US3104541A - Gas chromatograph with improved zero shift - Google Patents

Gas chromatograph with improved zero shift Download PDF

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Publication number
US3104541A
US3104541A US28610A US2861060A US3104541A US 3104541 A US3104541 A US 3104541A US 28610 A US28610 A US 28610A US 2861060 A US2861060 A US 2861060A US 3104541 A US3104541 A US 3104541A
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United States
Prior art keywords
column
gas
detector
carrier gas
partial pressure
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Expired - Lifetime
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US28610A
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English (en)
Inventor
Henry J Noebels
Stanford B Spracklen
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Beckman Coulter Inc
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Beckman Instruments Inc
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Publication date
Priority to NL264424D priority Critical patent/NL264424A/xx
Priority to NL122618D priority patent/NL122618C/xx
Application filed by Beckman Instruments Inc filed Critical Beckman Instruments Inc
Priority to US28610A priority patent/US3104541A/en
Priority to GB12757/61A priority patent/GB946328A/en
Application granted granted Critical
Publication of US3104541A publication Critical patent/US3104541A/en
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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
    • G01N30/26—Conditioning of the fluid carrier; Flow patterns
    • G01N30/38—Flow patterns
    • G01N30/46—Flow patterns using more than one column
    • G01N30/461—Flow patterns using more than one column with serial coupling of separation columns

Definitions

  • a dual column chromatograph may be used with a sample having constituents with widely difiering boiling points.
  • the tw columns of the instrument will have different characteristics, one being selected to provide resolution of the higher boiling point fractions and the other to provide resolution of the lower boiling point fractions of the sample.
  • the instrument will have two possible gas flow paths and will be switched from one to the other at a particular time during the sample analysis. For example, the instrument is initially set to direct the carrier gas stream through the first column, then through the second column and then to the detector. At a particular time following injection of the sample, the flow path is changed to direct the carrier gas stream through the first column and then to the detector, by passing the second column.
  • the low boiling point fractions of the sample will pass through the first column very rapidly with little resolution while the higher boiling point fractions will be adequately separated.
  • the low boiling point fractions will be adequately resolved in the second column but the higher boiling point fractions would take an exorbitantly long period of time to pass through the second column. Therefore, the instrument is operated with the two columns in series initially so that the low boiling point fractions. will pass through the first column into the second column and be resolved. After the desired resolution has been obtained, the instrument is switched to the second flow path so that the higher boiling point fractions will bypass the second column and go directly to the detector.
  • a iurther object is to provide such an instrument wherein the partitioning agent of the second column is picked up by the carrier gas passing therethrough and including a gas equilibrator unit inserted in the second flow path, with the unit containing a quantity of the partitioning agent of the second column for equilibratin-g the partial pressure of the partitioning agent in the carrier gas as it passes therethrough to the partial pressure of the partitioning agent in the eluent of the record column.
  • each of the columns contains material that will change the partial pressure of the carrier gas passing therethrough and including means inserted in the flow path downstream from the second column that will change the partial pressure in the same manner as the first column.
  • a further object is to provide such an instrument wherein the second column is of the type which will strip partitioning agent of the first column from the carrier gas as it passes through the second column, and including means inserted in the flow path downstream from the second column for introducing additional first column partitioning agent into the carrier gas stream.
  • a further object of the invention is to provide suchan instrument including a partitioning agent filter positioned upstream of the second column for locking transmission of first column partitioning agent into the second column.
  • the invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description.
  • the drawing merely shows and the description merely describes preferred embodiments of the present invention which are given by way of illustration or example.
  • FIG. 1 is a diagrammatic representation of a dual column :gas chromatograph incorporating the invention of the present application;
  • FIG. 2 is a view similar to FIG. 1 of an alternative form
  • FIG- 3. is a view similar to FIG. 1 of another alternative form.
  • the carrier gas flows from the gas source through a'sample injection valve 10, a first-chromatographic column 11, a valve 12, a second chromatographic column .13, another valve 14, and the column side of a detector '15.
  • the valves 12, 14 provide an alternate or second flow pat through an equilibrato-r, such as a saturator unit 16, and through a restrictor 17;
  • the carrier gas also flows directly from the source through the reference side of the detector 15.
  • the restrictor 17 is designed to have the same gas flow impedance as the second column 13 so that the pressures and rate of flow will be the same for both flow paths.
  • the first column will contain polyglycol as a partitioning agent for resolving Water, acetonitrile and hydrocarbons
  • the second column will contain bis (2(2-methoxyethoxy)ethyl) ether as a partitioning agent for resolving propane, propylene and butane.
  • the carrier gas will be directed through the first and second columns. After the sample is injeoted at the injection valve 10, the lower boiling point fractions will pass through the first column relative-1y rapidly and will be resolved in the second column, while the higher boiling point fractions will be resolved in the first column.
  • the valves 12, 14 are switched to direct the carrier gas stream from the first column through the restrictor '17 to the detector so that the higher boiling point fractions will bypass the second column.
  • the present invention provides an instrument which substantially eliminates the zero shift and, hence, no compensation is required.
  • the sat-orator unit 16 is placed in the second flow path for producing the same effect on the carrier gas as is produced by the second column 13.
  • the column 13 may be six feet in length while the saturator unit may be three inches in length.
  • this length of saturator will be adequate to produce the same change in partial pressure as is produced by the column 13.
  • the partial pressure in the gas and, there-fore, its thermal conductivity will be the same regardless of whether the carrier gas follows the first flow path or the second flow path. Under these circumstances, the detector does not undergo any change when the flow paths are changed and the zero-shift is eliminated.
  • the carrier gas picks up some partitioning agent but does not become saturated, e. g., where the column is relatively short. Then the unit 16 would be operated as :an equilibrator to add substantially the same quantity of partitioning agent to the carrier gas so as to have the desired equal charge in partial pressure in both paths.
  • the panticular location of the unit 16 in the second flow path is not critical.
  • the unit 16 is shown between the valve 12 and the restrictor 17, but could equally well be placed downstream of the restrictor 17, or between the first column and the valve 12.
  • FIG. 2 An alternative form of the invention is shown in FIG. 2, this form being particularly adapted for use in instru- .
  • the second column does not add any material to the carrier gas but does remove material from the carrier gas.
  • a first column 20 may use parailin oil as a partitioning agent for separating ethane, propane and butane.
  • a second column 21 may be in the form of a molecular sieve for separating oxygen, nitrogen and carbon monoxide.
  • the carrier gas passes through the first column, it will pick up partitioning agent producing a partial pressure in the carrier.
  • the second column will remove this partitioning agent from the carrier gas as it flows therethrough so that the eluent from the second column will have a different partial pressure than the eluent from the first column.
  • a gas sat-orator unit 22 is positioned in the first flow path between .the second column and the detector.
  • This saturator unit contains a quantity of the partitioning agent of the first column so that the eluent from the second column will have the partitioning agent replaced therein with the resultant increase in partial pressure to match that in the carrier gas following the second flow path.
  • the unit 22 functions as a partial pressure equalizer to restore the carrier gas to the condition it was in as it entered the second column (i.e., to the condition it was in as it left the first column).
  • FIG. 3 shows an alternative form of the apparatus of FIG. 2 including a filter unit 25 inserted in the flow path ahead of the second column 21.
  • the filter unit is selected to remove the partitioning agent of the first column .firorn the carrier gas as it passes therethrough before arriving at the second column.
  • the filter may be a short length of column filled with activated charcoal that will absorb the partitioning agent.
  • a source of carrier gas a source of carrier gas
  • a first chromatographic column a second chromatographic column containing a material that will change the partial pressure in a gas passing therethrough
  • a partial pressure sensitive detector a flow restrictor having a gas flow impedance substantially equal to the gas flow impedance of said second column
  • a source of carrier gas a source of carrier gas
  • a first chromatographic column a second chromatographic column containing a partitioning agent which is picked up by the carrier gas passing therethrough
  • a partial pressure sensitive detector a flow restrictor having a gas flow impedance substantially equal to the gas flow impedance of said second column
  • a source of carrier gas a first chromatographic column; a second chromatographic column containing a material that will change the partial pressure in a gas passing therethrough; a partial pressure sensitive detector; a fiow restrictor having a gas fiow impedance substantially equal to the gas fiow impedance of said second column; means for selectively coupling said source, said first column, said second column and said detector to form a first gas fiow path, or said source, said first column, said restrictor and said detector to form a second gas fiow path; and means inserted in said first flow path between said second column and said detector, said means containing a quantity of said material whereby the partial pressure in the carrier gas passing therethrough is changed in the opposite manner as the partial pressure is changed by said second column.
  • a source of carrier gas a first chromatographic column containing a partitioning agent which is picked up by the carrier gas passin therethrough; a second chromatographic column containing a material that will strip said partitioning agent from the carrier gas passing therethrough; a partial pressure sensitive detector; a flow restrictor having a gas flow impedance substantially equal to the gas fiow impedance of said second column; means for selectively coupling said source, said first column, said second column and said detector to form a first gas fiow path, or said source, said first column, said restrictor and said detector to form a second gas fiow path; and a gas equilibration unit inserted in said first flow path between said second column and said detector, said unit containing a quantity of the partitioning agent of said first column for equilibrating the partial pressure of partitioning agent in the carrier gas passing therethrough to that of the eluent of said first column.
  • a source of carrier gas a source of carrier gas
  • a first chromatographic column containing a partitioning agent which is picked up by the carrier gas passing therethrough
  • a second chromatographic column containing a material that will strip said partitioning agent from the carrier gas passing therethrough
  • a partial pressure sensitive detector a flow restrictor having a gas fiow impedance substantially equal to the gas fiow impedance of said second column
  • a partitioning agent filter for removing partitioning agent from gas passing therethrough
  • a gas equilibration unit inserted in said first flow path between said second column and said detector, said unit containing a quantity of the partitioning agent of said first column for equilibrating the partial pressure of partitioning agent in the carrier gas passing therethrough to that of the eluent

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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)
  • Immunology (AREA)
  • Pathology (AREA)
  • Treatment Of Liquids With Adsorbents In General (AREA)
US28610A 1960-05-12 1960-05-12 Gas chromatograph with improved zero shift Expired - Lifetime US3104541A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL264424D NL264424A (enrdf_load_stackoverflow) 1960-05-12
NL122618D NL122618C (enrdf_load_stackoverflow) 1960-05-12
US28610A US3104541A (en) 1960-05-12 1960-05-12 Gas chromatograph with improved zero shift
GB12757/61A GB946328A (en) 1960-05-12 1961-04-10 Gas chromatograph with improved shift

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Application Number Priority Date Filing Date Title
US28610A US3104541A (en) 1960-05-12 1960-05-12 Gas chromatograph with improved zero shift

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US3104541A true US3104541A (en) 1963-09-24

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GB (1) GB946328A (enrdf_load_stackoverflow)
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5476000A (en) * 1994-03-31 1995-12-19 Hewlett-Packard Company Retention time stability in a gas chromatographic apparatus

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE24876E (en) * 1955-12-16 1960-09-27 Multiple column chromatographic apparatus

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE24876E (en) * 1955-12-16 1960-09-27 Multiple column chromatographic apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5476000A (en) * 1994-03-31 1995-12-19 Hewlett-Packard Company Retention time stability in a gas chromatographic apparatus

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NL122618C (enrdf_load_stackoverflow)
GB946328A (en) 1964-01-08
NL264424A (enrdf_load_stackoverflow)

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