技术交流

First GC Separation of 2,3,4,7,8-Pentachlorodibenzofuran from Other Potential Interfering Congeners Performed on a Non-Cyano Stationary Phase: The Rtx-Dioxin2

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/

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技术交流

DB-225, SP-2330, SP-2331 GC Columns Not Needed for 2,3,7,8-Tetrachlorodibenzofuran Isomer Specificity in EPA Methods 1613 and 8290a

April 23rd, 2012 by Jack Cochran I’ve started to wonder if some analysts are taking the language in EPA Methods 1613 and 8290a for high resolution GC – high resolution mass spectrometry of chlorinated dioxins and furans too literally when it comes to confirmatory analysis for 2,3,7,8-tetrachlorodibenzofuran (2378 TCDF), which cannot be done on the DB-5 (5% diphenyl – 95% dimethyl polysiloxane) column suggested for primary analysis.  I’ve copied the language for the methods below, but in summary they recommend either 50% cyanopropyl methyl – 50% phenyl methyl or 90% biscyanopropyl – 10% phenyl cyanopropyl stationary phases that have very low maximum operating temperatures (240-275°C), not good for chlorinated dioxin/furan analysis, especially if you want to keep them in the same GC ove

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