title: Evaluation of Column Cleanup for Chlorobenzenes, Polychlorinated Biphenyls, Polychlorinated Dibenzo-p-dioxins, and Polychlorinated Dibenzofurans in MM5 Flue Gas Analysis.
abstract: The recoveries of chlorobenzenes (CBs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) from the acid-base-on-silica column (ABS), the silver nitrate-on-silica column (SNS), and the alumina column (ALM) were investigated using eluents with various concentrations of dichloromethane in hexane. PCBs recoveries from the ABS and ALM columns are generally increased with increasing number of chloro substituents. However, PCBs recoveries are also complicated by the inductive and resonance contributions due to the different conformation and electron density of the congeners. The recoveries of PCBs with lower number of chloro substituents decreased with increasing silver nitrate content coated on silica. With 2% dichloromethane in hexane (as normally used in MM5 analysis), the recoveries of all CBs and trichloro- to decachlorobiphenyls from ABS, 10% SNS, and ALM columns in series are ≥80%. However, the 2,4-dichlorobiphenyl is only 16% recovered, and monochlorobiphenyls are not recovered at all. Under these conditions, the recoveries of PCDDs/PCDFs from ABS and 10% SNS columns in series are ≥80%. With 60% dichloromethane in hexane, PCDDs/PCDFs recoveries from ALM column are ≥80%. The implication of the selective adsorption of PCBs on the fractionation of CBs/PCBs and PCDDs/PCDFs from these MM5 cleanup columns is discussed.
authors.affiliation: Alberta Research Council Vegreville, P.O. Bag 4000, Vegreville, Alberta, Canada T9C 1T4.
authors.forename: L K
authors.initials: LK
authors.lastname: Tan
authors.forename: A J
authors.initials: AJ
authors.lastname: Liem