Use of a programmed temperature injector for on-line reversed-phase liquid chromatography-capillary gas chromatography

A simple procedure is described that allows on-line reversed-phase liquid chromatography-gas chromatography (LC-GC); the procedure involves solvent split elimination using a programmed temperature vaporizer (PTV) packed with a suitable trapping material. Eight experimental variables affecting the PTV transfer of the LC fractions into the GC system are evaluated, and conditions adequate for the analysis of various sterols are established. The proposed procedure does not require a phase switching interface (i.e., an on-line transfer of the analytes from the aqueous phase to an organic phase prior to transfer), thus the experimental setup generally required for on-line reversed-phase LC-GC is simplified. The system allows direct analysis of sample volumes up to 1600 μL with injection speeds up to 1500 µL/min. Relative standard deviations less than 10.5% are obtained even though different glass liners are used for the experimental measurements.Peer reviewe