US 6,955,709 B2 · Method and device for vaporization injection of high volumes in gas chromatographic analysis

Abstract

This invention concerns a method and apparatus for vaporization injection of large volumes of liquid sample (substance to be analysed+solvent) introduced by a syringe needle into a heated vaporization chamber which is part of an injector coupled operatively to a device for gas chromatographic analysis. The sample is sent in the form of a liquid band traveling through the vaporization chamber at high speed until it reaches a stopping and vaporization device positioned adjacent to the inlet of a capillary to collect the vapors. In order to inject large volumes without modifying the vaporization chamber and without partial losses of the samples, the sample vapors, in splitless mode, are drawn up from the vaporization chamber into the capillary by virtue of the local action of volume contraction caused by recondensation of at least the solvent vapors in the capillary.

Claims17

Dependent claims

A method for vaporization injection of large volumes of liquid sample having a substance to be analysed and a solvent, said method comprising the steps of:

introducing the liquid sample by means of a syringe needle into a permanently heated vaporization chamber which is part of an injector having an inlet for a carrier gas coupled operatively to a device for gas chromatographic analysis;
causing the sample to travel through said vaporization chamber as a liquid band at a high speed;
bringing the liquid band traveling at said high speed into contact with a stopping and vaporization means positioned adjacent an inlet of a capillary to thereby collect sample vapours therefrom, and wherein
the method is practiced in a splitless mode and the capillary is in the form of a pre-column maintained at a sufficiently low temperature below a dew point of a mixture of the sample vapours and carrier gas at a carrier gas pressure which results in recondensation of at least the solvent vapours in the pre-column to cause the sample vapours to be drawn up from the vaporization chamber and into said pre-column.

1 more element

A device for gas chromatographic analysis of samples having a substance to be analysed and a solvent, wherein sample injection is performed in splitless mode, said device comprising a vaporization type injector, an oven, a gas chromatographic column housed in the oven, and a detector, wherein the injector comprises,

a heated chamber which includes a septum, said septum being capable of penetration by a syringe needle for fast injection of the sample in the form of a liquid band,
a duct for feeding carrier gas into the injector,
a capillary having an inlet for receiving sample vapours,
a separation column coupled operatively to the capillary, and
stopping and vaporization means positioned in the chamber for the stopping and vaporizing the liquid band of the sample adjacent to the inlet of the capillary to thereby collect the vapours and send the vapors to the separation column, wherein
said capillary is in the form of a pre-column positioned between the injector and the separation column, and wherein
said device comprises means for maintaining said pre-column, during sample injection, at a temperature below a dew point of a mixture of the sample vapours and carrier at a carrier pressure which results in recondensation of at least the solvent vapours in the pre-column to thereby responsively cause the sample vapours to be drawn up from the vaporization chamber.

4 more elements

Dependencies are inferred from the claim text.

Method and device for vaporization injection of high volumes in gas chromatographic analysis

Life of this patent

Method and device for vaporization injection of high volumes in gas chromatographic analysis

Life of this patent

Abstract

Claims17