the differential expansion of the gas and particles, the particles become highly concentrated along the axis of the expanded aerosol beam. The concentrated solute particles are sampled via skimmer 43 into the ion source chamber of the mass spectrophotometer. A concentrated solute particle beam is formed from the skimmer to the ionization region 61 of the mass spectrophotometer. The distance between the point where the aerosol beam is formed at nozzle 42 and the ionization region should be kept to a minimum, typically between 5 and 1Q cm.

FIG. 4 shows an embodiment of the invention for two-stage solute beam concentration. As described with respect to FIG. 3, this device is attached to the ion source chamber 60 of a commercial spectrophotometer via a flange joint 62. The aerosol generator has an aerosol expansion chamber 4 via a sealing joint 29.
0. The aerosol expands axially from the aerosol generator at location 32 and travels downstream along the axis of the expansion chamber in the direction indicated by the dashed lines and arrows.

The aerosol is accelerated in the nozzle 42 and
and the skimmer 43 to form a high-speed aerosol beam. This aerosol beam is formed by the pressure drop between the expansion chamber 40 and the first vacuum chamber 41 . The second vacuum chamber 46 provides a higher degree of solute concentration by roughly pumping away solvent vapor in the region between skimmer 43 and skimmer 49. The first decompression chamber 41 is depressurized by the pump 44, and the second decompression chamber is depressurized by the pump 45. Pumps 44 and 45 have sufficient pumping capacity to remove most of the solvent vapor introduced by the aerosol generator. Nozzle 42 and skimmers 43 and 4 are axially aligned as before to permit sampling of concentrated solute particles into a region of progressively decreasing pressure. The distance between the nozzle 42 where the aerosol beam is formed and the ionization region 61 is minimized to ensure the efficiency of solute particle movement. This distance is typically between 1 and 1Q cm.

FIG. 5 shows an embodiment of the invention for two-stage solute particle beam concentration, which is an alternative to the embodiment shown in FIG. This device is removable from the ion source chamber 60 of the mass spectrophotometer through a standard gate valve 64. The insertion probe portion 65 of the device is inserted into a gate I valve 64 (which opens and closes automatically) and is axially aligned with the ionization region 61 of the Q spectrophotometer. The aerosol generator opens the aerosol expansion chamber 4 at the sealing joint 29.
0. The aerosol expands axially from the aerosol generator at location 32 and travels downstream along the axis of expansion chamber 40 in the direction indicated by the dashed lines and arrows. The aerosol is accelerated in the nozzle 42 to form a high velocity aerosol beam between the nozzle 42 and the skimmer 43. This aerosol beam is formed by the pressure drop between the expansion chamber 40 and the first vacuum chamber 41 . A second vacuum chamber 46 provides a higher degree of solute concentration by pumping away more solvent vapor in the region between skimmer 43 and skimmer 49. The first decompression chamber 41 is depressurized by a pump 44, and the second decompression chamber is depressurized by a pump 45. Pumps 44 and 45 have sufficient pumping capacity to remove most of the solvent vapor and conductive gas introduced by the aerosol generator. Nozzle 42 and skimmers 435 and 49 are axially aligned as above to allow sampling of concentrated solute particles into a region of progressively decreasing pressure. The distance between the nozzle 42 where the aerosol beam is formed and the ionization region 61 is minimized to ensure solute particle transport efficiency. However, with this embodiment, additional length for the intervening probe 65 is required. This distance generally ranges from 20 to 4 Qcm.

Additionally, FIG. 5 shows an optional attachment 67 that may be introduced into the ion chamber 60 adjacent to and surrounding the special purpose ionization region 61. For example, the installation is done in part 67.
can be a radar, which allows the laser beam to be focused on the surface of target 61 and subject the beam to photoionization and laser desorption analysis. Roughly,
The attachment portion 67 can also constitute an electron source for chemical ionization or a high voltage source to ionize particles and molecules by discharge or electric field ionization.

Still further, the mounting 67 may be configured with a cryogenic trap for collecting the solvent vapor onto a cold surface and passing the solute particles to a cold trap for subsequent detection. Another form of mounting 67 is a device for providing an optical region transverse to the axis of the particle beam to perform light scattering measurements on the beam.

The mounting 67 can also consist of a support for a roughly moving target (i.e. a belt 68 shown in dashed lines), which collects solute particles as a function of time and also supports a device incorporated into the mounting 67. (i.e. a separate device) locates and analyzes the received chromatographic profile by surface measurements, such as SIMS, infrared, X-ray, ultraviolet or visible spectrophotometric scanning, or by, for example, reflection or transmission measurement techniques. In addition, belt 68 can also collect highly purified solute crystals for subsequent structural analysis. The belt 68 or its equivalent (eg, disk or moving band) can also be heated to perform on-line continuous thermal analysis.

In this case, the attachment 67 may also include means for coarsely heating the target, controlling this heat, and accurately measuring the thermal energy consumed by evaporation or desorption of solutes from the target.

The attachment 67 may constitute a device for generating a high-energy discharge having sufficient energy to charge the surfaces of particles in the beam and thereby increase ion desorption or particle fragmentation with Coulombic forces. .

Attachments 67 can be built-in, or preferably easily removable, and a plurality of attachments 67 can be placed within chamber 60 in operational proximity to target and region 61, such that they are They can be used alone or in combination as desired.

The concentrated particle beam generated by the embodiment shown in FIGS. 3-5 similarly converts solute particles into gas phase ions. In each of these devices, solute particles are collected onto a target surface 50. Target surface 50 is a resistively heated surface that vaporizes solute molecules by delivering thermal energy to tiny solute particles. The target is inserted into the gate valve 63 to cause vaporization of the solute to occur in the ionization region 61 of the mass spectrophotometer. The temperature of the target surface 50 is controlled by a controller 52 with thermocouple feedback 53 and a power supply 51 . The recovered solute particles are heated at low temperatures for heat-sensitive compounds and at high temperatures for non-volatile substances and sprays.

The operating temperature range of target surface 50 is typically 100°C to 300°C.
℃ range. Ionization of gas phase solute molecules is effected by conventional ionization methods, such as electron bombardment or chemical ionization.

The ionization process that occurs in the apparatus described with reference to FIGS. 3-5 is not limited to gas phase ionization only. The solute particle beam is further collected onto a target surface 50, such as by rapid atom bombardment, secondary ion mass spectrometry, field desorption,
Ionization is accomplished by conventional surface ionization techniques such as thermal ionization, plasma IB2 deposition, and laser desorption as described with reference to FIG. These techniques require the introduction of alternative energy sources to the target surface. In addition to surface ionization methods, the device according to the invention allows for the introduction of energy directly into the solute particle beam without the need to retrieve the particles from the surface prior to ionization. According to this embodiment, target surface 50 need not be present. During flight, the solute particle beam intersects with a primary ion beam, primary atomic beam, laser beam or high electric field region.

FIG. 6 illustrates an embodiment of the invention with solvent cryogenic trapping providing solute particle concentration. The aerosol generator is attached to the aerosol expansion chamber 40 at a sealing joint 29. The conductive gas used for aerosol generation according to this example is hydrogen gas. The aerosol expands axially from the aerosol generator at location 32;
and proceed downstream along the axis of the expansion chamber in the direction indicated by the dashed line and arrow. The walls of the expansion chamber 40 are cryogenically cooled to trap solvent vapors. Solute particles and hydrogen gas pass through the expansion chamber more efficiently than solvent vapor. The concentrated solute particles and hydrogen gas enter the burner chamber 7 through the inlet lower 0.
It will be introduced into 1. Here, the particles are burned in a hydrogen flame and the generated ions in the flame are collected on the electrode grid 73.

Air or oxygen is introduced into the burner chamber 71 via the entry lower 2 .

Although the present invention has been described in terms of specific embodiments that will be readily understood by those skilled in the art, this should not be construed as an unnecessary limitation. The cited prior art patents, documents, and patent applications are provided to assist those skilled in the art in understanding the invention and are not intended to limit the invention in any way.

[Brief explanation of drawings]

Figure 1 is a schematic cross-sectional view of a thermal concentric aerosol generator using resistance heating of conductive aerosol generating gas, and Figure 2 is a schematic cross-sectional view of a thermal concentric aerosol generator using cartridge heating of conductive aerosol generating gas. Figure 3 is a schematic cross-sectional view of a thermal concentric aerosol generator and one-stage particle beam solute concentration interfaced to the source chamber flange of a conventional quality omega spectrophotometer; 5 is a schematic cross-sectional view of a thermal concentric aerosol generator and two-stage particle beam solute concentrator interfaced to the ion source chamber flange of a spectrophotometer; FIG. FIG. 6 is a schematic cross-sectional view of a thermal concentric aerosol generator and an alternative two-stage particle beam solute concentration; FIG. It is. 10... Inner fused silica capillary 11... Outer metal capillary 14... Aerosol generator 40... Expansion chamber 41.
...First decompression chamber 46...Second decompression chamber 52...
・Control room

Claims (57)

[Claims] (1) In a thermal concentric aerosol generator for obtaining solvent-free solute particles with micron and submicron dimensions in a well-defined direction from a liquid sample containing a volatile solvent and a less volatile solute: (a) an inner fused silica capillary for transporting liquid into a high velocity liquid jet; (b) an outer metal capillary coaxial to the fused silica capillary for transporting a thermally conductive gas; c) means for heating said outer metal capillary tube; (d) a tee union for connecting a source of liquid and gas to a coaxial atomizer arrangement; and (e) at a sufficient flow rate and pressure in said inner capillary tube. (f) a means for supplying a liquid; (f) a thermally conductive gas, including but not limited to helium or hydrogen, for enhancing thermal energy transport and liquid flow from the outer metal capillary to the inner fused silica capillary; (g) means for supplying said gas at a sufficient flow rate and pressure to said outer metal capillary; (h) means for supplying energy to heat said outer metal capillary; (i) means for controlling the supply of heat to the outer metal capillary, characterized in that during the aerosol generation step the solvent is evaporated and highly concentrated solute particles are entrained in the high velocity flow of the thermally conductive gas. Thermal concentric aerosol generator. (2) said means for supplying heat to said outer metal capillary comprises an electrical circuit, said outer metal capillary being a heating member of said circuit, and said outer metal capillary being connected to a relatively high straight line between temperature and resistance; 2. The thermal concentric aerosol generator according to claim 1, wherein the thermal concentric aerosol generator is made of a high-purity metal having the following properties. 3. The thermal concentric aerosol generator of claim 1, wherein said means for supplying heat to said outer metal capillary tube comprises an electrical circuit having as a heating member a standard cartridge heater in substantial thermal contact with said outer metal capillary tube. (4) an expansion chamber that is coaxial with the flow from the fused silica capillary to provide sufficient space for high velocity gas and particles to allow internal flow without significant sample loss due to particle bombardment or sedimentation; 2. The thermal concentric aerosol generator of claim 1, wherein the thermal concentric aerosol generator reduces velocity. (5) The thermal concentric aerosol according to claim 4, further comprising a supply means for heating the expansion chamber, a control means for controlling the supply means, and a detection means for monitoring the temperature of the expansion chamber. Generator. (6) further comprising a nozzle restriction coaxial with the flow of the aerosol generator downstream of the expansion chamber, the aerosol flow therefrom being accelerated in the nozzle to form a high-velocity particle beam; The thermal concentric aerosol generator according to claim 5. (7) further comprising a low pressure chamber downstream from the nozzle, the flow of aerosol discharged from the nozzle expanding outward from the axis of the nozzle, and the low pressure chamber being pumped by a high speed rotating mechanical pump or other pumping means; 7. The thermal concentric aerosol generator according to claim 6, wherein a sufficiently low pressure is maintained within the low pressure chamber. 8. The thermal concentric of claim 7, further comprising a skimmer located in the chamber axially aligned with the nozzle, the skimmer preferentially sampling solute particles compared to solvent and conductive gas vapor. Aerosol generator. 9. The thermal concentric aerosol generation device of claim 8, further comprising a mass spectrophotometer ion source region axially aligned with the solute particle beam emitted from the skimmer. (10) further comprising a second low pressure chamber downstream from the skimmer, the second low pressure chamber being pumped by a high speed rotary mechanical pump or other pumping means to maintain a sufficiently low pressure within the low pressure chamber. The thermal concentric aerosol generator described. (11) further comprising a second skimmer located in the second low pressure chamber aligned in the axial direction with respect to the first skimmer;
11. The thermal concentric aerosol generation device of claim 10, wherein solute particles are preferentially sampled by the skimmer versus solvent and conductive gas vapor. 12. The thermal concentric aerosol generation device of claim 11, further comprising a mass spectrophotometer ion source region axially aligned with respect to the solute particle beam emitted from the skimmer. (13) The thermal concentric aerosol generator according to claim 9 or 12, comprising means for directly fixing to the housing of the mass spectrophotometer. (14) In combination with a mass spectrophotometer interface,
13. The thermal concentric aerosol generation device according to claim 9 or 12, comprising an insertion probe that can be easily attached and detached from the ion source region of the mass spectrophotometer via a vacuum interlock. (15) further comprising a heated target axially aligned with the solute particle beam, the target rapidly vaporizing or flash desorbing the recovered solute particles;
15. The thermal concentric aerosol generator according to 2, 13 or 14. (16) further comprising control means for controlling the desorption and/or evaporation of solutes from the heated target: (a) converting the recovered solute particles into complete molecular forms before ionization by an electron bombardment or chemical ionization step; (b) the recovered solute particles are thermally ionized from the surface as intact molecular ions, or (c) the recovered solute particles are pyrolyzed on the target surface to form thermal fragments in the gas phase. 16. The thermal concentric aerosol generator according to claim 15, wherein the solute is formed and then ionized by conventional methods such as electron bombardment or chemical ionization, and the target temperature is adjustable to control the controlled removal of solute from the target. (17) The heat according to claim 13 or 14, further comprising means for directing a primary ion beam onto the surface of the target, and forming gas phase solute ions by sputtering recovered solute molecules from the surface of the target. Concentric aerosol generator. 18. The thermal concentric aerosol generation device of claim 15, further comprising means for focusing a laser onto the surface of the target to effect a laser desorption or photoionization process. (19) Claim 9, 12, 13, 14 or 14 further comprising a high negative voltage discharge as an electron source for the chemical ionization process and a high positive voltage discharge as a means for ionizing particles and molecules by field ionization. 16. The thermal concentric aerosol generator according to 15. 20. The thermal concentric aerosol generator of claim 1, further comprising means for collecting solvent vapor on a cold surface and passing solute particles to a cold trap for subsequent detection. (21) The thermal concentric aerosol generation device according to any one of claims 1 to 7, further comprising an optical region that crosses the axis of the particle beam, and performs light scattering measurement on the particle beam. (22) The thermal concentric aerosol generator according to any one of claims 1 to 7, further comprising a flat target aligned in the axial direction with respect to the particle beam, so that the particles collide with the surface in a narrow range. (23) further comprising a moving target for rastering across the axis of the particle beam and collecting solute particles as a function of time, for subsequent processing of the target with a chromatographic profile and for SIMS, scanning infrared, ultraviolet or visible spectroscopy; 23. The thermal concentric aerosol generator of claim 22, which can be analyzed by surface measurement techniques such as photometry. (24) The thermal concentric aerosol generator according to claim 23, further comprising a target for collecting highly purified solute crystals for later crystal structure analysis. (25) further comprising a heated target for collecting a sample for online thermal analysis, (a) means for supplying heat to the target; (b) means for controlling supply of heat to the target; (c) 24. The thermal concentric aerosol generation device according to claim 23, further comprising means for measuring heat supply to the target, to accurately measure thermal energy consumed by evaporation or desorption of solute from the target. (26) In a method for generating and transporting a highly dispersed aerosol from a solution containing a low volatility solute to introduce a sample into a detection device to concentrate the solute or purify the solute: (a) Liquid (b) directing heat into the inner liquid stream through a highly conductive gaseous medium sealing the liquid stream; (c) (i) accelerating the liquid stream in a narrow tube to increase the linear velocity and kinetic energy of the stream; (ii) introducing thermal energy into the liquid stream via a conductive gas medium; and ( iii) atomizing the liquid stream by introducing mechanical energy from the conductive gas stream into the liquid stream to change the properties of the generated aerosol by controlling the amount of each energy source added to the liquid stream; (d) (i) controlling the supply of heat to the conductive gas medium; (ii) controlling the flow of conductive gas to the outer flow region; and (iii) controlling the flow rate of the liquid to the nozzle of the aerosol generator; A method for generating and transporting a highly dispersed aerosol, which comprises controlling the supply of energy directed to an aerosol generation process by controlling. 27. The method of claim 26, further comprising a separation step of removing solvent vapor from the aerosol by cryogenic trapping of the vapor and transporting dry solute particles for subsequent detection. (28) removing solvent vapor from the aerosol by accelerating the aerosol in a nozzle to form a high velocity solute particle beam aligned axially with respect to the nozzle and pumping the solvent vapor non-axially; 27. The method for generating highly dispersed aerosol according to claim 26, further comprising a separation step. 29. The method of claim 28, further comprising the step of: directing the axial particle beam into at least two skimmers separating the plurality of differential pump chambers. (30) further comprising collecting the solvent-stripped solute particles onto a target surface for subsequent analysis, the analysis comprising: (a) evaporation and ionization for mass spectrophotometric analysis; (b) (c) an optical analysis such as infrared reflection or transmission or other optical technique using any suitable wavelength, filter or monochromator; 29. The method of generating a highly dispersed aerosol according to claim 28, comprising one or more steps. (31) The method for generating a highly dispersed aerosol according to claim 27, further comprising flame ionization detection of the particle stream, and wherein the conductive aerosol generating gas is hydrogen required for flame ionization detection. (32) Vaporization of concentrated solute particles by directing the particle beam of claim 29 into a high-energy discharge having sufficient energy to charge the surface of the particles and increase ion desorption or particle fragmentation by Coulombic precipitation. Method. (33) directing the particle beam of claim 29 to a heated surface having a surface area sufficient to collect the beam and a supply of thermal energy sufficient to vaporize the solute; Vaporization method. (34) directing the particle beam of claim 29 onto a heated surface having a surface area sufficient to collect the beam and another energy source to cause vaporization; (b) a laser that desorbs solute molecules from the collector surface using a process known as laser desorption; or (b) an ion beam that desorbs solute molecules from the collector surface using a process known as ion sputtering; or (c) ) A method of vaporizing concentrated solute particles comprising selected one or more of high voltage electric fields that desorb solute molecules from a collector surface. (35) In a thermal aerosol generation device for obtaining solvent-free solute particles having micron or submicron dimensions and well-defined orientation from a liquid sample containing a volatile solvent and a less volatile solute. (a) a capillary tube for transporting liquid into a high-velocity liquid jet; (b) means for supplying liquid to said capillary tube at a sufficient flow rate and pressure; (c) means for supplying heat to said capillary tube; d) means for controlling the supply of heat to said capillary; (e) an expansion chamber for storing high velocity particles; (f) a nozzle restriction to a vacuum chamber for forming a high velocity aerosol beam; and (g) a solvent vapor. (h) at least one skimmer separating the plurality of pumping stages for axially sampling the concentrated solute particles; A thermal aerosol generator characterized by collecting or detecting. (36) the means for supplying heat to the capillary tube comprises an electric circuit;
36. The thermal aerosol generation device of claim 35, wherein an outer capillary tube is provided as a heating element of the circuit, and wherein the outer capillary tube is constructed of a high purity metal having a relatively high linear relationship between temperature and resistance. 37. The heat of claim 35, wherein the means for supplying heat to the outer metal capillary comprises an electrical circuit, and the heating member is a standard cartridge heater in sufficient thermal contact with the outer metal capillary to uniformly heat the capillary. Aerosol generator. (38) The thermal aerosol generation device according to claim 35, further comprising a supply means for heating the expansion chamber, a control means for controlling the supply means, and a detection means for monitoring the temperature of the expansion chamber. (39) In combination with a mass spectrophotometer interface,
36. The thermal aerosol generation device of claim 35, wherein the thermal aerosol generation device is affixed directly to the housing of a mass spectrophotometer to increase transport efficiency of the solute particle beam by reducing particle beam length. (40) in combination with a mass spectrophotometer interface;
36. The thermal aerosol generation device according to claim 35, further comprising an insertion probe that can be easily attached to and detached from the ion source region of the mass spectrophotometer via a vacuum interlock. (41) The thermal aerosol generation device of claim 39 or 40, further comprising a heating target aligned axially with respect to the solute particle beam, the target causing rapid evaporation or flash desorption of the collected solute particles. (42) further comprising a control means for controlling the desorption and/or evaporation of the solute from the heated target, wherein: (a) the recovered solute particles are desorbed as intact molecular material prior to ionization by an electron bombardment or chemical ionization step; or (b) thermally ionizing the recovered solute particles from the surface as complete molecular ions when the recovered solute particles are thermally decomposed on the surface of the target to form gas phase thermal fragments prior to ionization. 42. The thermal aerosol generation device of claim 41, wherein the target temperature is adjustable for controlled removal of solutes from the target. (43) The thermal aerosol generation according to claim 41 or 42, further comprising means for directing the primary ion beam onto the surface of the target, and forming gas phase solute ions by sputtering recovered solute molecules from the surface of the target. Device. 44. The thermal aerosol generation device of claim 41 or 42, further comprising means for focusing a high power laser into the surface of the target to produce the laser desorption or photoionization process. (45) The thermal aerosol generation device according to any one of claims 35 to 40, further comprising a high voltage discharge as an ionization source. (46) In a thermal aerosol generation device for obtaining solvent-free solute particles with micron or submicron dimensions and well-defined orientation from a liquid sample containing a volatile solvent and a less volatile solute, (a) a capillary for transporting liquid into a high velocity liquid jet; (b) means for supplying liquid to said capillary at a sufficient flow rate and pressure; (c) means for supplying heat to said capillary; ) means for controlling the supply of heat to said capillary; (e) an expansion chamber for generating high velocity particles; (f) for collecting solvent vapor onto a cold surface and passing solute particles through a cold trap; or more ionization detectors, namely flame absorption, emission or fluorescence spectrophotometers, and means for selective detection by means of plasma atomic emission spectrophotometers. (47) The thermal aerosol generation device according to any one of claims 35 to 40, further comprising an optical region for cutting the axis of the particle beam, and capable of performing light scattering measurement on the particle beam. (48) The thermal aerosol generation device according to any one of claims 35 to 40, further comprising a flat target aligned in the axial direction with respect to the particle beam, so that the particle beam impinges on a surface in a narrow range. (49) further comprising a moving target that raster across the axis of the particle beam and collect solute particles as a function of time, with the target having a chromatographic contour followed by S
41. The thermal aerosol generating device of claim 40, which can be processed and analyzed by surface measurement techniques such as IMS, scanning infrared, ultraviolet or visible spectrophotometry. (50) further comprising a heated target for collecting a sample for on-line thermal analysis, the target comprising: (a) means for supplying heat to the target; (b) means for controlling supply of heat to the target; c) means for measuring the supply of heat to the target to accurately measure and relate to concentration the thermal energy expended by evaporation or desorption of the solute from the target. Device. (51) A method for heat generation of highly dispersed aerosols comprising a separation step in which solvent vapor is removed from the aerosol by cryogenic trapping of the solvent vapor and transporting dry solute particles for subsequent detection. (52) Solvent vapors are removed from the aerosol by accelerating the aerosol in a nozzle to form a high-velocity solute particle beam that is axially aligned with the nozzle and non-axially pumped to remove the solvent vapor. A method for generating heat from highly dispersed aerosols, including a separation step. 53. The method of claim 52, further comprising a depressurizing step of directing the axial particle beam into at least two skimmers separating a plurality of differential pump chambers. (54) further comprising collecting solvent-removed solute particles from the aerosol onto a target surface for subsequent analysis;
The analysis may optionally include (a) vaporization and ionization for mass spectrophotometric analysis;
or (b) X-ray diffraction analysis or other crystal or solid particle examination techniques; or (c) optical analysis such as infrared reflection or transmission or other optical techniques using appropriate wavelengths, filters or monochromators. 53. The method of generating heat from a highly dispersed aerosol according to claim 52. (55) Claim 51 further comprising ionization detection of the particle flow.
A method for generating heat from a highly dispersed aerosol as described. (56) Vaporization of concentrated solute particles by directing the particle beam of claim 53 onto a heated surface having a surface area sufficient to collect the beam and a source of thermal energy sufficient to vaporize the solute. Method. (57) directing the particle beam of claim 53 to a heated surface having a surface area sufficient to collect the beam and a separate energy source to cause vaporization, the separate energy source being selected; (a) a laser that desorbs solute molecules from the collector surface using a process known as laser desorption; or (b) a beam that desorbs solute molecules from the collector surface using a process known as ion sputtering. or (c) a method of vaporizing concentrated solute particles consisting of a high voltage electric field that desorbs solute molecules from the collector surface.