April 20th, 2012 by Jack Cochran I just presented a lecture in Venice at the 7th International POPs Symposium sponsored by Thermo Scientific and showed the first ever, to my knowledge, GC separation of 2,3,4,7,8-pentachlorodibenzofuran (23478 PeCDF) from any interfering congeners on a non-cyano stationary phase, the Rtx-Dioxin2.  Although 2,3,7,8-tetrachlorodibenzodioxin (2378 TCDD) and 2,3,7,8-tetrachlorodibenzofuran (2378 TCDF) get most of the press because of their toxicity and presence in biota samples, 23478 PeCDF also has high toxicity (TEF = 0.3) and can dominate the overall toxicity of some samples, especially those where the contamination is from particular chloralkali processes. EPA Methods 1613 (Tetra- through Octa-Chlorinated Dioxins and Furans by Isotope Dilution HRGC/