Validated extraction and cleanup procedures for polychlorinated biphenyls and DDE in human body fluids and infant formula.

As part of an epidemiology study, extraction methods and extract cleanup procedures were developed and validated for polychlorinated biphenyls (PCBs) and DDE, an ubiquitous metabolite of DDT, in human milk, blood serum, and infant formula. Studies included quantitative and reproducible recovery of total lipids, and reproducible and reasonably high recoveries of these chlorinated compounds from the human body fluids and infant formula, including levels of environmental health interest. An extensive quality control and assurance program was designed for use with these methods. Some validation work on serum was done using radiolabeled 14C-Aroclor 1254. Dilution assays were developed to permit use of a constant procedure, which should minimize variability in results. Methods are based on selected organic solvent extraction and column chromatographic cleanup techniques and quantitation by electron capture gas chromatography (EC/GC). Using these extensively researched extraction and cleanup methods, the limits of detection for GC measurements were 10.0 and 2.00 ppb for PCBs and DDE, respectively, in milk and 4.00 and 0.80 ppb in serum.