Determination of polychlorinated dibenzo-p-dioxins and dibenzofurans in commercial pentachlorophenols by combined gas chromatography-mass spectrometry.

Samples of commercial pentachlorophenol (PCP) and its sodium salt (PCP-Na) were examined for the presence of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), using a rapid, highly specific method of analysis. Phenolic compounds are removed by alkaline extraction, and the neutral components are fractionated on an alumina minicolumn. After gas chromatographic separation, individual PCDDs and PCDFs are detected by mass fragmentography and their presence is confirmed by complete mass spectral analysis. While some samples had only low amounts of PCDDs and PCDFs, others contained much higher amounts of these components. PCP-Na samples showed the unexpected presence of a tetrachlorodibenzo-p-dioxin. Re-analysis of PCP and PCP-Na samples with high PCDD contents on a high-resolution glass capillary column showed the presence of 3 hexa- and the 2 heptachlorodibenzo-p-dioxins with nearly constant isomeric ratios.