Chromatographic Techniques for Characterization of Coal Tar Pitch Volatiles

Abstract

Although the benzene-soluble fraction (BSF) method has traditionally been used to evaluate exposure to coal tar pitch volatiles (CTPV), it fails to identify any components in the sample. Traditional gas or liquid chromatography techniques used in conjunction with the BSF will measure specific compounds, which constitute only a portion of the total contents of the sample. In this work, three distinct chromatographic techniques for CTPV will be presented: 1) an LC method for calculating total poly cyclic aromatic hydrocarbons (3- to 6-ring); 2) a capillary GC method for identifying and quantifying interference by mineral oil; and 3) a column chromatographic technique for separating PAH from oil on a class basis. A discussion of an unknown fraction commonly found in CTPV samples, but which cannot be measured by traditional chromatographic techniques, will also be presented. Conclusions will be drawn from specific aluminum plant field data as to the composition of CTPV samples, and specific recommendations will be given for correcting the BSF measurement for interfering substances.