On-column capillary gas chromatographic injector

Abstract

Apparatus and method for injection of samples directly onto a column in a gas chromatograph with injection occurring in a temperature controlled zone outside the oven. The apparatus combines a guide means and valve assembly in alignment with an injection and thermal transfer assembly. In the guide means and valve assembly a radial seal engages the injection means to seal the injection volume, thereby eliminating back flash. In the injection and thermal transfer assembly the capillary column is centered and held in fixed position within a duct means. Means is provided to lower the temperature of the capillary column to a temperature below the vaporization temperature of the liquid sample prior to injection. After injection, means is further provided to raise the temperature of the capillary column to a temperature above the volatilization temperature of the liquid sample to vaporize it and pass it into the capillary column. The method of on-column injection of the present invention comprises inserting an injection means through a radial seal means to a point just above a valve, opening the valve, further inserting the injection means through the valve and into the end of that portion of the capillary column within the thermal transfer assembly and outside the oven of the gas chromatograph, injecting a liquid sample into the end of the capillary column while maintaining the column at temperature below the vaporization temperature of said liquid sample, withdrawing the injection means from the capillary column and the valve means, closing the valve means, withdrawing the injection means through the injector duct and the radial seal means, and heating said column within said temperature controlled zone to volatilize said sample and pass it into said column.

Dependencies are inferred from the claim text.