Gas chromatography methods and apparatus
First Claim
1. In a method of performing gas chromatographic analysis wherein a sample is admitted to a chromatographic column and caused to travel in a direction from upstream to downstream from an inlet port of said column to an elution port, the improvement comprising the steps of(a) providing temperature control means in thermal transfer relation with said column, said temperature control means being adapted to heat or cool selected locations of said column(b) providing a curvilinearly shaped negative temperature gradient along said column by said temperature control means, with the temperature at the elution port of said column being maintained lower than the temperature at the inlet port thereof at all times except for the end of said analysis so that the sample will continuously be subjected to a lower temperature as it travels in a downstream direction along said column, said column and said temperature control means being capable of transferring changes of at least about 0.5°
- C. per second from said temperature control means to said column and(c) raising the temperature of the column at said elution port at the end of said analysis so that said sample will elute from the column.
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Abstract
Gas chromatographic methods and apparatus are disclosed whereby improved separation times and efficiency are achieved by provision of a time-programmable curvilinearly-shaped negative temperature gradient along the length of the chromatographic column. The gas phase sample traveling through the column always passes to a column zone having a lower temperature than the previous column zone. Accordingly, upon elution, sample bandwidths are compressed. Separation times may be decreased when compared to conventional isothermal or temperature programmed gas chromatography.
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Citations
31 Claims
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1. In a method of performing gas chromatographic analysis wherein a sample is admitted to a chromatographic column and caused to travel in a direction from upstream to downstream from an inlet port of said column to an elution port, the improvement comprising the steps of
(a) providing temperature control means in thermal transfer relation with said column, said temperature control means being adapted to heat or cool selected locations of said column (b) providing a curvilinearly shaped negative temperature gradient along said column by said temperature control means, with the temperature at the elution port of said column being maintained lower than the temperature at the inlet port thereof at all times except for the end of said analysis so that the sample will continuously be subjected to a lower temperature as it travels in a downstream direction along said column, said column and said temperature control means being capable of transferring changes of at least about 0.5° - C. per second from said temperature control means to said column and
(c) raising the temperature of the column at said elution port at the end of said analysis so that said sample will elute from the column. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- C. per second from said temperature control means to said column and
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20. Gas chromatographic apparatus of the type adapted to perform sample separation analysis comprising
(a) an open tubular chromatographic column having a sample inlet port located at an upstream portion of said column and a sample elution port at a downstream portion of said column, (b) temperature control means in thermal transfer relation with said column for imparting a curvilinearly shaped negative temperature gradient along said column whereby the downstream end of said column is maintained at a lower temperature than said upstream portion during all but the endpoint of said analysis, said column (a), and temperature control means (b) being capable of transferring changes of at least about 0.5° - C. per second from said temperature control means to said column.
- View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. Gas chromatographic apparatus comprising an open tubular chromatographic column having an upstream sample inlet port and a downstream sample elution port, a heater in thermal transfer relation with respect to said column, fluid regulating means for passing a heat exchange fluid into heat exchange relation with said column, said heater being operatively connected to a time and temperature control programmer and said fluid regulating means being operatively connected to a time and flow rate regulator whereby said heater and fluid regulating means provide a curvilinearly shaped negative temperature gradient along said column with a lower temperature being provided at said elution port than at said inlet port.
Specification