G.W. Sovocool

Correlation of structure with retention index for chlorinated dibenzo-p-dioxins

The method presented here allows calculation of the retention indices for the chlorinated dibenzo-p-dioxins under a specific set of experimental conditions, using a limited data set. This technique provides a simple way to obtain retention index data for those isomer standards not readily available. Thus, the technique can aid in structure assignment of specific congeners whether obtained from synthesis or found in environmental monitoring efforts. These calculations have proved highly successful in checking gas chromatographic retention data for internal consistency.

Analysis of municipal incinerator fly ash for bromo- and bromochloro-dioxins, dibenzofurans, and related compounds

Abstract An intensive investigation was made of the organic components of a representative fly ash sample from a municipal incinerator. The sample was analyzed using U.S. EPA RCRA Method 8280 incorporating both low and high resolution mass spectrometric techniques. Brominated and bromochlorinated analogs of polycyclic aromatic hydrocarbons as well as bromochlorinated dibenzodioxins and dibenzofurans were detected in this municipal incinerator fly ash sample.

Bromo- and bromochloro-dibenzo-p-dioxins and dibenzofurans in the environment

At least 36 million pounds of brominated flame retardants are used in the U.S. annually. Most if not all of these materials enter the waste stream via landfilled plastic waste, municipal incinerator fly ash, or automotive fluff waste. Analytical methodology is summarized which is suitable for environmental monitoring of these wastes, and the significance of the analytical results is discussed.

Electrophilic bromination of dibenzo-p-dioxin

Abstract Dibenzo- p -dioxin has been brominated under standard electrophilic conditions to yield mono- through octabromodibenzodioxin. The GC retention indices (RI) for thirteen products have been measured and correlated with the retention indices calculated for the corresponding chlorodibenzodioxins. Mass spectra for the eight major congeners are reported. Brominated dibenzodioxins (PBDDs) may be widely dispersed in the environment, arising from oxidative ring closure of fire retardant brominated diphenyl ethers, combustion of other bromine containing materials, from the use of brominated phenols as synthetic intermediates, and other routes analogous to the formation of the polychlorinated dibenzodioxins (PCDDs). In order to monitor possible environmental contamination by highly toxic PBDDs, authentic analytical chemical standards of these compounds must be available. We wish to report the synthesis of certain congeners of mono-through octa-PBDDs, mass spectral characteristics and retention indices for these compounds. The retention indices for these compounds were found to correlate well with the calculated and observed values of the PCDDs. We have recently developed a model which correlates retention index with structure and provides a simple method to calculate the RI for the PCDDs. This correlation was used to assist in assigning structures while minimizing potential human exposure to these materials.

Correlation of structure with linear retention index for bromo- and bromochlorodibenzo-p-dioxins and bromodibenzofurans

Abstract A model-correlating structure with gas chromatographic retention index was developed to assist in making positional isomer assignments for dioxins halogenated by bromine and/or chlorine using commercially available standards and synthetic mixtures. Bromodibenzofuran assignments were made using pyrolysate mixtures, assuming the elution order was the same as for chlorinated dibenzofurans. These strategies can be used, on an interim basis, for isomer assignments in environmental monitoring efforts.

Electrophilic bromination of dibenzofuran

Abstract Dibenzofuran has been brominated under standard electrophilic conditions to yield mono- through octabromodibenzofuran. The GC retention indices for ten products have been measured and correlated with the retention indices for the corresponding chloro dibenzofurans. Mass spectra for the eight major products are reported.

Improvements to method performance for environmental monitoring of dioxins and dibenzofurans

Abstract Relative efficiencies of various sample preparation techniques were measured for analysis of chlorinated dioxins and dibenzofurans (PCDD, PCDF) in representative wastes. The following sample cleanup columns were tested: a mixed phase column of acid, base, and neutral silica; neutral and acidic alumina columns; Carbopack/Celite and AX-21 carbon adsorption columns. Chlorinated dioxins and dibenzofurans were analyzed in fly ash, still bottom, fuel oil, and sludge matrices for this study. The multi-phase silica, acidic alumina, and AX-21 columns were determined to be the most suitable combination for PCDD and PCDF analytes.

Preparation of bromochlorodibenzo-p-dioxins and dibenzofurans and analysis by EPA RCRA method 8280

Abstract Dioxin and dibenzofuran standards containing both bromine and chlorine substituents have been prepared. Standard mixtures have been spiked into an artificial soil matrix and successfully analyzed by the EPA-RCRA Method 8280. Criteria are proposed for confirming their presence in environmental samples.

Synthesis of polyhalogenated dibenzo-p-dioxins

Abstract Bromochlorophenols have been prepared by catalytic bromination of commercially available chlorophenols. The corresponding bromochloro potassium phenolates have been condensed under Ullmann conditions to yield bromochlorodibenzo- p -dioxins. Products are assigned structures based upon the structure of the starting phenol, mass spectrometry, statistical analysis of the reaction pathways and GC retention time.

Mass spectral characteristics of bromochlorinated dibenzo-p-dioxins and dibenzofurans

Abstract Dibenzo- p -dioxins and dibenzofurans containing both chlorine and bromine substituents are known to be constituents of municipal incinerator fly ash. This report presents analytical confirmation criteria for these compounds based upon GC/MS parameters. Mass spectra of 26 representative analyte classes are tabulated for reference.