Flow-field-induced temperature gradient gas chromatography
OwnerPeter Boekerinventor
Life of this patent
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Abstract
The invention relates to a method, to a device, and to the use of a method for the gas-chromatic separation and determination of volatile substances in a carrier gas by means of a chromatographic separating capillary (1), wherein the separating capillary and/or an enveloping capillary (2) surrounding the separating capillary (1) is electrically conductive and is heated with current in the form of a resistance heater and is cooled by a forced convective flow by means of a fluid in the form of a gradient flow field in such a way that a continuous temperature gradient arises over the length of the separating capillary.
Claims15
A temperature gradient gas chromatographic (TGGC) method for a gas-chromatic separation and determination of volatile substances in a carrier gas by means of a chromatographic separation capillary,
- wherein the separation capillary and/or a sheath capillary surrounding the separation capillary is/are electrically conductive and is/are heated with current in the form of resistance heating while the substances to be analyzed are carried through the separation capillary by means of a carrier gas,
- wherein the heated separation capillary and/or a sheath capillary is/are selectively cooled by application of a forced convective radial incident flow during the separation phase, the forced convective radial incident flow being blown radially with respect to the heated separation capillary and/or a sheath capillary surrounding the separation capillary by means of a fluid generated in a unit for producing the forced convective radial incident flow,
- thereby controllably generating a gradient of a flow speed of the forced convective radial incident flow around the separation capillary and/or sheath capillary surrounding the separation capillary during the separation phase and producing directly at and in the resistance-heated separation capillary and/or the sheath capillary stable equilibrium temperatures dependent on the flow speed of the forced convective radial incident flow to the separation capillary and/or the sheath capillary surrounding the separation capillary,
- wherein the equilibrium temperatures are a result of a local thermal balance equilibrium between heat energy supplied to the resistance-heated separation capillary and/or a sheath capillary, heat dissipation by the forced convective radial incident flow and heat radiation of the resistance-heated separation capillary and/or the sheath capillary,
- thus creating a continuous temperature variation in the form of a gradient along the separation capillary and/or the sheath capillary and a temperature drop between an inlet and outlet of the resistance-heated separation capillary and/or the sheath capillary.
Dependencies are inferred from the claim text.