Investigation of membrane dryers and evaluation of a new ozone scrubbing material for the sampling of organosulphur compounds in air

The applicability of two different types of Nafion membrane dryers (based o n counter-current flow and desiccant drying) and of a new ozone scrubbing m aterial, polyphenylene sulphide wool (noXon-S), to adsorptive sampling of s elected volatile sulphur compounds (methanethiol, dimethyl sulphide, isopro panethiol and isobutanethiol) is investigated at the low ppb (v/v) level (1 -5 ppb). No analyte losses occur with either type of dryer at relative humi dities (RH) of less than or equal to 50%, while at higher RH values particu larly the thiols tend to be lost (between 6 and 32%) even after conditionin g, The actual losses depend more on the state of the individual permeation membrane rather than on the type of dryer. NoXon-S is a highly suitable ozo ne scrubber material for sulphur compounds since it efficiently removes ozo ne without retainment of the analytes and without the formation of blanks o r artefacts from the scrubber material. The combined use of a Nafion membra ne dryer and a noXon-S ozone scrubber is thus recommended for artifact-free sampling of sulphur compounds. (C) 1999 Elsevier Science B.V. All rights r eserved.