Patent ID: 6055845
Filing Date: 2000-05-02
Classification: G01N

Abstract:
Method for applying samples to be analyzed by gas chromatography using a sampling tube, the substances to be analyzed of the sample being adsorbed by an adsorbing agent arranged in the sampling tube and the sampling tube being inserted into a thermal desorption device of a gas chromatograph for desorbing the substances to be analyzed, the method comprising the steps of:a) utilizing a sampling tube which has an inlet side with a first section which contains the adsorbing agent extending across the cross-section of said first section, the sampling tube narrows essentially conically to an outlet side with a narrowed second section with a bore which has a reduced diameter and is free of the adsorbing agent and has a reduced diameter, the sampling tube configured such that when a gas is guided from the inlet side towards the outlet side, the flow velocity of the gas at the narrowed second section on the outlet side is substantially the same or greater than the velocity of the gas at the first section;b) guiding a liquid or gaseous starting sample material, in particular in the form of an aqueous liquid or an essentially liquid-vapor-saturated gas phase, through the sampling tube from the inlet side towards the narrowed second section, so that substances to be analyzed are adsorbed on the adsorbing agent;c) flushing the sampling tube with drying gas through the sampling tube in the same direction as the starting sample material, until the liquid phase, which is contained in the sampling tube, or the starting sample material is substantially removed; andd) introducing through the sampling tube from the outlet side a carrier gas whereby the adsorbed sample is desorbed.