Polychlorinated Biphenyls: Congener-Specific Analysis of a Commercial Mixture and a Human Milk Extract

On the basis of the relative retention times and response factors of all 209 synthetic polychlorinated biphenyls (PCBs), this paper reports the first congener-specific analysis of a commercial PCB preparation, Aroclor 1260, and the PCB composition of a human milk extract. The analysis indicates that Aroclor 1260 contains nearly 80 different PCB congeners with the major components identified as 2, 2', 3, 4', 5', 6-, 2, 2', 4, 4', 5, 5'-, 2, 2', 3, 4, 5, 5’-, and 2, 2', 3, 4, 4', 5'-hexachlorobiphenyl and 2, 2', 3, 3', 4, 4', 5-, 2, 2', 3, 3', 4, 5, 6'-, 2, 2', 3, 4, 4', 5, 5'-, and 2, 2', 3, 4', 5, 5', 6-heptachlorobiphenyl. In contrast, the major PCB components of the human milk fraction were the 2, 4, 4’-tri-, 2, 4, 4’, 5-tetra-, 2, 2', 4, 4’, 5-penta-, 2, 3', 4, 4’, 5-penta-, 2, 2', 3, 4, 4, 5’-hexa-, 2, 2, 4, 4', 5, 5’-hexa-, 2, 2', 3, 3', 4, 4', 5-hepta-, and 2, 2', 3, 4, 4’, 5, 5’-heptachlorobiphenyls. The significance of congener-specific PCB analysis is discussed in terms of the structure-activity effects on PCB persistence, bioaccumulation, and toxicity.