The determination of chlorinated biphenyls,chlorinated dibenzodioxins,and chlorinated dibenzofurans by GC-MS

High resolution gas chromatography, with mass selective detection, has been used for the analysis of PCB on methyl 50 % octyl polysiloxane (SB 50 Octyl), methyl octadecyl polysiloxane, and a smectic polysiloxane (SB Smectic); and for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans with 1 to 8 chlorine substituents on 100 % cyanopropyl siloxane (SP 2331), smectic polysiloxane (SB Smectic), a new polar stationary phase (DB-Dioxin). The analysis has also been performed by column coupling.     

Adsorption of 2-chlorophenol on Cu2O(1 1 1)-CuCUS: A first-principles density functional study

First-principles density functional theory and a periodic-slab model have been utilized to investigate the adsorption of a 2-chlorophenol molecule on a CuO(1 1 1) surface with a vacant Cu surface site, namely Cu₂O(1 1 1)-Cu_CUS. Several vertical and flat orientations have been studied. All of these molecular configurations interact very weakly with the Cu₂O(1 1 1)-Cu_CUS surface, an observation which also holds for clean copper surfaces and the Cu₂O(1 1 0):CuO surface. Hydroxyl-bond dissociation assisted by the surface was found to be endoergic by 0.42-1.72 eV, depending predominantly on the position of the isolated H on the surface. In addition, the corresponding adsorbed 2-chlorophenoxy moiety was found to be more stable than a vacuum 2-chlorophenoxy radical by about 0.76 eV. Despite these predicted endoergicities, however, we would predict the formation of 2-chlorophenoxy radicals from gaseous 2-chlorophenol over the copper (I) oxide Cu₂O(1 1 1)-Cu_CUS surface to be a feasible and important process in the formation of PCDD/Fs in the post-flame region where gas-phase routes are negligible.     

Separation of polychlorodibenzo-p-dioxins and-dibenzofurans on the new polar stationary phase DB DIOXIN

Summary A complete assignment of the polychlorodibenz-p-dioxins (CL_xDD) and polychlorodibenzofurans (Cl_xDF) (x=4–8) separated on the new polar polysiloxane phase which contains 44% methyl, 28% phenyl, 20% cyanopropyl and 8% polyoxyethylene (Carbowax) groups (DB DIOXIN) is presented.     

A novel CGC-CGC-MS configuration for the analysis of polychlorodibenzodioxins and polychlorodibenzofurans

Summary The analysis of polychlorodibenzodioxins and polychlorodibenzofurans on a novel multidimensional (CGC-CGC-MS) configuration is presented. The system is based on flow controlled column switching, allowing the simultaneous isomeric separation of tetrachloro-, pentachloro- and hexachloro-substituted dibenzodioxins and dibenzofurans on a polar column and the analysis of heptachloro- and octachloro-substituted dibenzodioxins and dibenzofurans on an apolar column. PTV injection in the solvent vent mode allows analysis of large sample sizes approaching in this way the sensitivity of CGC—high resolution MS.Dedicated to Professor Leslie S. Ettre on the occasion of his 70th birthday.