The palladium/silver membrane focusing injector - A new inlet system for thermal desorption capillary gas chromatography

A new sample focusing technique for capillary gas chromatography is described. The system is designed as a focusing inlet for thermally desorbed gas samples. A solid-sorbent trapped sample is thermally released from the sample tube, transferred to a palladium/silver membrane chamber by a hydrogen carrier gas stream and retained there by the gas separation membrane, which is highly permeable to the carrier gas. After focusing in the membrane chamber the sample is injected onto the separation column. This technique allows focusing and injection of highly volatile compounds in capillary gas chromatography without using any coolant. The injection performance for n-alkanes is shown to be comparable to the cryofocusing technique.