BASIC EXPERIMENTAL STUDIES ON THE OPERATION OF PHOTOIONIZATION DETECTORS

Commercially available and self-made photoionization detectors have be en studied in a simple flow manifold without chromatographic column. T he self-made detector allowed the independent variation of the detecto r volume, the electrode surface area and a selective irradiation of th e anodes and cathodes. The photoionization of ethanol and acetone has been measured in hydrogen as carrier gas. All experimental results wer e consistent with a model based upon a photoionization proceeding in t he adsorption layer of the electrodes as the main signal generating pr ocess. It has been shown that the photoionization of molecules in the gas phase plays only a marginal role.