Gas chromatograph having integrated pressure programmer

A method for performing a chromatographic separation of a given compound wherein said compound is injected into a pressurized carrier gas and passed through a column and wherein a portion of said column is subjected to a temperature profile, comprising the steps of:

• determining the pressure of said carrier gas and generating a pressure information signal representative of said pressure;
• storing desired carrier gas mass flow information and temperature profile information;
• and
• controlling the pressure of said carrier gas in response to said flow information, said temperature profile information and said pressure information signal, so that as said temperature profile information changes with time, the desired mass flow of carrier gas at a corresponding time is maintained by controlling the pressure of said carrier gas.

An apparatus for performing a chromatographic separation of a given compound wherein said compound is injected into a pressurized carrier gas and passed through a column and wherein a portion of said column is contained in an oven which subjects the column to a temperature profile, comprising:

• temperature means for generating a temperature information signal representative of the temperature in said oven;
• pressure means for determining the pressure of said carrier gas and for generating a pressure information signal representative of said pressure;
• memory means for storing system information, mass flow information, and carrier gas viscosity information;
• control means for receiving said temperature information signal and said pressure information signal, for retrieving said system information, said mass flow information and said viscosity information from said memory means, for calculating a carrier gas pressure in relation to said system information, said mass flow information and said viscosity information, and for generating a control signal in relation to the calculated carrier gas pressure and said pressure information signal;
• and
• valve means for controlling the pressure of said carrier gas in response to said control signal, so that as the temperature in said oven changes with time, the desired mass flow of carrier gas at a corresponding time is maintained by controlling the pressure of said carrier gas.

An apparatus for performing a chromatographic separation of a given compound wherein said compound is injected into a pressurized carrier gas and passed through a column and wherein a portion of said column is contained in an oven which subjects the column to a temperature profile, comprising:

• pressure means for determining the pressure of said carrier gas and for generating a pressure information signal representative of said pressure;
• memory means for storing desired carrier gas mass flow information and oven temperature information;
• and
• control means for retrieving said mass flow information and said oven temperature information and for controlling the pressure of said carrier gas in response to said mass flow information, said oven temperature information and said pressure information signal, so that as said oven temperature information changes with time, the desired mass flow of carrier gas at a corresponding time is maintained by controlling the pressure of said carrier gas.

An apparatus for performing a chromatographic separation of a given compound wherein said compound is injected into a pressurized carrier gas and passed through a device having a controlled temperature which subjects the carrier gas to a temperature profile, comprising:

• temperature means for generating a temperature information signal representative of the temperature in said device;
• pressure means for determining the pressure of said carrier gas and for generating a pressure information signal representative of said pressure;
• memory means for storing system information, mass flow information, and carrier gas viscosity information;
• control means for receiving said temperature information signal and said pressure information signal, for retrieving said system information, said mass flow information and said viscosity information from said memory means, for calculating a carrier gas pressure in relation to said system information, said mass flow information and said viscosity information, and for generating a control signal in relation to the calculated carrier gas pressure and said pressure information signal.