US3714812A - Electron capture identification apparatus - Google Patents

Electron capture identification apparatus Download PDF

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Publication number
US3714812A
US3714812A US00039602A US3714812DA US3714812A US 3714812 A US3714812 A US 3714812A US 00039602 A US00039602 A US 00039602A US 3714812D A US3714812D A US 3714812DA US 3714812 A US3714812 A US 3714812A
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United States
Prior art keywords
chromatographic
fluid communication
columns
sampling valve
grooves
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00039602A
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English (en)
Inventor
J Drinkwater
A Evans
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Shell USA Inc
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Shell Oil Co
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Publication date
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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
    • G01N30/468—Flow patterns using more than one column involving switching between different column configurations
    • 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
    • G01N30/70—Electron capture detectors
    • 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
    • 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
    • G01N30/466—Flow patterns using more than one column with separation columns in parallel
    • G01N30/467—Flow patterns using more than one column with separation columns in parallel all columns being identical
    • 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
    • G01N30/60—Construction of the column
    • G01N30/6047—Construction of the column with supporting means; Holders

Definitions

  • FIG 4 IN JOHN W. D
  • This invention relates to analytical apparatus.
  • Gas chromatographic separation is conventionally carried out in columns or tubes which are packed with a solid adsorbent material (in gas-solid chromatography) or with a solid supporting material impregnated with liquid (in gas-liquid chromatography).
  • the present invention provides apparatus which is particularly applicable to the detection of one component of a mixture of substances, and more particularly applicable to the analysis of sequential samples of a mixture of substances.
  • FIG. 1 is a schematic view of the gas chromatographic device of this invention in its most general form
  • FIG. 2 is a flow diagram illustrating the operation of the invention
  • FIG. 3 is a vertical section of the gas chromatographic device and of the after-column
  • FIG. 4 is a horizontal section along line 4-4 of FIG. 3.
  • FIG. 5 is a plan view of the top plate of the device of FIG. 3 along line 5-5 of FIG. 3;
  • FIG. 6 is a plan view of the bottom plate of the device of FIG. 3 along line 66 of FIG. 3.
  • FIG. 1 of the accompanying drawings shows diagrammatically, in vertical section, one embodiment of the apparatus, which comprises a sampling valve 1, a series of six chromatographic columns 2, and a detection device 3. Provision is also made (4) for back flushing of the chromatographic columns with the carrier gas.
  • the means for transferring a sample of material to be analyzed to the chromatographic unit may be any suitable sampling device, such as a sampling valve, and we 1 have used with particular success sampling valves of the kind described in our copending British application Ser. No. 4476/69 filed Jan. 27, 1969 Such valves can be particularly useful when samples have to be taken from materials which are under high pressure.
  • the chromatographic unit conveniently consists of a plurality of chromatographic columns arranged with their long axes parallel to and equidistant from a common axis around which the columns rotate, suitably driven, so that they may be brought in succession to a sample injection station.
  • the series of chromatographic columns consist essentially of tubes in a cylindrical piece of metal or other suitable material which is rotatable on its axis.
  • conventional columns of glass, metal or other suitable material could be supported in a suitable fashion so that they could be moved to the various stations as necessary.
  • the actual dimensions of the chromatographic columns will, of course, be chosen with regard to their particular purpose and in accordance with known chromatographic principles.
  • the apparatus illustrated is provided with means for back-flushing the columns, which allows for speedier analysis.
  • the detection device may be any convenient device capable of detecting, with appropriate accuracy and speed, the required substance.
  • a detector may be capable, for example, of detecting electron absorbing materials.
  • the apparatus of the invention has been employed in the direction of the interface between two different liquid hydrocarbons travelling in succession in a pipeline, by the incorporation into one of the liquids, at the interface, of an appropriate quantity of a suitable tracer substance.
  • the electron capture detection device responds unselectively, that is to say, it detects not only the particular tracer substances employed but also the presence of other electron absorbing materials which may be present in the eluate from the columns; this continues, of course, even when no tracer substance is present.
  • the electron capture detector responds to the presence of, say, oxygen, so that even when the tracer substance is not present in the material being sampled the detector indicates the presence of a material having electron affinity.
  • a continuous record of electron absorbing material passing through the detector representing an electron absorbing background material, to which is added occasional peaks indicating the detection of an amount of a tracer substance.
  • This constant recording of a background material is useful in that it is an indication that the detection device is operating satisfactorily.
  • the baseline which represents the background electron absorbing material is uneven, due apparently to variation in the retention of detectable materials on the different columns of the multi-column chromatography unit.
  • a substantially even baseline has been obtained by passing the eluate from all the columns of the chromatographic unit through a further, common, column which retains the various detectable materials contributing to the baseline reading and releases them at a substantially constant rate, in effect smoothing out the variations in individual column characteristics and producing a much more even baseline against which the detection of tracer substances can be observed.
  • a common after-column into which eluate from the different chromatography columns passes before it enters the detector.
  • the after-column may be packed with any suitable material to constitute the stationary phase. Generally the packing material will be similar to that in the main columns. No repeated backflushing of this common column occurs, except on occasion when it may be desirable for periodic cleaning, since it operates continuously while-chromatography through any of the columns is going on.
  • FIG. 2 is a diagram showing the flow of a tracer substance after its transfer to an analysis apparatus comprising the after-column.
  • 11 is a nitrogen supply, the nitrogen serving as the carrier and flushing gas
  • 12 is a molecular sieve purifier to remove electron absorbing materials from the nitrogen
  • 1 is the sampling valve
  • 2 is the chromatographic unit
  • 13 is the aftercolumn
  • 3 is the detector
  • 14 and 15 are the nitrogen lines for chromatography and backflush respectively.
  • FIG. 3 is a vertical section through an embodiment of a valve/chromatographic unit comprising an aftercolumn and FIG. 4 is a section along the line 4-4 in FIG. 3.
  • the sampling valve 1 is a valve as described in our copending British application Ser. No. 4476/69 filed Jan. 27, 1969.
  • the chromatographic device consists of a cylindrical block of Duralumin rotatable about its axis, in which are drilled six columns, each 10 cm. long and 5 mm. in diameter. These are packed with a' suitable adsorbent material 21; the choice of material will present no difficulty to the skilled man. As an example, we have satisfactorily employed 25 percent squalene on Celite 545 for the separation of volatiles from hydrocarbons. In each column the packing is retained by a 3 mm. thick press-fit disc, 22, of sintered stainless steel (40 microns porosity).
  • Grooves 27, 28, 29, 30 in the stationary end plates 23, 26 of the cylinder direct the gas flow as required, allowing a 10 second analysis of the vapor fraction from the sampling valve 1 (grooves 27, 29) and 20 seconds back flushing time (grooves 28, 30).
  • the column is heated by an 85 watt cartridge element 24, in the bottom center of the unit.
  • the cylinder rotates on its spindle 25, driven by an electric motor (not shown) synchronously with the sampling valve.
  • the sampling valve 1 delivers, at 10 second intervals, 2 microlitres of the oil sample, and the volatiles including the SP are carried with the nitrogen, which is delivered at 25 ml/min, into the chromatography column 2 which at that time is in the sample inlet position.
  • the column is packed with 25 percent squalene on Celite 545 carrier. Chromatographic separation occurs in the column as it rotates, and after 10 seconds, during which time the SP will have passed through the column and into the after-column 13, the column reaches the backflushing position where the nitrogen stream is reversed so that materials retained in the columns are swept out.
  • the column temperature is maintained at 50C.
  • the eluate from the column 2 enters the aftercolumn 13 which is packed with the same material as the main columns.
  • the after-column 13 is a stainless steel tube 5 cm. long and 4 mm. in diameter. Variations in composition of the eluate, due for example to the differences in packing, etc. of the different columns, are smoothed out so that the eluate from the after-column 13 is substantially constant in its background component.
  • This eluate then passes to the electron capture detector where the presence of electron absorbing material is detected and registered electronically.
  • the detection of a tracer substance can be used in conventional apparatus (not shown) to control automatic switching of hydrocarbon or liquids when the tracer has been used as an interface indicator. In such applications the importance of an even baseline against which the tracer peak can be detected with certainty will be apparent.
  • rotation of I the cylinder is continuous, direction and duration of gas flow through the columns being controlled by the grooves 27, 28, 29, 30 shown in FIGS. 5 and 6 which represent, respectively, the fixed end plates 23 and 26 located at the sample inlet and outlet ends of the cylinder.
  • the cylinder could be made to rotate intermittently, so that the cylinder is stationary during the injection of the sample, although this arrangement is not preferred.
  • Apparatus as described above was used for the determination of the position of an interface between two different hydrocarbon oils travelling in contact in succession through a 50 cm. diameter pipeline.
  • the tracer substance was 25 ml of trichlorofluoromethane and the distance travelled before analysis was 190 Km.
  • Samples means for continuously revolving said chromatographic device at a substantially constant speed in timed sequence with the withdrawal of said sample by said sampling valve;
  • a source of carrier gas said source being in fluid communication with said sampling valve, said source also being in fluid communication with said chromatographic device;
  • a detector device for detecting the presence of said tracer material in the eluent from said chromatographic device, said detector device being in fluid communication with said chromatographic device;
  • said chromatographic device including a stationary lower plate provided with first and second grooves, said first groove being in fluid communication with said sampling valve for introduction of said sample into said chromatographic columns;
  • a stationary upper plate having first and second grooves similar to said first and second grooves in said lower plate, said second groove being in fluid communication with said carrier gas source for backflushing said chromatographic columns;
  • said member being positioned between said upper and lower stationary plates, said member having a plurality of chromatographic columns spaced equal distance from the longitudinal axis of said cylindrical member, said first and second grooves in said upper and lower stationary plates being arranged such that any one of said chromatography columns is in fluid communication with said second groove for substantially twice as long as any of said chromatographic columns is in fluid communication with said first groove.
  • the apparatus of claim 1 further including an after-column between said chromatographic device and said detector device.

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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)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Sampling And Sample Adjustment (AREA)
US00039602A 1969-05-22 1970-05-22 Electron capture identification apparatus Expired - Lifetime US3714812A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB26209/69A GB1272638A (en) 1969-05-22 1969-05-22 Chromatographic apparatus

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US3714812A true US3714812A (en) 1973-02-06

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US00039602A Expired - Lifetime US3714812A (en) 1969-05-22 1970-05-22 Electron capture identification apparatus

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DE (1) DE2024569A1 (enExample)
FR (1) FR2048544A5 (enExample)
GB (1) GB1272638A (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535620A (en) * 1983-08-12 1985-08-20 Internorth, Inc. Method for automatically measuring the amount of water in a natural gas pipeline with the aid of a computer controlled gas chromatograph
EP0512404A1 (en) * 1991-05-03 1992-11-11 Nalco Chemical Company Identification of liquid hydrocarbons using chemical markers
US20210033503A1 (en) * 2011-08-08 2021-02-04 Thermo Fisher Scientific Oy Apparatus for automated analysis

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2276589A1 (fr) * 1974-06-26 1976-01-23 Commissariat Energie Atomique Procede continu et dispositif d'analyse de gaz en temps reel
US5047073A (en) * 1990-02-27 1991-09-10 Transducer Research, Inc. Sorption separation apparatus and methods

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234499A (en) * 1937-04-27 1941-03-11 Mine Safety Appliances Co Air testing device
US3199274A (en) * 1961-07-26 1965-08-10 Perkin Elmer Corp Chromatography apparatus
US3363447A (en) * 1966-02-14 1968-01-16 Universal Oil Prod Co Multiple chromatograph column heater unit
US3444722A (en) * 1966-09-09 1969-05-20 Phillips Petroleum Co Device for supplying carrier gas to transport eluted portion of sample and to backflush chromatographic column
US3550429A (en) * 1967-11-16 1970-12-29 Texaco Inc Chromatographic analysis

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234499A (en) * 1937-04-27 1941-03-11 Mine Safety Appliances Co Air testing device
US3199274A (en) * 1961-07-26 1965-08-10 Perkin Elmer Corp Chromatography apparatus
US3363447A (en) * 1966-02-14 1968-01-16 Universal Oil Prod Co Multiple chromatograph column heater unit
US3444722A (en) * 1966-09-09 1969-05-20 Phillips Petroleum Co Device for supplying carrier gas to transport eluted portion of sample and to backflush chromatographic column
US3550429A (en) * 1967-11-16 1970-12-29 Texaco Inc Chromatographic analysis

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535620A (en) * 1983-08-12 1985-08-20 Internorth, Inc. Method for automatically measuring the amount of water in a natural gas pipeline with the aid of a computer controlled gas chromatograph
EP0512404A1 (en) * 1991-05-03 1992-11-11 Nalco Chemical Company Identification of liquid hydrocarbons using chemical markers
US20210033503A1 (en) * 2011-08-08 2021-02-04 Thermo Fisher Scientific Oy Apparatus for automated analysis

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Publication number Publication date
DE2024569A1 (de) 1970-12-10
FR2048544A5 (enExample) 1971-03-19
GB1272638A (en) 1972-05-03

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