Loss of Polychlorinated Dibenzo-p-dioxins, Polychlorinated Dibenzofurans and Coplanar Polychlorinated Biphenyls during Vacuum Concentration for Ultra-trace Analysis

摘要

We investigated the effectof kinds of organic solvent on the losses of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs), coplanar polychlorinated biphenyls (Co-PCBs), and their 13C12-labeled compounds during vacuum concentration. n-Hexane and toluene solutions containing the standards of those compounds were tested for the purpose. The kind of organic solvent has remarkable effect on the loss of 13C12-Co-PCBs from the standard solutions, while it has littleor no effect on the losses of Co-PCBs, PCDD/DFs, and 13C12-PCDD/DFs from the standard solutions. The losses of lower chlorinated "Co12-C0-PCBs with w-hexane solution were greater than theloss of the compounds with toluene solution. The relative PCBs with w-hexane solution were greater than theloss of the compounds with toluene solution.The relative amounts of 13C１2-Co-PCBs in the condensate solvent produced during the vacuum concentration show that those of the compounds with toluene solution were less than that of n-hexane solution. These results demonstrate that the minimization of loss of the compounds with n-hexane solution may be achieved by adding toluene before the vacuum concentration. We also examined the relationship between the relative amounts of Co-PCBs and 13C12-Co-PCBs in the condensate solvents and vapor pressures of those compounds. amounts of Co-PCBs and 13C12-Co-PCBs in the condensate solvents and vapor pressures of those compounds. amounts of Co-PCBs and 13C12-Co-PCBs in the condensate solvents and vapor pressures of those compounds. There was the difference in the regression line slopes of the relativeamounts vs. in the vapor pressures between the n-hexane solution and toluene solution. This fact could be useful for the optimization of the vacuum concentration conditions in the convenient analytical methods.