Method and device for ionizing particles of a sample gas flow

Abstract

A device for ionizing sample particles of a sample gas flow comprises a first flow tube for providing the sample gas flow, and an introducing means for providing H.sub.2SO.sub.4 molecules to an interaction region. In addition the device comprises a generator for producing reagent primary ions from particles of candidate reagent gas flow essentially in a primary ion production region. The device is configured to introduce said reagent primary ions with H.sub.2SO.sub.4 molecules in said interaction region in order to arrange interaction between the reagent primary ions and the H.sub.2SO.sub.4 molecules, thereby producing HSO.sub.4.sup. ions and again to produce HSO4.sup. ion clusters comprising HSO.sub.4.sup. ions and at least two H.sub.2SO.sub.4 molecules via interactions of HSO.sub.4.sup. with other H.sub.2SO.sub.4 molecules in said interaction region. Furthermore the device is configured to introduce said HSO.sub.4.sup. ion clusters with the sample particles of the sample gas flow in order to provide reactions between said HSO.sub.4.sup. ion clusters and the sample particles, and thereby provide a sample cluster comprising the HSO.sub.4.sup. ion clusters and said base sample to be determined.

Claims

1. A method for ionizing sample particles of a sample gas flow by an ionizer, wherein the particles comprise base molecules or clusters, wherein the method comprises following steps: a) providing H.sub.2SO.sub.4 molecules to an interaction region, b) producing reagent primary ions from particles of candidate reagent gas flow in a primary ion production region, c) introducing said reagent primary ions with H.sub.2SO.sub.4 molecules in said interaction region in order to arrange interaction between the reagent primary ions and the H.sub.2SO.sub.4 molecules, thereby producing HSO.sub.4.sup. ions and again to produce HSO4.sup. ion clusters comprising HSO.sub.4.sup. ions and least two H.sub.2SO.sub.4 molecules via interactions of HSO.sub.4.sup. with other H.sub.2SO.sub.4 molecules in said interaction region, and d) introducing said HSO.sub.4.sup. ion clusters with the sample particles of the sample gas flow in order to provide reactions between said HSO.sub.4.sup. ion clusters and the sample particles, and thereby provide a sample cluster comprising the HSO.sub.4.sup. ion clusters and said base sample to be determined.

2. The method according to claim 1, wherein said H.sub.2SO.sub.4 molecules are introduced to the sample gas flow before introduction to the interaction region in order to provide a mixed sample gas flow to be introduced to said interaction region.

3. The method according to claim 2, wherein said H.sub.2SO.sub.4 molecules are introduced from a saturator comprising H.sub.2SO.sub.4 vapour by using carrier medium, said carrier medium comprising N.sub.2 flow carrying said H.sub.2SO.sub.4 molecules to said interaction region.

4. The method according to claim 1, wherein said reagent primary ions are produced by ionising said particles of the candidate reagent gas flow using soft X-ray radiation or ionising radiation by an -source or a corona discharge source.

5. The method according to claim 1, wherein said candidate reagent gas flow comprises HNO.sub.3, CH.sub.3COOH (acetic acid), CH.sub.3I (methyliodide), H.sub.2SO.sub.4, or O.sub.2, and said reagent primary ions are NO.sub.3.sup. ions, I.sup. (iodide), CH.sub.3COOH.sup. (acetate), O.sub.2.sup., or HSO.sub.4.sup., and wherein said sample bases are bases selected from the group consisting of ammonia, amines, pyridine, quinoline, aniline, and highly oxidized organic molecules.

6. The method according to claim 4, wherein the energy of the used soft X-ray photons is in a range of 1-10 keV.

7. The method according to claim 1, wherein a sheath flow is arranged to flow at least through a primary ion production region or said interaction region between the sample gas flow and structure of said ionizer, and wherein said sheath flow comprises clean air or nitrogen, with small amounts of reagent gas molecules selected from the group consisting of nitric acid, sulphuric acid, acetic acid, methyl iodide, oxygen, ammonia, amines, alcohols, and acetone.

8. The method according to claim 1, wherein the sample gas flow and candidate reagent gas flow is configured to flow essentially concentrically at the primary ion production regions, or wherein the trajectory of the produced reagent primary ions is configured to bend inward and towards the sample gas flow at the interaction region.

9. The method of claim 8, wherein the trajectory of the produced reagent ions are achieved by using an electric field or by using flow current guiding means, said flow current guiding means comprising a deflector, wing or throttle.

10. The method according to claim 1, wherein the ionizing process is implemented essentially at atmospheric pressure.

11. A device for ionizing sample particles of a sample gas flow, wherein the particles comprise base molecules or clusters, and wherein the device comprises: a first flow tube for providing the sample gas flow; an introducing member for providing H.sub.2SO.sub.4 molecules to an interaction region, said introducing member being a saturator or a device with a space for SO.sub.2+H.sub.2O solution with a radiation source to produce H2SO.sub.4 vapour; a generator for producing reagent primary ions from particles of candidate reagent gas flow essentially in a primary ion production region; wherein said device for ionizing sample particle of a sample gas flow is configured to: introduce said reagent primary ions with H.sub.2SO.sub.4 molecules in said interaction region in order to arrange interaction between the reagent primary ions and the H.sub.2SO.sub.4 molecules, thereby producing HSO.sub.4.sup. ions and again to produce HSO4.sup. ion clusters comprising HSO.sub.4.sup. ions and at least two H.sub.2SO.sub.4 molecules via interactions of HSO.sub.4.sup. with other H.sub.2SO.sub.4 molecules in said interaction region, and introduce said HSO.sub.4.sup. ion clusters with the sample particles of the sample gas flow in order to provide reactions between said HSO.sub.4.sup. ion clusters and the sample particles, and thereby provide a sample cluster comprising the HSO.sub.4.sup. ion clusters and said base sample to be determined.

12. The device of claim 11, wherein the device is configured to introduce said H.sub.2SO.sub.4 molecules to the sample gas flow before the interaction region in order to provide a mixed sample gas flow to be introduced to said interaction region.

13. The device of claim 12, wherein the introducing member is a saturator, and wherein the device is configured to use carrier medium for carrying said H.sub.2SO.sub.4 molecules to said interaction region.

14. The device of claim 13, wherein the saturator is configured for producing H.sub.2SO.sub.4 molecules by manipulating SO.sub.2+H.sub.2O solution with a radiation source.

15. The device of claim 13, wherein the saturator comprises a rotating means immersed at least partially into H.sub.2SO.sub.4 fluid and configured to transfer H.sub.2SO.sub.4 from the saturator and thereby to saturate the carrier medium with H.sub.2SO.sub.4 when said carrier medium is flown through the saturator.

16. The device of claim 11, wherein the device comprises an X-ray radiation or -radiation source or a corona discharge source as a generator for producing said reagent primary ions.

17. The device of claim 11, wherein the device comprises a second flow tube for producing a sheath flow to flow at least through a primary ion production region or said interaction region between the sample gas flow and inner wall structure of the device.

18. The device of claim 11, wherein the device is configured to bend the trajectory of the produced reagent primary ions inward and towards the mixed sample gas flow or H.sub.2SO.sub.4 molecules by an electrode or a flow current guiding member comprising a deflector, wing or throttle.

19. An arrangement comprising a detector and a device for ionizing sample particles of a sample gas flow, wherein the particles comprise base molecules or clusters, and wherein the device comprises: a first flow tube for providing the sample gas flow, introducing member for providing H.sub.2SO.sub.4 molecules to an interaction region, a generator selected from the group consisting of X-ray radiation source, -radiation source, -radiation source, and a corona discharge source for producing reagent primary ions from particles of candidate reagent gas flow essentially in a primary ion production region, wherein said device is configured to: introduce said reagent primary ions with H.sub.2SO.sub.4 molecules in said interaction region in order to arrange interaction between the reagent primary ions and the H.sub.2SO.sub.4 molecules, thereby producing HSO.sub.4.sup. ions and again to produce HSO4.sup. ion clusters comprising HSO.sub.4.sup. ions and at least two H2SO4 molecules via interactions of HSO.sub.4.sup. with other H.sub.2SO.sub.4 molecules in said interaction region, and introduce said HSO.sub.4.sup. ion clusters with the sample particles of the sample gas flow in order to provide reactions between said HSO.sub.4.sup. ion clusters and the sample particles, and thereby provide a sample cluster comprising the HSO.sub.4.sup. ion clusters and said base sample to be determined and wherein said sample cluster comprising the HSO.sub.4.sup. ion clusters and said base sample produced by said device is introduced to said detector for determination.

20. The arrangement of claim 19, wherein said detector is an APi-TOF mass spectrometer quadrupole MS, ion trap MS, or ion mobility analyser.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Next the invention will be described in greater detail with reference to exemplary embodiments in accordance with the accompanying drawings, in which:

(2) FIG. 1 illustrates a principle of an exemplary device for ionizing particles of a sample gas flow according to an advantageous embodiment of the invention.

DETAILED DESCRIPTION

(3) FIG. 1 is a principle-level schematic illustration of both a method and a device 100 for ionizing particles of a sample gas flow according to an advantageous embodiment of the invention. The device 100 comprises an inlet, which can be in the form of a first flow tube 102 for providing the sample gas flow 101. In addition the device comprises a generator 104 for producing reagent primary ions 103a from particles of candidate reagent gas flow 103 essentially in a primary ion production region 112 (region where the ionizing radiation ionizes the candidate reagent gas flow 103). The generator 104 may be an X-ray radiation or -radiation source or a corona discharge source, as an example. These are only examples and also other types of sources can be used, such as -radiation source.

(4) In addition the device comprises also providing means 116 for providing and introducing H2SO4 molecules, preferably vapour, 114a to an interaction region 113. The H2SO4 providing means is advantageously a saturator 116, but also other types of providing means can be applied, such as a device with a space for SO2+H2O solution with a radiation source, such as UV radiation source to produce H2SO4 vapour. A carrier medium 117, such as N2 flow, is advantageously used for carrying 118a, 118b said H2SO4 molecules to the interaction region 113.

(5) According to an example the saturator 116 as the providing means comprises a rotating means 116a, which is immersed at least partially into H2SO4 medium 114b. The rotating means advantageously rotates and thereby introduce fresh H2SO4 medium for the carrier medium 117 and thereby saturates the carrier medium 117 with H2SO4 when said carrier medium is flown 118a, 118b through the saturator.

(6) It is to be noted that said H2SO4 molecules 114a can be introduced by the providing means 116 to the sample gas flow 101 before the interaction region 113 in order to provide a mixed sample comprising said H2SO4 vapour and the particles, such as ammonia or amines, to be determined (as is described in FIG. 1), whereupon the gas flow with said H2SO4 vapour and the particles are introduced to the interaction region 113.

(7) The device is configured to introduce said reagent primary ions with H2SO4 molecules 114a in said interaction region 113 in order to arrange interaction between the reagent primary ions 103a and the H2SO4 molecules 114a, thereby producing HSO4.sup. ions and again to produce HSO4.sup. ion clusters comprising HSO4.sup. ions and at least two H2SO4 molecules (i.e. H2SO4.H2SO4.HSO4 or H2SO4.H2SO4.H2SO4.H2SO4 etc. . . . ) via interactions of HSO4.sup. with other H2SO4 molecules in said interaction region 113.

(8) In addition, the device may comprise also a laminarizer 108 for producing an essentially laminar sheath flow 103b between the reagent primary ions flow 107 and structure 119 of the device 100 and/or said second tube 109 in order to prevent or minimize the interaction between the structure of the device and the produced reagent primary ion flow.

(9) It is to be noted, that according to an embodiment the device may additionally comprise a second flow tube 109 for producing a sheath flow 103b to flow at least through a primary ion production region 112 and/or said interaction region 113 between the sample gas flow 101 and inner wall structure 119 of the device, and thereby preventing or at least minimizing any interactions of the sample and/or reagent ions flow with the wall structure 119 of the ionizer 100. The first 102 and second 109 tubes may advantageously be arranged essentially concentrically in order to arrange said sample gas flow and candidate reagent gas flow to flow essentially concentrically at the primary ion production region. The sheath flow is advantageously essentially laminar flow, and it comprises e.g. clean air or nitrogen, with small amounts of reagent gas molecules, e.g. nitric acid, sulphuric acid, acetic acid methyl iodide or oxygen.

(10) The device is advantageously also configured to bend the trajectory 107 of the produced reagent primary ions 103a inward and towards the mixed sample gas flow and/or H2SO4 molecules 114a by the means of electric field 106 produced by suitable electrodes and/or a flow current guiding means, such as a deflector, wing or throttle, like a venturi tube (not shown). According to an embodiment the electrode may be a separate electrode or it may be implemented via the second flow tube 109, which may comprise at least portion of it to function as an electrode and generating an electric field 106 and is thereby configured to bend the trajectory 107 of the produced reagent primary ions inward and towards the sample gas flow 101.

(11) The device 100 as it simplest does not necessary comprise any detecting means 120. Anyhow, in order to also detect the samples ionized by the device 100, the device may be provided with a suitable detector, such as APi-TOF mass spectrometer quadrupole MS, ion trap MS, or ion mobility analyser, for example.

(12) The device may also comprise a shielded area 105 between the X-ray or other radiation source 104 and the flowing media 103 (such as candidate reagent gas flow 103 and sheath flow 103a) for shielding the radiation source about any possible contamination of sample or other particles presented in the flow tubes. The shielded area 105 comprises advantageously beryllium, aluminum or glass, when the radiation source 104 is the X-ray source.

(13) In addition the device may comprise also a laminarizer 108 for producing an essentially laminar sheath flow 103a between the reagent primary ions flow 107 and structure 115 of the device 100 and/or said second tube 109 in order to prevent or minimize the interaction between the structure of the device and the produced reagent primary ion flow.

(14) Moreover, the device may comprise also an outlet channel 110 at the downstream portion of the device for removing the excess flow before the detector to be coupled with the device. The device may also comprise an adjusting means (not shown) for adjusting the flow rates of sample gas flow, candidate reagent gas flow and/or the sheath flow; as well as adjusting means for adjusting the current and/or voltage of the used X-ray source.

(15) The invention has been explained above with reference to the aforementioned embodiments, and several advantages of the invention have been demonstrated. It is clear that the invention is not only restricted to these embodiments, but comprises all possible embodiments within the spirit and scope of the inventive thought and the following patent claims.