Assessment of occupational exposure to diesel fumes - parameter optimization of the thermal coulometric measurement method for carbon

'Elemental' carbon (EC) is used as a surrogate to assess occupational expos ure to diesel soot. EC thermal analysis needs complete desorption of organi c compounds from the soot particles prior to analysis in order to minimize positive interferences and artefacts. The desorption of the organic compoun ds can be considered as the major step which influences the reliability of the EC determination. A systematic study was carried out to investigate the different parameters of influence such as desorption temperature, desorpti on duration, heating rate and type of the sample on the desorption efficien cy. It was found that temperature and duration are the major parameters of influence on the desorption efficiency. The influence of the sample load ca n be seen as a measure of the pyrolysis susceptibility of the sample. An op timized temperature program is proposed.