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US 4,035,168 AGranted
Nonreactive inlet splitter for gas chromatography and method
AssigneeThe Regents of the University of California
InventorWalter G. Jennings
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AssigneeThe Regents of the University of California
InventorWalter G. Jennings
Estimating the term…
An inlet splitter apparatus and method for introducing substantially unreacted linear aliquots of vaporized sample and carrier gas to the capillary column of a capillary gas chromatograph. An elongate body with separate but axially aligned injector and mixing chambers, an inert (glass) tubular liner interconnecting the separate chambers and having an inlet in the injector chamber and a baffled outlet in the mixing chamber, carrier gas injection means to introduce a stream of carrier gas through an annular passage between the elongate body and tubular liner to an inert core passage in the liner. A sample port and self-sealing septum to facilitate injection of an analysis sample to the inert liner core passage. Heating means (preheater and body heater) to vaporize the sample and pass an intermixed stream of vaporized sample and carrier gas through the inert core passage and baffled outlet of the liner. An expansion zone and metered discharge in the mixing chamber to facilitate a linear split of the sample through the inlet end of a capillary chromatograph column. Optionally, it is preferred to increase the vaporization surface and mixing potential within the tubular liner and injection chamber by means of a packing or filler of very fine (100-120 mesh), inert material (glass beads). The apparatus provides inert (glass) surfaces forming the pathway for the intermixed sample and carrier gas stream so that degradation of the sample by reaction with hot metallic or like surfaces is avoided. Turbulent intermixing within the baffled passageways of wholly inert (glass) components and filters assures that substantially unreacted linear aliquots of intermixed sample and carrier gas will pass to the capillary chromatograph column. The rate of flow of the carrier gas (at least 6 to 100 ml. per min.) is sufficient to insure that the apparatus is swept clean by carrier gas so that "band broadening" within the chromatograph column is avoided. Demountability of the apparatus permits removal and cleaning of the injector, liner, baffle and filter components to avoid chemical build-up and progressive sample degradation. Repetitive accuracy in capillary chromatographic analysis of very small substantially unreacted samples (e.g., 0.01 microliters) is thus assured.
In an inlet splitter for a gas chromatograph, a body having aligned injector and mixing chambers, means to heat said body and said chambers, elongate means forming an inert pathway between said injector and mixing chambers, said elongate means having an inlet in said injector chamber, and a baffled outlet opening to an expansion zone in said mixing chamber, means injecting an analysis sample into the inert pathway of said elongate means, means introducing a continuous flow of carrier gas to said inert pathway of said elongate means, said carrier gas serving to pick up, vaporize and convey injected sample through said electronic means and baffled outlet to said expansion zone, means forming a part of a gas chromatograph to withdraw a linear aliquot of intermixed sample and carrier gas from said expansion zone, and discharge means to effect removal of excess quantities of intermixed sample and carrier gas from said expansion zone and mixing chamber.
In an inlet splitter for a gas chromatograph, a body having aligned injector and mixing chambers, means to heat said body and said chambers, elongate means forming an inert pathway between said injector and mixing chambers, said elongate means having an inlet end in said injector chamber and a baffled outlet end forming an expansion zone in said mixing chamber, means lining said injector chamber and forming an inert annular pathway surrounding said elongate means, means injecting an analysis sample into one of said inert pathways of said injector chamber, means introducing a continuous flow of carrier gas to said pathways to flow through said inert annular pathway and into said inert elongate pathway, said carrier gas serving to pick up, vaporize and convey injected sample through said elongate means and baffled outlet to said expansion zone, means forming a part of a gas chromatograph to withdraw a linear aliquot of intermixed sample and carrier gas from said expansion zone, and discharge means to effect removal of excess quantities of intermixed sample and carrier gas from said expansion zone and mixing chamber.
A substantially nonreactive linear inlet splitter for a gas chromatograph, comprising an elongate body, said body being provided with first and second substantially cylindrical interior passages, each having inlet and outlet ends, the outlet end of said first interior passage coinciding with the inlet end of said second interior passage, said second interior passage being of sufficient diameter to axially receive the inlet end of a chromatograph column, said body having a relatively small instrument opening adjacent the inlet end of said first interior passage, a self-sealing septum adjacent said instrument opening, removable closure means for the end of said interior passage, said closure means having a needle aperture therein in alignment with the instrument opening in said body to thereby facilitate introduction of an analysis sample, substantially inert tubular liner means extending from a position closely adjacent said instrument opening to a position within said second interior passage means, said inert tubular lining means being removably supported in axially aligned relation within said first and second interior passages by demountable sealing means associated with said body, said tubular lining means providing a substantially inert pathway within said tubular liner means, means for introducing carrier gas to said inert pathway within said tubular liner so that the same passes through and along the length of said pathway within said tubular liner means, the portion of the tubular liner means within said second interior passage of the body being provided with baffle means to effect simultaneous reversal of direction and mixing of carrier and analysis sample gases passing therethrough, removable closure means for the outlet end of second interior passage of the body, said last named means including means to axially receive and support the inlet end of said chromatograph column so that the latter extends into the interior of said interior passage of the body, and means for controllably withdrawing excess amounts of intermixed carrier and analysis sample gases from said second interior passage of the body, whereby a sample introduced through said needle aperture is introduced within said inert pathway within said tubular liner where it is immediately picked up by carrier gas, intermixed with the same and introduced directly as a linear aliquot to the inlet end of said chromatograph column with contact being had only with the inert surfaces of said tubular liner.
A substantially nonreactive linear inlet splitter for a gas chromatograph, comprising an elongate body, said body being provided with first and second substantially cylindrical interior passage, each having inlet and outlet ends, the outlet end of said first interior passage coinciding with the inlet end of said second interior passage, said second interior passage being of sufficient diameter to axially receive the inlet end of a chromatograph column, a substantially inert injector cap lining said first interior passage, said injector cap having an end wall with a relatively small instrument opening adjacent the inlet end of said first interior passage, a self-sealing septum adjacent the end wall of said inert injector cap, removable closure means for the end of said interior passage, said closure means having a needle aperture therein in alignment with the instrument opening in said inert injector cap to thereby facilitate introduction of an analysis sample within said injector cap, substantially inert tubular liner means extending from a position closely adjacent said instrument opening within said injector cap to a position within said second interior passage means, said inert tubular lining means being removably supported in axially aligned relation within said first and second interior passages, said injector cap and tubular lining means cooperating within said first interior passage means to provide a substantially inert annular pathway surrounding said tubular lining means and communicating with a substantially inert pathway within said tubular liner means, means for introducing carrier gas to said annular pathway between the injector cap and tubular liner so that the same passes through the pathway within said tubular liner means, the portion of the tubular liner means within said second interior passage of the body being provided with baffle means to effect simultaneous reversal of direction and mixing of carrier and analysis sample gases passing therethrough, removable closure means for the outlet end of second interior passage of the body, said last named means including means to axially receive and support the inlet end of said chromatograph column so that the latter extends into the interior of said interior passage of the body, and means for controllably withdrawing excess amounts of intermixed carrier and analysis sample gases from said second interior passage of the body, whereby a sample introduced through said needle aperture is immediately picked up by carrier gas, intermixed with the same and introduced directly as a linear aliquot to the inlet end of said chromatograph column with contact being had only with the inert surfaces of said injector cap and tubular liner.
A glass inlet splitter for providing substantially linear sample fractionation for a capillary gas chromatograph, comprising an elongate body having at least two axially aligned substantially cylindrical interior passages, the first one of said interior passages having a sample receiving inlet end and a gas delivery outlet end, the second one of said interior passages having an inlet end coinciding with the outlet end of said first interior passage and an outlet end in substantially axial alignment with the inlet end of said capillary gas chromatograph, means for delivering an analysis sample to said first interior passage, said last named means including an apertured sample port and a self-sealing septum, means for introducing the carrier gas to said first interior passage including conduit means in said elongate body adjacent the outlet end of said first interior passage, means for mixing a sample with the carrier gas for delivery to said second interior passage, said mixing and delivery means including an elongate glass tube extending between said first and second interior passages and a glass injector cap lining the interior surfaces of said first interior passage, said injector cap having an end wall with a relatively small instrument opening in axial alignment with the aperture in said sample port, mounting and sealing means positioned in the coinciding outlet and inlet end of said first and second interior passages, said mounting and sealing means supporting said elongate glass tube in axial aligned relation within said first and second interior passages, mounting and sealing means closing the outlet end of said second interior passage, said last named means supporting said capillary chromatograph column so that the inlet end thereof is positioned within said second interior passage, glass baffle means supported within said second interior passage adjacent an outlet end of said elongate glass tube, said glass baffle means including an outer forwardly directed substantially cylindrical cup means and an inner rearwardly directed cup means, said rearwardly directed cup means surrounding an outlet end of said glass tube so as to effect mixing and reversal of direction of gases discharged by said elongate glass tube, said outer forwardly directed cup means surrounding said inner cup means so as to effect a mixing and reversal of gases discharged from said inner cup means, said outer cup means including a substantially cylindrical portion concentrically surrounding the inlet end of said capillary chromatograph column, and means for controllably withdrawing excess amounts of intermixed carrier gas and sample from said second interior passage, whereby sample introduced through said sample port is picked up by carrier gas adjacent the small instrument opening of said glass injector cap, intermixed with the same within said elongate glass baffle means and introduced directly as a linear aliquot to the inlet end of said capillary chromatograph with contact being had only with the inner surfaces of the injector cap, elongate tube and baffle means.
In a linear fractionation method for providing substantially pure sample aliquots for capillary gas chromatography, the steps of preheating a stream of carrier gas, introducing said stream of carrier gas to an inner inert core passage, heating said inner inert core passage to maintain a desired elevated temperature of said carrier gas, introducing an analysis sample to said stream of carrier gas within said inner inert core passage to flow with said stream of carrier gas through said core passage, said carrier gas serving to vaporize said sample and thereby form a mixed gaseous stream containing vaporized sample and carrier gas, introducing said mixed gaseous stream to an inert tortuous pathway wherein the direction of flow of said mixed gaseous stream is reversed in such fashion as to obtain a substantially complete turbulent mixing of said vaporized sample and carrier gases, and directing a predetermined volume of hot intermixed sample and carrier gases to the inlet of a capillary gas chromatograph to thereby cause separation of a desired aliquot of the same for capillary chromatographic analysis, the vaporization and intermixing of said sample and the separation of said desired aliquot of intermixed sample and carrier gases taking place wholly within the inert nonreactive environment of said inner inert core passages and said inert tortuous pathway.
In a linear fractionation method for providing substantially pure sample aliquots for capillary gas chromatography, the steps of preheating a stream of carrier gas, introducing said stream of carrier gas to an outer inert annular passage, reversing the direction of said stream of carrier gas to pass inwardly of said outer passage through an inner inert core passage, heating said outer and inner passages to maintain a desired elevated temperature of said carrier gas, introducing an analysis sample to said stream of carrier gas at the point of reversal of direction of said stream so as to flow with said stream of carrier gas through said core passage, said carrier gas serving to vaporize said sample and thereby form a mixed gaseous stream containing vaporized sample and carrier gas, introducing said mixed gaseous stream to an inert tortuous pathway wherein the direction of flow of said mixed gaseous stream is reversed a sufficient number of times to obtain a substantially complete turbulent mixing of said vaporized sample and carrier gases, and directing a predetermined volume of hot intermixed sample and carrier gases to the inlet of a capillary gas chromatograph to thereby cause separation of a desired aliquot of the same for capillary chromatographic analysis, the vaporization and intermixing of said sample and the separation of said desired aliquot of intermixed sample and carrier gases taking place wholly within the inert nonreactive environment of said annular and core passages and said tortuous pathway.
Dependencies are inferred from the claim text.