Chromatographic analysis apparatus

Claim 1

Apparatus for chromatographically analyzing volatile components present in a nonvolatile matrix including, in combination: (a) An oven, (b) A sample cylinder positioned in said oven and including; (i) a sealable entry port external of said oven for admitting and withdrawing a sample boat from said cylinder, (ii) a gas inlet, and (iii) a gas outlet, (c) A packed chromatographic analysis column positioned in said oven and including; (i) a gas inlet, and (ii) a gas outlet, (d) A detector downstream of said analysis column, (e) A carrier gas line running through said oven, (f) First and second packed chromatographic trap columns external of said oven, (g) A valve assembly external of said oven; (h) Said valve assembly having inlet/outlet connections to; (i) the inlet and the outlet of the first trap column, (ii) the inlet and the outlet of the second trap column, (iii) the carrier gas line, (iv) a line connecting to the outlet of the sample cylinder, (v) a line connecting to the inlet of the analysis column, and (vi) a vent, (j) Said valve assembly having two operating positions such that; (i) when the valve assembly is in its first operating position, gas introduced into the sample cylinder flows through the first trap column and is vented to the atmosphere, while gas introduced into the gas carrier line flows through the second trap column, the analysis column, and the detector, (ii) when the valve assembly is in its second operating position, gas introduced into the sample cylinder flows through the second trap column and is vented to the atmosphere, while gas introduced into the gas carrier line flows through the first trap column, the analysis column, and the detector, and (iii) the direction of gas flow through each of the trap columns is reversed when the valve assembly is rotated from one of its operating positions to its other operating position; (k) First heating means associated with said oven and including a controller capable of selectively maintaining said oven at a preselected lower temperature and a preselected higher temperature, (l) Second heating means which maintain the detector at an elevated temperature at least as high as the higher preselected temperature of said oven, (m) Third heating means which maintain the valve assembly and the lines running therefrom to the oven at a temperature at least as high as the higher preselected temperature of said oven, (n) Fourth heating means associated with the first trap column and capable of rapidly heating said column to a selected temperature well above the higher preselected temperature of said oven, (o) Fifth heating means associated with the second trap column and capable of rapidly heating said column to a selected temperature well above the higher preselected temperature of said oven, (p) Means associated with each of the fourth and fifth heating means for deactivating said heating means when the column reaches its selected temperature, (q) Switch means which permit only alternate activation of the fourth and fifth heating means, (r) First control means which activate the first, second, and third heating means, and (s) Second timed control means which: (i) at the beginning of its cycle activates the controller of the first heating means so that the oven temperature is heated to and then maintained at its preselected higher temperature, (ii) at the beginning of its cycle activates the fourth or fifth heating means, and (iii) at the end of its cycle activates the controller of the first heating means so that the oven temperature is cooled to and then maintained at its preselected lower temperature.

Claim 6

A method for chromatographically analyzing a plurality of samples having volatile components present in a non-volatile matrix by a process carried out in two repetitive, alternating operating cycles, said process consisting essentially of; in the first cycle; (a) Introducing a weighed sample into a heating cylinder positioned in an oven heated to a preselected lower temperature, (b) Increasing the oven temperature to a preselected higher temperature and then maintaining its temperature at said preselected higher temperature for the duration of said cycle. (c) Introducing a first inert carrier gas into said cylinder at a preselected flow rate; (d) Feeding said first carrier gas from said cylinder to a first packed chromatographic absorption trap column while maintaining its temperature at least as high as its temperature upon leaving said cylinder, (e) Passing said carrier gas into and through said first trap column and to the atmosphere while maintaining said trap column at ambient temperature; the direction of gas flow through said trap column being reversed from the direction of flow in the immediately preceding operating cycle, (f) Rapidly heating a second packed chromatographic absorption trap column to a temperature at least as high as the higher preselected temperature of the oven and then terminating said heating, (g) Feeding a second heated carrier gas at a preselected rate into and through said second trap column and to the inlet of a chromatographic analysis column positioned in said oven, the direction of gas flow through said trap column being reversed from the direction of flow in the immediately preceding operating cycle, (h) Feeding the outlet gas of the analysis column to a detector which analyzes said output gas and generates signals indicative of its chemical composition, and (j) Cooling said oven to its lower preselected temperature at the end of the cycle and removing the sample from the sample cylinder, in the second cycle; (k) Repeating each of steps (a) to (j) with the following modifications: (i) heating the first trap column in lieu of the second trap column, (ii) maintaining the second trap column at ambient temperature, (iii) passing the first carrier gas through the second trap column, (iv) passing the second carrier gas through the first trap column.

Claim 7

A method for chromatographically analyzing a plurality of samples having volatile components present in a non-volatile matrix by a process carried out in two repetitive, alternating operating cycles, said process consisting essentially of; in the first cycle; (a) Introducing a weighed sample into a heating cylinder positioned in an oven heated to a preselected lower temperature, (b) Increasing the oven temperature to a preselected higher temperature and then maintaining its temperature at said preselected higher temperature for the duration of said cycle. (c) Introducing a first inert carrier gas into said cylinder at a preselected flow rate; (d) Feeding said first carrier gas from said cylinder to a first packed chromatographic absorption trap column while maintaining its temperature at least as high as its temperature upon leaving said cylinder, (e) Passing said carrier gas into and through said first trap column and to the atmosphere while maintaining said trap column at ambient temperature; the direction of gas flow through said trap column being reversed from the direction of flow in the immediately preceding operating cycle, (f) Rapidly heating a second packed chromatographic absorption trap column to a temperature at least as high as the higher preselected temperature of the oven and then terminating said heating, (g) Feeding a second heated carrier gas at a preselected rate into and through said second trap column and to the inlet of a chromatographic analysis column positioned in said oven, the direction of gas flow through said trap column being reversed from the direction of flow in the immediately preceding operating cycle, (h) Feeding the outlet gas of the analysis column to a detector which analyzes said output gas and generates signals indicative of its chemical composition, and (j) Cooling said oven to its lower preselected temperature at the end of the cycle and removing the sample from the sample cylinder, in the second cycle; (k) Repeating each of steps (a) to (j) with the following modifications: (i) heating the first trap column in lieu of the second trap column, (ii) maintaining the second trap column at ambient temperature, (iii) passing the first carrier gas through the second trap column, (iv) passing the second carrier gas through the first trap column.