A gas-chromatographic solid state detector based on Tin oxide semiconducting gas sensor

A prototype solid state detector (SSD) for capillary gas-chromatography was realised using an experimental tin oxide thin film gas sensor. This SSD prototype was designed for ambient temperature operation, so it is suitable for the analysis of low boiling point organic compounds. The sensor was mounted in a glass chamber (1.2 ml) and installed on a GC/FID system equipped with a PLOT column. The chromatographic column outlet was symmetrically split between the SSD and the FID. The SSD was supplied with a stream of GC grade air mixed with the column effluent gas immediately upstream the detector chamber. The SSD was tested with ethane, propane, ethylene and acetylene injections. The SSD response was evaluated measuring the sensor conductance shift versus time. The relative sensitivity of SSD was ethane < propane << ethylene < acetylene as it may be expected from a device based on catalytic combustion reactivity. The width of the chromatographic SSD peaks was measured at different sensor temperatures and compared with the FID peaks width. This SSD detector implementation demonstrates the ability to detect 21 pg of acetylene.