US3852037A - Selective ionization detector - Google Patents

Selective ionization detector Download PDF

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Publication number
US3852037A
US3852037A US00357496A US35749673A US3852037A US 3852037 A US3852037 A US 3852037A US 00357496 A US00357496 A US 00357496A US 35749673 A US35749673 A US 35749673A US 3852037 A US3852037 A US 3852037A
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United States
Prior art keywords
alkali
ionization detector
detector
burner nozzle
alkali glass
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Expired - Lifetime
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US00357496A
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English (en)
Inventor
B Kolb
J Bischoff
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PE Manufacturing GmbH
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Bodenseewerk Perkin Elmer and Co GmbH
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Assigned to BODENSEEWERK PERKIN-ELMER GMBH (BSW) reassignment BODENSEEWERK PERKIN-ELMER GMBH (BSW) ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BODENSEEWERK GERATETECHNIK BETEILIGUNGS-UND VERWALTUNGSGESELLSCHAFT MBH
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G01N30/68—Flame ionisation detectors

Definitions

  • This invention relates to a selective ionization detector for halogen, phosphorus or nitrogen compounds, comprising a diode through which a sample gas under analysis can be fed by means of a carrier or transfer gas, and which comprises an electrode including an alkali source in the form of a heated alkali-containing glass so that the electrode exhibits an increased ion emission upon the occurrence of such specific substances.
  • a prior art selective ionization detector of this type which is particularly intended for leak detecting devices or the like includes two coaxially helically wound wires each of which are heatable by means of a filament transformer winding. Between the two wires, which constitute the electrodes of a diode, a d.c. voltage source is connected in series with a measuring device. The innermost wire is wound onto a cylinder of alkali metal glass, for instance, potassium glass. By means of the alkali metal of the glass cylinder a specific sensitizing of the electrode for halogen is effected so that upon passage of halogen-containing gases or vapors between the electrodes a definite increase in the current flowing across the diodes is observed (German patent specification No. 907,223).
  • detectors of the above type are prior art in which an electrode and/or a separate supply of alkali metals are heated by means of a flame. These detectors are formed in the same manner as a flame ionization detector, which detector is conventional in gas chromatography.
  • a burner nozzle is provided to which a combustible gas (for example, hydrogen) and sample gas mixture is supplied, with the sample gas in gas chromatographic detector applications again being a mixture of carrier gas plus eluted sample components.
  • a collecting electrode Above the flame or around the flame there is arranged a collecting electrode. Around the flame an electrode in the form of a spiral is arranged which is coated with a layer of molten alkali salt, preferably sodium sulphate (see U.S. Pat. No. 3,372,994) for sensitizing.
  • alkali salts have been provided in supply vessels of apertured or porous materials so that by diffusion over a longer period of time alkali metal compounds are passed to the surface of these supply vessels (German published patent application No. 1,598,] 18). Although this method ensures an alkali supply for days or weeks, the decrease in the detector sensitivity is still disturbingly high. Moreover, these supply vessels are expensive to manufacture.
  • the basic feature of the invention resides in the fact that the alkali glass is in a viscous or softened state during detector operation.
  • the alkali source therefore consists of glass which softens during operation, whereby it is attained that the surface of the alkali source does not become impoverished as to alkali, since by molecular movement alkali is constantly supplied to the surface.
  • an ionization detector according to this invention differs advantageously from a detector according to the German patent specification No. 907,223 where the alkali cylinder remains in its rigid state and therefore an impoverishment of alkali at the surface soon takes place. Since only very small alkaki quantities are consumed, the supply of a single glassdrop is sufficient for many months. The alkali glass drop may then be readily replaced. No manufacturing costs for monocrystals, supply vessels, or the like are encountered.
  • the detector may be of the form that includes a burner nozzle to which a combustible gas and sample gas mixture are supplied, that above the burner nozzle an alkali glass body is mounted and is heatable by an electric resistance heater to an extent sufficient for softening of the alkali body.
  • the rate of alkali emission very markedly depends on the temperature of the glass.
  • the heating of the alkali glass body is effected electrically and not by the flame, it is not necessary to maintain constant the flame temperature, and therefore the combustible gas (H flow, with the otherwise required accuracy.
  • the gas flows of hydrogen and oxygen can be adapted to the respective temperature requirements, in particular, of the element desired to be detected.
  • the heating of the electric resistance heater is precisely adjustable.
  • provision can be made that independently of the precise adjusting means, a fixed heating capacity sufficient for igniting the flame can be switched on by actuation of a push button or the like.
  • the resistance heater for the alkali glass body is additionally used for igniting the flame.
  • a specificity for particular individual substances can be obtained by a suitable selection of the gas flows and by selection of the appropriate alkali component.
  • rubidium-containing glass it is possible to detect nitrogen compounds; while, for substances of high phosphorus content, sodium-containing glass is selective.
  • An advantageous selective ionization detector of the type indicated above includes a burner nozzle to which a combustible gas and sample gas mixture are supplied; above the burner nozzle an alkali glass body, heatable up to its softening temperature, is mounted; above the alkali glass body a collecting electrode is arranged; and the collecting electrode and nozzle are connected to a positive electric potential with respect to the alkali glass body.
  • ion currents normal flame ionization detector signals
  • CH normal hydrocarbon
  • the electrons from the normal (hydrocarbon) combustion process flow to the burner nozzle, since the mount of the alkali glass body is at a potential negative relative to the nozzle and the electrons cannot overcome this potential.
  • the nozzle and a housing which encloses the nozzle, the alkali glass body, and the collecting electrode are all provided with insulation with respect to ground; a negative voltage is connected to the housing (with respect to ground) and the alkali glass body is electrically connected to the housing, while the collecting electrode is mounted in the housing, but is electrically insulated with respect to the same and is connected to an amplifier at ground, and that the nozzle is electrically connectable alternatively to the housing (i.e., negative) or to ground by means of a switch.
  • the detector can be operated by means of operation ofa simple electric switch alternatively as selective ionization detectoror as normal flame ionization detector.
  • FIG. 1 schematically illustrates the design of a selective ionization detector incorporating the invention
  • FIG. 2 diagrammatically illustrates one possibility of electrical potential distribution in the ionization detector of FIG. 1 in which the latter operates as a flame'ionization detector;
  • FIG. 3 diagrammatically illustrates electrical potential distribution in the ionization detector of FIG. 1 in which the latter operates as an ionization detector selectively responding to phosphorus;
  • FIG. 4 illustrates a chromatogram recorded with the detector in the mode of operation as shown in FIG. 2;
  • FIG. 5 illustrates a chromatogram of the same mixture (on a changed scale) in the mode of operation as shown in FIG. 3, the mixture having a phosphoruscontaining component and a non-phosphoruscontaining component;
  • FIG. 6 illustrates an embodiment of the ionization detector, permitting alternatively a mode of operation according to FIG. 2 or one according to FIG. 3.
  • the detector according to FIG. 1 is substantially in the form of a prior art flame ionization detector (FID).
  • a housing 10 is divided by a partition 12 into a lower and an upper chamber 14, 16, respectively.
  • a burner nozzle 18 protrudes, terminating just below an aperture 20 in the partition 12.
  • a sample gas is supplied to the nozzle 18 via a conduit 22.
  • this conduit 22 is connected with the outlet of a separating column, and the sample gas consists of a mixture of carrier gas plus eluted sample components.
  • a combustible gas generally hydrogen, is added to the sample gas via a conduit 24, so that a combustible gas, sample gas mixture issues from the nozzle and during operation commonly burns with a flame 26. Combustion air is intro Jerusalem into the lower chamber 14 via an air supply conduit 28.
  • a bead 30 of an alkali-rich glass is mounted, specifically by means of two wires 32 and 34 which are passed through the wall of the housing 10 by means of electrical insulators 36, 38. These wires 32 and 34 simultaneously serve as current leads for an electric resistance heating element 40 arranged therebetween and in heatconducting contact with the bead 30.
  • the heating quantity of the electric resistance heating element 40 is precisely adjustable by conventional means not illustrated.
  • a collecting electrode 42 Above the bead 30 is positioned a collecting electrode 42.
  • the collecting electrode 42 is secured to an electrically conducting holder 44, which is passed downwardly through an aperture 46 of the partition 12 and laterally out of the housing 10 by means of an insulator 48.
  • the burnt gases of the flame 26 are exhausted via a connector 50.
  • a suction pump When using the detector as a leak detector a suction pump is connected here.
  • the electric resistance heating element 40 is so constituted that the alkali glass bead 30, when the detector is in operation, can be maintained in a viscous or softened state. In this state, a constant molecular movement and therefore a concentration compensation takes place in the alkali glass bead, so that fresh alkali metal atoms constantly migrate to the surface of the alkali glass bead, and therefore no impoverishment (of alkali metal) occurs.
  • the bracket 52 and/or the wires 32, 34 preferably consist of platinum, on the one hand because platinum has substantially the same coefficient of thermal expansion as glass, and on the other hand due to its chemical inertness.
  • the partition 12 ensures in well-known man ner that the insulator 48 and the conduit lead-out are not impaired (i.e., attacked) by combustion residues.
  • the just described detector is particularly suited for,
  • the sample may be burnt before introduction to the alkali source, which can be effected in a known manner in the first section of a double-level flame ionization detector (FID) or by flameless oxidation.
  • FID flame ionization detector
  • FIGS. 2 and 3 Another possibility of alternatively obtaining a high selectivity is shown by a comparison of FIGS. 2 and 3.
  • FIG. 2 illustrates a circuit in which the normal FlD'signals resulting from the (hydro-carbon) combustion are also obtained.
  • the burner nozzle 18 and the alkali source (softened alkali glass bead 30) are connected to a negative potential with respect to ground by a voltage source 54.
  • the collecting electrode 42 connects to a grounded amplifier 56, thus practically at ground potential.
  • both selective signals for instance, for halogen and phosphorus from the thermionic ion currents which originate from the bead 30, and also normal FID-signals, for instance, from the hydrocarbon components are obtained.
  • the relative sensitivity with respect to halogen and phosphorus is in general increased, however, the detector is not sensitive specifically only to these substances. Such a performance of the detector may be desirable. An increase in the sensitivity is obtained for nitrogencontaining compounds if the flame is operated under reducing conditions.
  • the collecting electrode 42 again connects to the amplifier 56 with respect to ground.
  • the burner nozzle 18 is grounded, and only the alkali glass bead 30 and its mount are maintained at a negative potential (with respect to ground) by the voltage source 54.
  • FIG. 6 illustrates an embodiment which permits the alternative operation according to FIG. 2 or according to FIG. 3 in a simple manner.
  • Corresponding parts are referenced by the same reference numerals as in the FIGS. l to 3.
  • the burner nozzle 18 is insulated with respect to ground by an insulating piece 58.
  • Burner nozzle 18, alkali glass body 30 and collecting electrode 42 are enclosed by a cylindrical housing which is mounted for insulation with respect to ground.
  • the collecting electrode 42 is mounted in this housing 60 by means of an insulator 62.
  • the housing 60 is connected to a negative potential, for instance -l30 volts with respect to ground.
  • switch means 63 the burner nozzle 18 can be alternatively connected electrically to the housing 60 and therewith to the negative potential or to ground.
  • the alkali glass body 30 and its conduits are electrically connected to the housing 60.
  • the detector of the invention described can be used in various manners in order to obtain selectivity for various substances.
  • the glass bead 30 can be formed of sodiumcontaining glass and be excited to alkali emission by electric heating, while the flame 26 burns reducingly (O supplied at 40 ml/min; H at 15 ml/min). Then, a selective phosphorus signal is obtained.
  • a selective nitrogen (N signal can be obtained by corresponding adjustment of the gas flows (0 at 0 ml/min, H at 5 ml/min) when the glass bead 30 is heated electrically. The hydrogen does not operate a flame.
  • the detector can be operated in the following ways:
  • the resistance heating 40 is also used for igniting the flame 26 when operation of the detector is started.
  • a push button switch (not shown) may be provided by which, independently of the precisely effected adjustment of heating quantity (to element 40), a fixed amount of heating can be applied to the resistance heating element 40 which is fully sufficient to ignite the flame 26.
  • a selective ionization detector of the type for detecting halogen, phosphorus and nitrogen compounds comprising a diode through which a sample gas under analysis is fed by means of a transfer gas, and an electrode including an alkali source in the form of a heated alkali-containing glass, so that the electrode exhibits an increased ion emission upon occurrence of such specific substances, the improvement in which:
  • said alkali source comprises alkali glass maintained in a heated softened state during operation of the detector.
  • said alkali glass is a sodium-enriched glass.
  • said alkali glass is a rubidium-enriched glass.
  • a selective ionization detector as claimed in claim 4, in which:
  • a housing (60) encloses said burner nozzle (18); said alkali glass body (30) and said collecting electrode (42) are mounted by means of insulation (58) with respect to ground; said housing (60) is connected to a negative voltage source with respect to ground; said alkali glass body (30) is electrically connected to said housing (60); said collecting electrode (42) is mounted in the housing (60) but is electrically insulated therefrom and is connected to an amplifier (56) which is grounded; and said burner nozzle (18) is electrically connectable alternatively to the housing (60) or to ground by means of a switch means. 6.
  • a selective ionization detector as claimed in claim 1, further comprising:
  • a selective ionization detector as claimed in claim 6, in which:
  • a separate heating quantity sufficient for igniting the flame can be supplied to said heating means by actuation of a manually operated means.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
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US00357496A 1972-05-06 1973-05-04 Selective ionization detector Expired - Lifetime US3852037A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2222396A DE2222396B2 (de) 1972-05-06 1972-05-06 Selektiver lonisationsdetektor

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US3852037A true US3852037A (en) 1974-12-03

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US (1) US3852037A (de)
JP (1) JPS553664B2 (de)
DE (1) DE2222396B2 (de)
GB (1) GB1435747A (de)
NL (1) NL7306217A (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2907222A1 (de) * 1978-02-28 1980-01-10 Varian Associates Verfahren und vorrichtung zur analyse einer probe
US4202666A (en) * 1978-02-24 1980-05-13 Tracor, Inc. Method and apparatus for preventing the destruction of an alkali source of a nitrogen-phosphorous detector
US4361810A (en) * 1980-05-10 1982-11-30 Ratfisch Instrumente Arrangement for monitoring the concentration of potentially explosive substances in gas streams
US4508685A (en) * 1981-06-09 1985-04-02 Carlo Erba Strumentazione S.P.A. Modified-flame thermionic detector for gas chromatographs and method for the identification of components in sample under analysis
US4524047A (en) * 1983-03-02 1985-06-18 Patterson Paul L Thermionic detector with multiple layered ionization source
US4663297A (en) * 1982-09-10 1987-05-05 Yates Jr John T Temperature programmed spectroscopy techniques
US4744954A (en) * 1986-07-11 1988-05-17 Allied-Signal Inc. Amperometric gas sensor containing a solid electrolyte
US4801849A (en) * 1984-05-16 1989-01-31 Office National D Etudes Et De Recherches Ion source operating by surface ionization in particular for providing an ion probe
US4839143A (en) * 1985-02-15 1989-06-13 Allied-Signal Inc. Selective ionization of gas constituents using electrolytic reactions
US4877584A (en) * 1982-09-10 1989-10-31 Yates Jr John T Temperature programmed spectroscopy techniques
US5198009A (en) * 1991-11-22 1993-03-30 The Perkin Elmer Corporation Method of manufacturing glass beads for use in thermionic gas chromatographic detectors
EP0594887A1 (de) * 1992-10-29 1994-05-04 Hans Mueller Prof. Dr. Van Der Haegen Verfahren zur Erkennung von Kunststoffen sowie deren anschliessende Sortierung
US20150330956A1 (en) * 2014-05-16 2015-11-19 Waters Technologies Corporation Flame Ionization Detection Burner Assemblies for Use in Compressible Fluid-Based Chromatography Systems

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5717308Y2 (de) * 1977-04-20 1982-04-12
JPS5717309Y2 (de) * 1977-04-20 1982-04-12
DE2738608C2 (de) * 1977-08-26 1985-02-07 Siemens AG, 1000 Berlin und 8000 München Thermoionischer Detektor für die selektive Bestimmung von organischen, Heteroatome enthaltenden Probensubstanzen
JPS5550155A (en) * 1978-10-06 1980-04-11 Hitachi Ltd Heat ionization detector
JPS56155345U (de) * 1980-04-19 1981-11-19

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372994A (en) * 1965-01-08 1968-03-12 Health Education Welfare Usa Flame ionization detector
US3425806A (en) * 1965-03-22 1969-02-04 Us Health Education & Welfare Method and means for detecting a halogen or phosphorus in a gaseous material
US3589869A (en) * 1969-02-17 1971-06-29 Varian Associates Chemical-ionization detection method and apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372994A (en) * 1965-01-08 1968-03-12 Health Education Welfare Usa Flame ionization detector
US3425806A (en) * 1965-03-22 1969-02-04 Us Health Education & Welfare Method and means for detecting a halogen or phosphorus in a gaseous material
US3589869A (en) * 1969-02-17 1971-06-29 Varian Associates Chemical-ionization detection method and apparatus

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4202666A (en) * 1978-02-24 1980-05-13 Tracor, Inc. Method and apparatus for preventing the destruction of an alkali source of a nitrogen-phosphorous detector
US4203726A (en) * 1978-02-28 1980-05-20 Varian Associates, Inc. Thermionic detector
DE2907222A1 (de) * 1978-02-28 1980-01-10 Varian Associates Verfahren und vorrichtung zur analyse einer probe
US4361810A (en) * 1980-05-10 1982-11-30 Ratfisch Instrumente Arrangement for monitoring the concentration of potentially explosive substances in gas streams
US4508685A (en) * 1981-06-09 1985-04-02 Carlo Erba Strumentazione S.P.A. Modified-flame thermionic detector for gas chromatographs and method for the identification of components in sample under analysis
EP0066735B1 (de) * 1981-06-09 1986-10-29 CARLO ERBA STRUMENTAZIONE S.p.A. Flammenveränderungsionisationsdetektor für Gaschromatographen und Verfahren zur Identifizierung von Bestandteilen in einer zu analysierenden Probe
US4877584A (en) * 1982-09-10 1989-10-31 Yates Jr John T Temperature programmed spectroscopy techniques
US4663297A (en) * 1982-09-10 1987-05-05 Yates Jr John T Temperature programmed spectroscopy techniques
US4524047A (en) * 1983-03-02 1985-06-18 Patterson Paul L Thermionic detector with multiple layered ionization source
US4801849A (en) * 1984-05-16 1989-01-31 Office National D Etudes Et De Recherches Ion source operating by surface ionization in particular for providing an ion probe
US4839143A (en) * 1985-02-15 1989-06-13 Allied-Signal Inc. Selective ionization of gas constituents using electrolytic reactions
US4744954A (en) * 1986-07-11 1988-05-17 Allied-Signal Inc. Amperometric gas sensor containing a solid electrolyte
US5198009A (en) * 1991-11-22 1993-03-30 The Perkin Elmer Corporation Method of manufacturing glass beads for use in thermionic gas chromatographic detectors
DE4237168B4 (de) * 1991-11-22 2006-07-27 The Perkin-Elmer Corp., Norwalk Verfahren zur Herstellung einer alkalimetallhaltigen Glasperle zur Verwendung in thermionischen Gaschromatographie-Detektoren
EP0594887A1 (de) * 1992-10-29 1994-05-04 Hans Mueller Prof. Dr. Van Der Haegen Verfahren zur Erkennung von Kunststoffen sowie deren anschliessende Sortierung
US20150330956A1 (en) * 2014-05-16 2015-11-19 Waters Technologies Corporation Flame Ionization Detection Burner Assemblies for Use in Compressible Fluid-Based Chromatography Systems
US10191020B2 (en) * 2014-05-16 2019-01-29 Waters Technologies Corporation Flame ionization detection burner assemblies for use in compressible fluid-based chromatography systems
US10877006B2 (en) 2014-05-16 2020-12-29 Waters Technologies Corporation Flame ionization detection burner assemblies for use in compressible fluid-based chromatography systems

Also Published As

Publication number Publication date
GB1435747A (en) 1976-05-12
JPS553664B2 (de) 1980-01-26
JPS4949689A (de) 1974-05-14
NL7306217A (de) 1973-11-08
DE2222396B2 (de) 1975-04-30
DE2222396A1 (de) 1973-11-15

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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BODENSEEWERK GERATETECHNIK BETEILIGUNGS-UND VERWALTUNGSGESELLSCHAFT MBH;REEL/FRAME:005305/0545

Effective date: 19891024