Gas chromatographic analysis method and apparatus

A gas chromatographic apparatus for determining at least the elemental carbon, hydrogen and nitrogen of a sample, which comprises:

• a closed, heated combustion chamber,
• means for introducing oxygen into said chamber,
• means for introducing a sample into said chamber,
• a first source of carrier gas,
• means for introducing said first carrier gas into said chamber,
• a first chromatographic column in communication with said chamber,
• a first detector means in communication with said first column,
• a second chromatographic column,
• a second source of carrier gas,
• a second detector means in communication with said second column,
• a third chromatographic column,
• a third source of carrier gas,
• a third detector means in communication with said third column,
• a first valve means, including first actuation means and first delay conduit means, in communication with said first detector means and connected to said second carrier gas source, for flowing the effluent from said first detector means through said first delay conduit means to a first conduit means and for flowing said second carrier gas through a second conduit means to said second column when said first valve means is in the first position, and upon actuation of said first valve means wherein said first valve means is changed from the first position to the second position, for flowing said second carrier gas through said first delay conduit means and into said second conduit means thereby carrying at least a portion of the contents of said first delay conduit means into said second column, and for directing the effluent from said first detector means through said first conduit means;
• a second valve means, including second actuator means and second delay conduit means, in communication with said first valve means through said first conduit and connected to said third carrier gas source, for flowing the effluent from said first conduit means through said second delay conduit means and for flowing said third carrier gas through a third conduit means to said third column when said second valve means is in the first position, and upon actuation of said second valve means wherein said second valve means is changed from the first position to the second position, for flowing said third carrier gas through said second delay conduit means and into said third conduit means thereby carrying at least a portion of the contents of said second delay conduit means into said third column.

A gas chromatographic apparatus for determining at least the elemental sulfur and oxygen of a sample, which comprises:

• a closed, heated pyrolysis chamber,
• means for introducing a sample into said pyrolysis chamber,
• a source of hydrogen gas,
• means for introducing hydrogen gas in to said pyrolysis chamber,
• a first source of carrier gas,
• means for introducing said first carrier gas into said pyrolysis chamber,
• a first chromatographic column in communication with said pyrolysis chamber,
• a first detector means in communication with said first column,
• a second chromatographic column,
• a second source of carrier gas,
• first valve means, including first actuator means and first delay conduit means, in communication with said first detector means and connected to said second carrier gas source, for flowing the effluent from said first detector means through said first delay conduit means and for flowing said second carrier gas through a first conduit means to said second column when said first valve means is in the first position, and upon actuation of said first valve means wherein said first valve means is changed from the first position to the second position, for flowing said second carrier gas through said first delay conduit means and into said first conduit means thereby carrying at least a portion of the contents of said first delay conduit means into said second column, and
• a second detector means in communication with said second column.

A gas chromatographic apparatus for determining at least the elemental sulfur and oxygen of a sample, which comprises:

• a close, heated pyrolysis chamber,
• means for introducing a sample into said pyrolysis chamber,
• a source of hydrogen gas,
• a first source of carrier gas,
• means for introducing hydrogen gas into said pyrolysis chamber,
• means for introducing said first carrier gas into said pyrolysis chamber,
• a first chromatographic column in communication with said pyrolysis chamber,
• a first detector means in communication with said first column,
• a second chromatographic column,
• a second source of carrier gas,
• a second detector means in communication with said second column,
• a third chromatographic column,
• a third source of carrier gas,
• a third detector means in communication with said third column,
• a first valve means, including first actuation means and first delay conduit means, in communication with said first detector means and connected to said second carrier gas source, for flowing the effluent from said first detector means through said first delay conduit means to a first conduit means and for flowing said second carrier gas through a second conduit means to said second column when said first valve means is in the first position, and upon actuation of said first valve means wherein said first valve means is changed from the first position to the second position, for flowing said second carrier gas through said first delay conduit means and into said second conduit means thereby carrying at least a portion of the contents of said first delay conduit means into said second column, and for directing the effluent from said first detector means through said first conduit means;
• a second valve means, including second actuator means and second delay conduit means, in communication with said first valve means through said first conduit and connected to said third carrier gas source, for flowing the effluent from said first conduit means through said second delay conduit means and for flowing said third carrier gas through a third conduit means to said third column when said second valve means is in the first position, and upon actuation of said second valve means wherein said second valve means is changed from the first position to the second position, for flowing said third carrier gas through said second delay conduit means and into said third conduit means thereby carrying at least a portion of the contents of said second delay conduit means into said third column.

An apparatus comprising:

• an elongated conduit suitable for passing a substance therethrough, said conduit having an elongated inlet means, a first chamber, a second chamber and an outlet means in that order,
• wherein said elongated inlet means is of sufficient length to preclude the condensation of a combustion gas on the walls thereof when the apparatus is used for oxidatively decomposing a sample in a chromatographic analyzer,
• wherein said first chamber and said second chamber are partially formed by quartz wool packing having a melting point of at least 1200.degree. C.,
• wherein said inlet chamber has a volume within a range of about 20 to about 50 cubic centimeters and said second chamber has a volume within a range of about 5 to about 10 cubic centimeters,
• wherein said quartz wool packing supports at least one quartz chip having a 1/8 inch diameter and a melting point of at least 1200.degree. C.,
• wherein a dampening chamber is positioned between and in communication with said second chamber and said outlet means,
• wherein said dampening chamber is substantially filled with quartz wool packing having a melting point of at least 1200.degree. C., and
• wherein said elongated conduit is constructed of quartz glass.

A method for determining at least the elemental carbon, hydrogen and nitrogen content of a sample which comprises in combination, the steps of:

• a. introducing an oxygen source into a closed, heated combustion chamber,
• b. introducing a measured sample into said chamber,
• c. oxidatively decomposing said sample whereby the resulting reaction product mixture contains as its principal components a carbon dioxide group, a water group and a nitrogen group,
• d. retaining said reaction product mixture in said chamber until combustion of the sample is substantially complete,
• e. sweeping substantially all of the reaction product mixture from said chamber with a first inert carrier gas at a predetermined flow rate,
• f. passing said reaction product mixture and said inert gas through a first gas chromatographic column whereby said mixture is separated into said carbon dioxide group, said nitrogen group and said water group, said carbon dioxide group and said nitrogen group being eluted substantially simultaneously and prior to said water group,
• g. passing the water group effluent eluting from said first column through a first detecting means to detect the quantity of water in said water group,
• h. passing the carbon dioxide group and the nitrogen group effluent eluting from said first detecting means to a second gas chromatographic column,
• i. introducing a second carrier gas at a predetermined flow rate to the inlet of said second column thereby passing said carbon dioxide group and said nitrogen group through said second column whereby said nitrogen group and said carbon dioxide group are further separated,
• j. venting said water group eluting from said first detecting means,
• k. passing the effluent from said second chromatographic column through a second detecting means to detect the quantities of carbon dioxide in said carbon dioxide group and nitrogen in said nitrogen group, and
• l. separately determining from the quantity of said water, said carbon dioxide and said nitrogen the quantities of elemental hydrogen, carbon and nitrogen of said sample.

A method for determining at least the elemental carbon, hydrogen and nitrogen content of a sample which comprises in combination, the steps of:

• a. introducing an oxygen source into a closed, heated combustion chamber,
• b. introducing a measured sample into said chamber,
• c. oxidatively decomposing said sample whereby the resulting reaction product mixture contains as its principal components a water group, carbon dioxide group and nitrogen group,
• d. retaining said reaction product mixture in said chamber until combustion of said sample is substantially complete,
• e. sweeping substantially all of the reaction product mixture from said chamber with a first carrier gas at a predetermined flow rate,
• f. passing said reaction product mixture and said carrier gas through a first gas chromatographic column whereby said mixture is separated into said carbon dioxide group, said nitrogen group and said water group, said carbon dioxide group and said nitrogen group being eluted prior to said water group,
• g. passing the water group effluent from said first column through a first detecting means to detect the quantity of water in said water group,
• h. passing said nitrogen group effluent eluting from said first detecting means to a second gas chromatographic column,
• i. introducing a second carrier gas at a predetermined flow rate to the inlet of said second column thereby sweeping said nitrogen group through said column,
• j. passing said carbon dioxide group effluent eluting from said first chromatographic column to a third chromatographic column,
• k. introducing a third carrier gas at a predetermined flow rate to the inlet of said third column thereby sweeping said carbon dioxide group through said column,
• l. venting said water group eluting from said first detecting means,
• m. passing the effluent from said second column through a second detecting means to detect the quantity of nitrogen in said nitrogen group,
• n. passing the effluent from said third column through a third detecting means to detect the quantity of carbon dioxide in said carbon dioxide group, and
• o. separately determining from the quantity of said water, said carbon dioxide and said nitrogen the quantities of elemental hydrogen, carbon and nitrogen of said sample.

A method for determining at least the elemental oxygen content of a sample which comprises, in combination, the steps of:

• a. introducing a measured sample into a closed, heated pyrolysis chamber,
• b. pyrolytically decomposing said sample whereby the resulting reaction product mixture comprises water, carbon dioxide and carbon monoxide,
• c. retaining said reaction product mixture in said chamber until pyrolysis of said sample is substantially complete,
• d. sweeping substantially all of the reaction product mixture with a first carrier gas at a predetermined rate through a bed of carbon thereby converting at least a portion of said carbon dioxide to carbon monoxide and at least a portion of said water to carbon monoxide and hydrogen and thereafter passing the resulting product mixture and said carrier gas through a first gas chromatographic column whereby said mixture is separated into said carbon monoxide, said carbon dioxide, and said water, said carbon monoxide and said carbon dioxide being eluted prior to said water,
• e. passing the effluent from said first column through a first detecting means to detect the quantity of said water,
• f. passing said carbon monoxide and said carbon dioxide eluting from said first detecting means to a second gas chromatographic column,
• g. introducing a second carrier gas at a predetermined flow rate to the inlet of said second column thereby passing said carbon monoxide and said carbon dioxide through said second column whereby said carbon monoxide and said carbon dioxide are further separated,
• h. venting said water eluting from said first detecting means,
• i. passing the effluent from said second chromatographic column through a second detecting means to detect the quantities of said carbon dioxide and said carbon monoxide, and
• j. determining from the quantity of water, carbon dioxide and carbon monoxide the quantity of elemental oxygen of said sample.

A method for determining at least the elemental sulfur and oxygen content of a sample which comprises, in combination, the steps of:

• a. introducing a measured sample into a closed, heated pyrolysis chamber,
• b. pyrolytically decomposing said sample whereby the reaction product mixture comprises carbon monoxide, carbon dioxide, water and sulfur oxides,
• c. retaining said reaction product mixture in said chamber until pyrolysis of said sample is substantially complete,
• d. sweeping substantially all of the reaction product mixture with a first inert carrier gas at a predetermined rate through a bed of carbon, thereby converting at least a portion of said carbon dioxide to carbon monoxide, at least a portion of said water to carbon monoxide and hydrogen, and at least a portion of said sulfur oxides together with hydrogen to carbon monoxide and hydrogen sulfide, and thereafter passing the resulting product mixture and said first carrier gas through a first gas chromatographic column whereby said mixture is separated into said carbon monoxide, said hydrogen sulfide and said water, said carbon monoxide being eluted prior to said hydrogen sulfide which is prior to said water,
• e. passing the effluent from said first column through a first detecting means to detect the quantity of said water and said hydrogen sulfide,
• f. passing said carbon monoxide eluting from said first detecting means to a second gas chromatographic column,
• g. introducing a second carrier gas at a predetermined flow rate to the inlet of said second column thereby passing said carbon monoxide through said second column,
• h. venting said water and said hydrogen sulfide eluting from said first detecting means,
• i. passing the effluent from said second column through a second detecting means to detect the quantity of said carbon monoxide, and
• j. determining from the quantity of water, carbon monoxide and hydrogen sulfide the quantity of elemental oxygen and elemental sulfur of said sample.

A method for oxidatively decomposing a sample which comprises, in combination, the steps of:

• a. passing oxygen into a first heated combustion zone and a second heated combustion zone to substantially fill each zone with oxygen,
• b. passing a sample into said first heated combustion zone wherein said sample is converted to gases which are at least partially oxidatively decomposed in the first heated combustion zone,
• c. passing an inert carrier gas into said first heated combustion zone to sweep the gases therein into said second heated combustion zone to ensure essentially complete oxidative decomposition of said sample gases, and
• d. passing said oxidatively decomposed sample gases through an outlet zone.