VALVE AND ITS USE

The invention concerns a valve after the generic term of the patent claim 1 and its use.

Gas chromatography mass spectrometry (GC-MS) developed to a matured, high-complex method of trace analytics. In each analysis laboratory, which accomplishes for example proof of chlorinated aromatics or dioxins, GC-MS is used. However the conventional GC-MS pushes now to the borders of its development possibilities; these concern above all speed and chemical sample preparation. For a highly sensitive, highly selective capillary office ms analysis, e.g. of chlorine dioxin isomers, the chemical sample preparation (clean UP) can last up to several days. Apart from the personnel expenditure this means above all a large expenditure of time, that in many cases is not acceptable (emergency, on-line monitoring of majority combustion plants, production-integrated environmental protection according to BMFT action 1994). But even the office ms run in the Ultraspurenanalytik can take one hour and longer and know even then interference (e.g. of Pentachlor Biphenylen and Tetrachlor dioxins) in the office ms spectrum to arise. Complex “Clean UP” and heavy, but nevertheless highly precisely adjusted magnets makes besides conventional capillary OFFICE ms for mobile analytics uselessly. In the last 15 years from there new ways followed, whereby either the mass spectrometry was replaced by other selective checking methods, primarily by UV spectroscopy it was resulted, new methods of the mass spectrometry introduced or three-dimensional methods from combination of office, UV spectroscopy and mass spectrometry. Increase of the speed and/or avoidance or decrease of the expenditure for the “Clean UP” was in most cases the goal.

State of the art:

Effusiver gas inlet: In early attempts the end of the office capillary was used as continuous effusiver gas inlet into a vacuum, or also into a gas cell, like for example a kind proportional counter /1/. The ions are produced here by resonance-strengthened multi-photon ionization (REMPI) /2/ (see Figur1). Since the first photon is absorbed molecule-specifically due to its wavelength, this ionization method is very selective (Figur1). The UV spectroscopy is also included as it were into the ionization process. Another working group /3/ let the office capillary end directly in the ion gun of a flying time mass spectrometer, whereby they used a Excimerlaser for the ionization, not tunable in the wavelength. In principle this arrangement - effusiver inlet in ion guns of flying time mass analyzers - is suitable also for REMPI /4, 5,6/.

Disadvantage of a effusiven gas inlet is the reduced selectivity of the UV spectroscopy, there even at room temperature by thermal suggestion of oscillations and rotations the spectra of larger molecules (e.g. .PAH's) of strong gang overlay up to the Strukturlosigkeit are coined/shaped.

Continuous supersonic ray: Already early one stated that in a supersonic ray of a feed gas (e.g. noble gas) with little per cent portion of a molecule, this can be cooled on very low temperatures, without it can condense /6/. For the UV spectroscopy of larger molecules this crucial new impulses supplied. In addition, the advantages of this new spectroscopy for analytics soon recognized /7/. Thus the gas of an office capillary at its end was eased by 150 mu m a far nozzle in the vacuum, registered with a wavelengthtunable laser lively and induced fluorescence. Due to the molecule cooling this suggestion spectroscopy was now particularly selective /8/.In special “sheath flow” - arrangement, in which the actual supersonic ray is refokussiert by a kind coat gas, could be still substantially increased sensitivity (200-20ng) /9/. Used in a further arrangement with other objective the continuous supersonic ray from an office capillary for the separation from feed gas and the molecules which can be specified (different spatial behavior) around then with not-selective ionization methods and quadrupole mass spectrometers to prove /10/. Disadvantages of continuous supersonic rays are either high Gasanfall and thus high requirements to the evacuated system or back pressure into the capillary with reduction of the dissolution of office above all however lead a continuous gas inlet combined with a pulsed ionization method - like REMPI - to an unfavorable relationship from sample gas pulse length to ionization pulse length, and thus to Einbuss in sensitivity.

Pulsed supersonic rays: Finally pulsed valves were inserted for the production by supersonic rays, in order the office coupling to pulsed ion guns, e.g. ionization with pulsed lasers, to adapt and to pulsed ICR loading /11/, on with pulsed lasers induced fluorescence proof /12/ or to a flying time mass spectrometer /13, 14/. Particularly the heatableness of the valves and thus the adjustment represents to the temperature of the office column often a problem. Three different kinds of the coupling of the office capillary to the pulsed valve crystallized so far. (A) Linking into the usual feed gas inlet of the pulsed supersonic ray valve /13/ (see Figur2A). Here the gas must along-touch over narrow long gaps between mobile tappet and its guidance, until it arrives at the periodically opened nozzle. Sand-caught the office pulse extremely largely (bad dissolution of office), the cooling of the molecules is however quite well, sensitivity reduced (mu g, proclaims 3 100 ng). The gas pulses dismissed in the vacuum were relatively long with 1,3 ms /13/ (sensitivity reduced). (B) The office gas is let in continuously into a very small pre-chamber, which is flooded periodically by a pulsed valve with noble gas. From leaking out over a nozzle hole of the pre-chamber a Überscahllstrahl /12/ results (see Figur2B). Sanding of the office pulses is reduced, the gas pulses dismissed in the vacuum has however a length of 50 ms, which equals a continuous gas inlet with an enterprise with 20 cycles per second nearly. Aussderdem is clearly reduced the cooling. Sensitivities of 6-2ng are indicated. (C) The office gas let in on half height of the mobile tappet /14/ (see Figur2C). The largest part is led forward across the usual noble gas supply to the rear, a small part to the periodically opened nozzle. This arrangement was selected, in order to be able to work also with liquids and supercritical gases (LC, HPLC). The same problems as during arrangement (A) result also here. Aussderdem a bad cooling was observed. Arrangement (A) and (C) lead also to problems of the heating, since the entire valve (e.g. also Solenoid) must be held up-high temperatures, but because of verwinkelter gas ways nevertheless cold places and thus condensation of the measuring substances to be not completely avoided can. In addition the efficiency of the valve drive (e.g. a Solenoids) can be reduced or endangered by high temperatures.

Goals of the available invention:

For these reasons a new pulsed valve for the coupling of Eluenten by gas chromatography or continuous gas flows with a supersonic ray was developed. The following goals, which could not be achieved so far for pulsed valves together with office coupling not at all or, were determining for this development: as small temporal a sanding of the office peaks for high office selectivity or the temporal changes of concentration of the Analyte in continuous gas flows as possible.

This reached by minimized dead volumes and avoidance of gas ways by close and long columns. In addition above all requirement serves 1.2 and 4. in addition is to ensure the requirements 3.4 and 6 an optimal adjustment to further office parameters. if possible shortens supersonic ray gas pulses for high sensitivity.

Short gas pulses permit a favorable relationship of gas pulse duration and ionization pulse duration; this is particularly important for ionization with short laser pulses. Short sample gas pulses are reached by the scarce building method according to requirement 1 and 2. Avoidance of dilution effects by Zusatzgase for high sensitivity. as good a cooling of the molecules in the supersonic ray for high selectivity of spectroscopy or REMPI as possible.

Short gas pulses and high pressure gradient make an optimal cooling possible. Also apart from the scarce building method this becomes by optimization of the valve opening time (requirement 7) with consideration of the office conditions (requirement 6) reached. as good thermal an uncoupling of the valve drive of nozzle hole and office inlet for avoidance of cold places as possible (MEMORY effects!) or disturbance of the valve drive. Multi-component ability during a Gaschromatogramms for fast Screening - examining select sentences of trace substances or typical representatives of groups of substances. This is to be achieved by the characteristics of the secondary claim.

This task is solved by the characteristics of the patent claims 1 and 8. the Unteransprüche to describe favourable arrangements of the invention.

This concerns a valve, into which a gas chromatography (office) - capillary flows, which serves the production of a molecular supersonic ray into a Vakuumgefäss, whereby a coupling the office at secondary trace element analysis devices, in particular mass spectrometers, fluorescence cells and ionization measuring cells, is realized, a Ventilkopf with the end of a mobile tappet and a cap with nozzle hole contains. The point of the tappet 1 is in such a way formed that it can open and close the nozzle hole periodically that it at the same time opens the way between nozzle hole and point of the office capillary column 6 during the opening phase, and that it is sealed against the remainder of the tappet and the valve interior. The end of the office capillary is in such a way led that it directly to the tappet point near-been enough and that it is sealed against the interior between tappet guidance 2 and cap 3, as well as between tappet guidance 2 and tappet 1, such that the dead volume between and around office capillary column end, tappet point and nozzle hole is as small as possible. The Ventilkopf, consisting of capillary column end of 6, tappet end of 1, nozzle hole 7 and surrounding seals 4.5.8, guidance and mounting plates is heatable on temperatures suitable for the office enterprise. For the training of a pulsed supersonic ray only the feed gas from the office capillary column and no additional feed gas are used. The thermal uncoupling of Ventilkopf and valve drive, importantly for a troublefree enterprise of the Solenoid or Piezoantrieb, is reached by spatial separation and selective heating of the Ventilkopfes and cooling of the valve drive. The middle opening time - pulse length x Öfffnungsfrequenz - of the valve is co-ordinated aufden gas flow the office. Opening time and pressure gradients between valve inside and Vakuumgefäss are in such a way optimized that an effective molecular cooling in the supersonic ray is reached and so hochaulösende UV spectroscopy and concomitantly highly soluble resonant multi-photon ionization (REMPI) is possible. The geometrical extents, in particular the diameter of the Ventilkopfes, are to be integrated small enough around it into the ion optics of a flying time mass spectrometer. A valve, combined with resonant multi-photon ionization can be in such a way operated the fact that, by pulsed suggestion sources of light, in particular lasers, with several very fast switchable wavelengths and high pulse repetition rate light into the office supersonic ray is linked such that with particulars, select wavelengths selectively a substance or a substance class becomes lively that for each of these wavelengths its own, time-shifted flying time mass spectrum is taken up and that within an office spectrum or even individual office peak between these wavelengths is switched.

Description of a remark example:

In figure 3a an execution form of the Ventilkopfes is represented after above patent claims. The entire valve including valve drive is shown in figure 3b. The Ventilkopf consists of a cap 3, which guidance part of 2 for the mobile tappet 1, which is linking (poetry) 9 for the office column 6th cap 3 and guidance part of 2 with one another bolted. The drilling in the guidance part of 2 in that the tappet 1 is led, is on fit to the tappet 1 manufactured around a surface poetry of the valve head area against the valve impulse 11 to be realized. A further sealing effect is reached by the insert 4. Centrically in the ground of the cap 3 a becherförmige lowering with a diameter of 0.3-1.2 mm and a depth of approx. 1 mm is on the high pressure side. The conical point of the tappet 1, those from different materials to be manufactured can (e.g. Vespel, Aluminum, brass, teflon) seals against the upper edge of the becherförmigen lowering (edge poetry). Alternatively the edge of the becherförmigen lowering can be conical lowered, in order to make a surface poetry possible with the tappet. In the ground of the becherförmigen lowering is the nozzle hole 7 with e.g. 0.1 mm up to 0.8 mm in diameter and 0.1 to 1 mm of length. The volume of the becherförmigen lowering is coupled over this nozzle hole 7 to the vacuum side. In the case of a rise of the tappet 1 the becherförmige lowering is geoffnet to the high pressure side. Thus a part of the Gasprobe continuously flowing by the valve is eased by the nozzle hole 7 into the vacuum and thus a supersonic ray (jet) is trained. In the feed gas solved molecules are strongly cooled in their rotation and oscillatory movements. In the enterprise of the valve as Kopplungselement between gas chromatography and e.g. resonant laser ionization in the supersonic molecular beam the valve is operated periodically with as high a Widerholfrequenz as possible of e.g. 20 cycles per second. With Solenoid drives of the tappet can be obtained opening time between 100 and 200 mu s. Between the guidance part of 2 of the tappet and the ground of the cap 3 out e.g. is a disk-shaped insert 4. Vespel, steel, teflon or glass. Into its ground radially a groove is eingefrässt, whose internal dimensions correspond exactly to the external dimensions of the capillary column. In addition this Vespeleinlage 4 serves the capillary column 6 as spacer between 2 and 3, as guidance for the end and as poetry of the capillary column end against the gap between tappets 1 and its guidance 2.Das end of the capillary column 6 is sealed by a micro poetry from graphite 8 and screw-type cap 9 against the vacuum. The arrangement of capillary column end, tappet point and central opening in the Vespeleinlage ensures a minimum dead volume before the capillary end, which can empty itself very rapidly over the nozzle hole, if the mobile tappet releases the nozzle hole and the way between nozzle hole and capillary end pulse-like. The relaxing gas is thereby the office feed gas, in which the sample substances are solved and arrive in accordance with their retention times at the capillary column end.

In figure 3b an execution form is shown, in which a spatial separation from Ventilkopf was realized and a solenoid valve drive 11 by an extension of the tappet 1 and its guidance 2. The further process of the tappet 1 in the valve drive 11 is not represented. The Ventilkopf 3 can be heated by the heating 5, in order to avoid a condensing of heavyvolatile substances. If by this heating the temperature of the solenoid valve impulse becomes too high, this can be cooled by a cooling 12. By the separation from Ventilkopf 3 and valve drive 11 an overheating of the valve drive 11 and associated malfunctionings are avoided. Such a office coupling with pulsed supersonic ray valve has outstanding characteristics, in particular for the combination with resonant multi-photon ionization (REMPI) and Flugzeitmassenspektrometrie.Das minimum dead volumes and the avoidance of gas diffusion in long, thin channels, e.g. between tappets and tappet guidance, prevent both a sanding of the office pulses as well as MEMORY effects. The feed of the Office-Efluents still on the high pressure side of the valve and the use of the office feed gas as feed gas of the Überscahllstrahles leads outstanding cooling of the internal molecular freedom of movement degrees. The short gas pulses permit the collection of a high office gas portion by pulsed ionization methods.

In the figure 3c an execution form of the Ventilkopfes is represented for linking a continuously fed Gasprobe (e.g. for an on-line measurement of emissions). The Ventilkopf consists 8 for the office column 6 of a cap 3a, the guidance part of 2 for the mobile tappet 1, linking 9 and poetry and that linking 9a and poetry 8a for the sample derivative 6a (e.g. on basis of an office column or a steel capillary). Is the drilling in the guidance part of 2 in that the tappet 1 led, is on fit to the tappet 1 manufactured around a surface poetry of the valve head area against the valve impulse 11zu realize. A further sealing effect is reached by the insert 4. On the sample derivative 6a an external vacuum can be set can around the sample gas by the valve pull. Cap 3 and guidance part of 2 are bolted with one another; with a sealing ring the inside of the valve is sealed against the vacuum. Centrically in the ground of the cap 3a a becherförmige lowering with a diameter of 0.3-1.2 mm and a depth of approx. 1 mm is on the high pressure side. The conical point of the tappet 1, those from different materials to be manufactured can (e.g. Vespel, Aluminum, brass, teflon) seals against the upper edge of the becherförmigen lowering (edge poetry). Alternatively the edge of the becherförmigen lowering can be conical lowered, in order to make a surface poetry possible with the tappet. In the ground of the becherförmigen lowering is the nozzle hole 7 with e.g. 0.1 mm up to 0.8 mm in diameter and 0.1 to 1 mm of length. The volume of the becherförmigen lowering is coupled over this nozzle hole 7 to the vacuum side. In the case of a rise of the tappet 1 the becherförmige lowering is periodically geoffnet to the high pressure side. Thus a part of the Gasprobe continuously flowing by the valve is eased by the nozzle hole 7 into the vacuum and thus a supersonic ray (jet) is trained. In the gas solved molecules are strongly cooled in their rotation and oscillatory movements. With Solenoid drives of the tappet can be obtained opening time in the 10 mu s range. Between the guidance part of 2 of the tappet and the ground of the valve cap 3a a disk-shaped insert 4. this insert 4 is can e.g. from Vespel, teflon, high-grade steel, ceramic(s) or quartz glass be manufactured. Into its ground radially a groove is eingefrässt, whose internal dimensions correspond exactly to the external dimensions of the capillary column. This insert 4 serves 3a and the guidance part of 2 of the tappet (for the realization of a minimum dead volume) for filling out the volume between valve cap in addition, as guidance for the end of the capillary column 6 and as poetry of the capillary column end against the gap between tappets 1 and its guidance 2. the end of the capillary column 6 is sealed by a micro poetry from graphite 8 and screw-type cap 9 against the vacuum. The small spatial distance between capillary column end, tappet point and central opening in the insert 4 ensures itself a minimum dead volume of approx. 1 mm<3> before the capillary end, very rapidly over that Nozzle hole to empty can, if the mobile tappet releases the nozzle hole and the way between nozzle hole and capillary end pulse-like. The valve type shown in the figure 3c is to be made possible besoders suitably around a continuous transfer of sample gas into pulsed supersonicmolecular-stolen. By the sample departure 6a a high, unimpaired flow rate in the capillaries 6 and 6a becomes (e.g. mehere meters per second) and realized in the valve. This has the following Vorteiele: 1) of the valve opening time unbeinflusster sample taking river 2) with high Zeitauflösung 3) minimization of chemical MEMORY effects further can in the figure 3c valve shown also for linking the Eluenten of a gas chromatograph be used. The gas relaxing by the nozzle 7 is thereby the office feed gas, in which the sample substances are solved and arrive in accordance with their retention times at the capillary column end. Hiebei exists now additionally for figure 3a and figure 3b the possibility flowing off the Eluenten with a secondary keep in track-analytic detector (e.g. flame ionization detector (FID), over the capillary the 6a, or elctron capture detector (ECD)) to analyze.

In figure 4 the execution form of a complete system is shown, in which the pulsed office supersonic ray valve is used after figure 3 for the coupling of office, REMPI and flying time mass spectrometry. Over a gas chromatograph and a heatable inlet the valve with office feed gas is fed. This relaxes in a Vorvakuumsystem under cooling of the internal degrees of freedom of the sample molecules loosened in it. A Skimmer serves as pressure reducing stage and for the education of a narrow, pulsed molecular jet. This crosses the ion gun, consisting of axially attached screens with central holes for the departure of ions. These are formed species-selectively by resonant multi-photon ionization (REMPI), taken off transverse to the molecular beam with a static electrical field and proven in an Reflektron Flugzeitmassen analyzer.

With this equipment the following tests of the office supersonic ray pulse valve were accomplished: For wavelength spectra a gas was continuously let in and the signal intensity of a mass as function of the laser wavelength was measured; for flying time mass spectra to a certain retention time and for one or averaged over some few laser pulses one measured; for Gaschromatogramme with a mass or an select sentence by masses and a selective wavelength, a halfselective wavelength or unselektiver laser-induced electron ionization one measured. In figure 5 the wavelength spectrum of a vibronischen gang of benzene is represented. From the comparison of the experimental form and a theoretical gang form, which can be simulated for different temperatures, the so-called rotation temperature results after the supersonic ray cooling. Figure 5 shows the outstanding molecular cooling of the valve. It is Vorraussetzung, in order to really achieve the high selectivity, which is possible with REMPI.

In figure 6the Gaschromatogramm of a Berzinkraftstoffes is shown, which was synchronously taken up with the office supersonic ray valve, for aromatics specific, but under aromatics unselektiven laser wavelength and with four masses. With the mass 106 are it shown in the Gaschromatorgramm Ethylbenzol, meta, ortho and para xylene. Meta and para xylene from the assigned column were not separated. A sanding of the office pulses is practically not recognizable. This is shown by figure 6b. Here the group of molecules of the mass 106 is proven once over conventional gas chromatography, and once over Office-supersonic ray-REMPI with a Laserwelllenlänge by 266 Nm, like in figure 6a. In both cases a capillary with identical parameters was used.

In figure 7 and 8 is to be demonstrated, as by means of the combination of the office supersonic ray valve with REMPI the problem of missing isomer selectivity the office - see figure 6: meta and para xylene - without chemical Vortrennung to be solved can. In addition the laser light source was co-ordinated by 266nm (unselektiv, figure 6a) with 272,3 Nm. With this wavelength now only para xylene becomes most selectively lively under the mentioned four isomers molecules of the mass 106. This the rem pi wavelength spectra in figure 7. these spectra occupy owe their spectral sharpness and thus selectivity of the molecular cooling in the supersonic ray. Without this cooling such a isomer separation would be absolutely not possible. Similarly selective spectra could be shown for example for dichlorierte dioxins and Biphenyle or all several times chlorinated benzene /15/.

In figure 8 again a Gaschromatogramm with aromatic-now-selective rem pi proof is above pointed during a reading reading of 266nm to the comparison (cutout from Figur6). In figure 8 down is now a Gaschromatogramm of the same sample (cutout of the office retention time), but with para xylene selective proof with the laser wavelength of 272,3 Nm. The high selectivity only for para xylene is to be determined clearly. In figure 9 sensitivity was finally tested. For 500 fG toluol amounted to intoxication relationship still 6. an optimization of the ionization efficiency, which was not accomplished so far yet, can still to a Verbessserung around at least one order of magnitude lead. Thus also the sensitivity range of conventional highly soluble capillary office ms devices is reached.

The office supersonic pulse valve introduced here opens the possibilities, which result in principle from the combination of gas chromatography, highly soluble UV suggestion and mass spectrometry opposite conventional GC-MS. These possibilities are: new highly selective three-dimensional trace analytics: Three measuring parameters retention time (office), UV wavelength (REMPI) and mass (flying time mass spectrometry) come synchronously to the effect. a strong reduction of the Clean UP expenditure: One can do without an extremely high selectivity of the gas chromatography, since the missing selectivity is made by the UV spectroscopy. substantially faster analytics with similar selectivity and sensitivity as with conventional GC/MS Gerätzen. a fast Screening during only one office run. mobiles and nevertheless highly soluble Ultraspuren analyzer.

In contrast to it assigned pulse valves with problems are such as reduction of the dissolution of office, which UV dissolution or sensitivity afflicted, which limited or even prevented the realization of the possibilities so far strongly.

Quotations:

/1/ gas chromatography with detection by lasers excited resonance enhanced 2-photon photoionization; C.M.Klimcak, J.E.Wessel, Anal. Chem. 52, (1980) 1233. /2/ a) multi-photon excitation and measure selective ion detection for neutrally and ion spectroscopy; U.Boesl, J. physical one chem. one 95 (1991) 2949. b) Two photon ionization OF polyatomic molecules in A measured more spectrometer; U.Boesl, H.J.Neusser, E.W. Impact, Z.Naturforsch. 33A (1978) 1546. c) Resonance enhanced multi-photon ionization: A species selective ion SOURCE for analytical time OF flight measured spectrometry; U.Boesl, R.Zimmermann, C.Weickhardt, D.Lenoir, K. - W.Schramm, A.Kettrup, E.W.Schlag, Chemosphere 29 (1994) 1429. /3/ a) Ionization OF of alkyl benzene studied by gas chromatography/lasers ionization measured spectrometry; R.B.Opsal, J.P.Reilly, Anal.Chem. 60, (1988) 1060; b) Analysis OF polyaromatic hydraulic carbon mixtures with laser ionization gas chromatography/measured spectroemtry; G.Rhodes, R.B.Opsal, J.T.Meek, J.P.Reilly, Anal. Chem. 55, (1983) 280; c) Chromatographic effluent detection with lasers ionization measured spectrometry R.B.Opsal, J.P.Reilly, Optics news June (1986) 18. /4/ multi-dimensionally, laser based instrument for the characterization OF environmental samples for polycyclic flavour TIC compounds; R.L.M.Dobson, A.P.D'Silva, S.J.Weeks, V.A.Fassel, Anal.Chem. 58, (1986) 2129. /5/ a) Reflectron time OF flight measured spectrometry and laser excitation for the analysis OF neutrals, ionized molecules and secondary fragment; U.Boesl, R.Weinkauf, E.W.Schlag, Int. J. Measure spectrom. Ion Proc. 112 (1992) 121. b) laser ion SOURCEs for time OF flight measured spectrometry; U.Boesl, R.Weinkauf, C.Weickhardt, E.W.Schlag, Int. J.Mass Spectrom. Ion Proc. 131 (1994) 87. /6/ ion gun: E.W.Schlag, H.J.Neusser, U.Boesl German patent 1983, No. 2,942,386 /7/ Analytical spectroscopy in supersonic expansion; J.M.Hayes, chem. Rev. 87, (1987) 745. /8/ Rotationally cooled laser induced fluorescence/gas chromatography; J.M.Hayes, G.J.Small, 54, (1982) 1204. /9/ Supersonic jet spectroscopy with A capillary gas chromatographic inlet; S.W.Stiller, M.V.Johnston, Anal. Chem. 59, (1987) 567. /10/ nearly, high temperature and thermalunstable GC-MS in supersonic molecular beams; S.Dagan, A.Amirav, Int. J. Spectrom measured. Ion Proc. 133, (1994) 187. /11/ gas chromatography/multiphoton ionization more fourier transform measured spektrometry; T.M.Sack, D.A.McCrery, M.L.Gross, Anal.Chem. 57, (1985) 1290. /12/ a) Capillary gas chromatography/pulsed supersonic jet/fluorescence excitation spectroscopy for the identification OF of methylanthracenes in A complex environmental SAM-polarizes; B.V.Pepich, J.B.Callis, D.H.Burns, M.Gouterman, D.A.Kalman, Anal. Chem. 58, (1986) 2825; b) Pulsed free jet expansion system for high resolution fluorescence spectroscopy OF capillary gas chromatographic effluents; B.V.Peppich, J.B.Callis, J.D.Sh. Danielson, M. Gouterman, Rev, Sci. Instrument. 57, (1986) 878. /13/ a) High temperature pulsed nozzle for supersonic jet spectrometry and its application ton gas chromatography; T.Imasaka, T.Okamura, N.Ishibashi, Anal.Chem. 58, (1986) 2152; b) Hyphenated of techniques in supersonic jet spectroscopy and its analytical applications tons of flavour TIC of hydraulic carbon; N.Ishibashi, T.Imasaka, Analytical Sciences 7 Suppl., (1991) 489; c) Supersonic jet spectrometry and its application tons chromatograph detectors T.Imasaka, Spectrochimica Acta 14, (1991) 261. /14/ A high pressure pulsed expansion valve for gas, liquids, and supercritical fluid C.Köster, J.Grotemeyer, E.W.Schlag, Z.Naturforsch 46a, (1990) 1285 /15/ a) laser measured spectrometry OF dibenzodioxin, dibenzofuran and two isomer OF dichlorodibenzodioxins: selective ionization; C.Weickhardt, R.Zimmermann, U.Boesl, E.W.Schlag, rapidly COMM measure of Spectrom. 7 (1993) 183. b) isomer selective ionization OF chlorinated aromatics with laser for analytical time OF flight measured spectrometry; R.Zimmermann, U.Boesl, C.Weickhardt, D.Lenoir, K. - W.Schramm.A.Kettrup, E.W.Schlag, Chemosphere 29 (1994) 1877.

DESIGNS FOR PATENT APPLICATION:

Valve and its use

Ulrich Boesl, Ralf Carpenter, Antonius Kettrup

Figur1 pattern of the resonance-strengthened multi-photon ionization (REMPI). Only if the wavelength of the first photon is in resonance with a specific molecule absorption band, this molecule can become lively and absorb a further photon the ionization: Selective ionization! Figur2 three different couplings of an office column with a pulsed gas valve for supersonic rays, the state of the art for pulsed office supersonic ray valves representing. Figur3a execution form of an office supersonic ray pulse valve, according to the invention. The Ventilkopf Figur3b execution form of an office supersonic ray pulse valve is represented, according to the invention. The total valve with Ventilkopf and valve drive is represented. Figur3c execution form of a supersonic ray pulse valve with Gaszufuhr and gas removal, according to invention-represented is the Ventilkopf. Figur4 execution form of a complete system to the three-dimensional office laser ms analysis, whereby the coupling is reached by means of the office supersonic ray valve. Figur5 wavelength spectrum of a vibronischen oscillation gang of the benzene, after cooling in a supersonic ray, which is produced by a valve in accordance with Figur3. The comparison with simulated absorption bands (e.g. for 2, 5, 15, 50 K) an experimental “rotation temperature” results in Figur6a Gaschromatogramm proven by 15 K., with REMPI and flying time mass spectrometer (TOF for time OF flight). The REMPI wavelength (266 Nm) was selected that as group are selectively proven to aromatics, not however einzelene Aromaten.Es on four masses (92, 106, 120, 134) simultaneously was in such a way proven. Figur6b Gaschromatogramme, proven in a conventional office (above) and with REMPI, flying time mass analyzer and coupling over pulsed valve after Figur3 (down). Office capillaries with identical parameters were used in both cases. Both Gaschromatogramme were measured with the same sample as in figure 6; it correspond there to the group of molecules of M=106, and prove that the pulsed valve leads to no office peak sanding. Figur7 UV absorption spectra of Ethylbenzol, ortho, meta and para xylene. The sharpness of the spectra was reached by cooling in a supersonic ray and is a condition for the selection of one of the four components by laser light. Figur8 above: Gaschromatogramm, proven with REMPI and Flugzeitmassenspektrometer.Die REMPI wavelength amounted to 266 Nm (semiselektiv). The Gaschromatogramm represents a cutout from Figur6 for the retention time from 3 min to 3 min 40 second (group of molecules of M= 106). Down: Gaschromatogramm, proven with REMPI and flying time mass spectrometer with same office conditions, but now a REMPI the Wellenllänge of 272,3 Nm (selective for para xylene). Figur9 example of sensitivity by the example of toluol, reached so far: Optimization through the office supersonic ray pulse valve. An optimization of the ionization yield was not accomplished yet and promises a further sensitivity increase.