| Abstrakt: |
A serious limitation in the accurate measurement of steroids by Gas Liquid Chromatography (GLC) results from the difficulty of obtaining a quantitative transfer of samples to the column by the method of fluid injection. By the very nature of the technique only a part of the sample can be used. This poses two problems, the first being the small quantity of steroid present in samples to begin with and the second, the difficulty in measuring the amount of sample which remains behind in the receptacle. The second objection may be overcome by the use of an internal labelled standard. Another problem is the limited volume of fluid that can be used for injection since measurement of early peaks may be impossible with a solvent front which persists for too long. A technique employing dry injection of the whole sample would solve all these problems and this communication describes such a device which has been successfully used for about 1 year in the measurement of plasma progesterone. Other devices have been described but have not come into general use (1, 2, 3, 4, 5, 6). |
