Analytical reference materials. Part VII. Development and certification of a sediment reference material for total polychlorinated biphenyls

Abstract

A lake sediment reference material naturally contaminated with PCBs was prepared. Subsamples of this material were subjected to repetitive in-house analyses for total PCBs. The quantitative recovery of PCBs was demonstrated by performing ultrasonic and Soxhlet extractions under various conditions. Sample extracts were usually cleaned-up with Florisil and the cleaned extracts were shown to be free from other major interferences, except for sulphur, which was later removed by mercury. The presence of PCBs in the samples was confirmed by the perchlorination of the sample extract and by GC-MS techniques. Most of the sample extracts were quantitated against a 1 + 1 + 1 mixture of Aroclors 1242, 1254 and 1260 on a 3% OV-1 packed column using the technique described by Webb and McCall. These results were further confirmed by the quantitative GC-MS analyses of EC-1 and by interlaboratory results provided by independent laboratories. The reference material showed no signs of degradation of its PCB content over a six-year storage period at –20 °C in the dark.