Although chlorinated paraffins are widely used and therefore produced in large amounts (about 250 kt/a) — with well known problems —, there is a lack of a selective, highly sensitive and reproducible analytical method for the determination of these substances. Such a method is presented using GC/MS with electron impact ionization for their quantitative determination. The samples, pretreated with conc. sulphuric acid, were cleaned up by solid-phase extraction on alumina, and the chlorinated paraffins were determined by GC/MS using highly selective ion clusters.
By this method, determination limits of 3 ng (corresponding to about 1.5 ppb) were routinely obtained. In contrast to the general methods of maximum signal selection or the selection of molecule ions in mass spectroscopy, the presented approach leads to higher selectivity, less discrimination between different types of chlorinated paraffins and allows to obtain further information on the degree of chlorination.