Quantitative determination of individual chlorinated biphenyls in milkfat by splitless glass capillary gas chromatography.

A method is described for determining individual polychlorinated biphenyls (PCBs) in milkfat at the ppb level. Extraction and major cleanup are done simultaneously by saponification of the milkfat. After final cleanup on basic alumina, the concentrated extract is injected under splitless conditions on a capillary column coated with CPSil 7 stationary phase. The recovery of several individual PCBs from milkfat at a level of 25 ppb is better than 80%. The reproducibility for duplicates analyzed on several days showed standard deviations from 0.2 to 0.9 ppb for 19 individual chlorinated biphenyls. Some preliminary results for 165 samples of milkfat are reported.