F.W. Karasek

Mechanism of formation of polychlorinated dibenzo-p-dioxins produced on municipal incinerator flyash from reactions of chlorinated phenols

All incinerators burning municipal waste produce chlorinated dioxins. The mechanism by which these compounds are formed is unknown. Experiments were performed that show these compounds can be produced from known precursors by surface catalysed reactions on the flyash particulates present in the incineration process. A full range of the tetra- through octachlorinated dibenzo-p-dioxins were produced from 13C-labelled pentachlorophenol and two trichlorophenols on the surface of flyash from an Ontario municipal incinerator that had been previously freed from organic material. A simple flow-tube apparatus at 300 degrees C under a 10-ml/min nitrogen flow was used for the experiments. The use of 13C-labelled pentachlorophenol gave a direct measure of the extent of the catalytic reactivity of the flyash surface. Much lower amounts of chlorinated dioxins were produced in similar experiments with flyash from a modern Japanese incinerator whose effluents are normally extremely low in these compounds. Only small amounts of octachlorodioxin, the thermal condensation product expected, were formed using ground firebrick or an empty flow-tube for the reactive surface. These results indicate that the flyash surface has constituents and properties that promote the production of chlorinated dioxins from chlorinated phenols and support the catalyzed surface reaction mechanism previously proposed.

Identification of organic compounds obtained from incineration of municipal waste by high-performance liquid chromatographic fractionation and gas chromatography-mass spectrometry

Abstract A gradient, normal-phase high-performance liquid chromatographic (HPLC) separation procedure that effectively provides a compound class separation was applied to the analysis of extracts of flyash from municipal incinerators in Ontario, Canada and Oslo, Norway. Each fraction collected from the HPLC procedure was analysed by capillary gas chromatography and capillary gas chromatography-mass spectrometry. More than 200 organic components were identified in the canadian extract. The polychlorinated dibenzodioxins (PCDDs) were exclusively eluted in one fraction, which facilitated their quantitation. The retention indices of some environmentally important polychlorinated organic compounds were determined with an average standard deviation of 0.023. The average recovery of the PCDD compounds in the HPLC separation step was 105% with a relative standard deviation of 6.8%.

Plasma chromatography of heroin and cocaine with mass-identified mobility spectra

Plasma chromatography detects and identifies compounds in trace quantities at atmospheric pressure through characteristic positive and negative mobility spectra. To facilitate use of the technique to detect gas chromatographic effluents, a number of reference mobility spectra for different classes of compounds have been reported. Reference spectra for two more compounds, heroin and cocaine, are presented in this study. The primary ions found in these mobility spectra were determined to be M+, (M - H2)+, and (M - CH3CO2)+ for heroin and M+, (M - C6H5CO2)+ and (M - C6H5CO2 - CO2CH3)+ for cocaine using a directly interfaced plasma chromatograph-mass spectrometer. The identified ions agree closely with those predicted in the ion mobility spectra using mass-mobility correlation data coupled with chemical ionization mass spectrometry data. Also, an independent check demonstrating the reliability of reduced mobility values reported in earlier reference spectra was made.

Plasma chromatography of the monohalogenated benzenes.

Abstract : Using thermal electrons and positive reactant ions from nitrogen gas, both positive and negative plasmagram patterns have been obtained for fluorobenzene, chlorobenzene, bromobenzene, and iodobenzene. The plasmagrams give characteristic qualitative data. Positive plasmagrams show protonated molecular ions containing one and two molecules; the negative plasmagrams, except for the fluorobenzene, show only a strong halogen ion peak, which provides experimental evidence for dissociative electron capture by thermal electrons. (Author)

Products obtained during combustion of polymers under simulated incinerator conditions. II: Polystyrene

Abstract An apparatus permitting the combustion of large (2 g) polymer samples at high temperature is described. Effluents from combustion are collected in cold traps (liquid nitrogen) and on glass wool for analysis by capillary gas chromatography and gas chromatography—mass spectroetry. Products from polyethylene combustion at four temperatures (800, 850, 900, 959°C) are determined.

Detection of 2,4,6-trinitrotoluene vapours in air by plasma chromatography

Abstract Rapid detection and identification of picogram quantities of the vapours of 2,4,6-trinitrotoluene (TNT) and related compounds in air is possible using the technique of plasma chromatography. Operating at atmospheric pressure, the instrument uses either air or nitrogen carrier gas into which the sample is injected directly or through a simple gas chromatographic system. Identification is provided by the characteristic mobility spectra obtained. Both positive and negative mobility spectra for TNT and 2,4-dinitrotoluene are presented and selective detection at ultra-trace levels is demonstrated.

Inhibition of Chlorinated Dibenzo-p-dioxin Formation on Municipal Incinerator Fly Ash by Using Catalyst Inhibitors

Abstract Fly ash-catalysed surface reactions are probably the most important mechanism in the formation of chlorinated dibenzo-p-dioxins (PCDD) and related compounds in municipal incinerators. The introduction of a suitable catalyst inhibitor should decrease the yield and change the distribution of PCDD formed on the fly ash. The addition of catalyst inhibitors containing amino- and hydroxy-functional groups to the fly ash surface greatly inhibited the catalytic activity of the fly ash. 2-aminoethanol and triethanolamine were the most effective catalyst inhibitors. The significance of these results to controlling the emissions of PCDD from municipal refuse incinerators is discussed.

Plasma chromatography of the n-alkyl halides

Abstract A plasma chromatograph directly interfaced to a gas chromatograph functions as a very sensitive qualitative detector for gas chromatographic peaks. Using a nitrogen carrier gas, the plasma chromatograph creates the positive reactant ions (H2O)nH+ and (H2O)nNO+ and the negative reactant species of low-energy electrons to react with the gas chromatographic peak component and form characteristic product ions. Ion mobility spectra observed in the plasma chromatograph for a series of 1-halogenated alkanes from 1-C4H9X to 1-C8H17X display negative spectra consisting of only the halogen ion from dissociative electron capture. The positive mobility spectra appear to contain the (M  1  X)+ as the most abundant ion, along with smaller characteristic ion peaks. These results are consistent with plasma chromatographic spectra obtained in similar studies of halogenated aromatics, alkanes and oxygenated organic compounds.

Decomposition of nitropyrene during gas chromatographic-mass spectrometric analysis of air particulate and fly-ash samples

Abstract 1-Nitropyrene was found to decompose during gas chromatographic-mass spectrometric (GC-MS) analysis. Decomposition was observed both on the column and after the column. The decomposition product was tentatively identified as aminopyrene. Extracts of an air particulate sample and an electrostatically precipitated flyash sample from a municipal incinerator were examined for the presence of 1-nitropyrene. The compound was identified in the air particulate extract at the low ppm level, but was not detected in the fly-ash sample. A stable isotope standard was employed to compensate for the lability of the 1-nitropyrene in the GC-MS system to assure positive identification and quantification of the low levels present in air particulates.

Extraction of organic compounds from airborne particulate matter for gas chromatographic analysis

Abstract Airborne particulate matter was collected on high-volume glass fiber filters for analysis of the organic fraction by gas chromatography-flame ionisation detection and gas chromatography-mass spectrometry techniques. Exhaustive solvent extraction followed by concentration through condensation results in a sample suitable for gas chromatographic analysis. Although cyclohexane is the solvent most commonly used for extracting organic compounds from atmospheric particulate matter, methanol was found to be more effective for this extraction. It extracted more components in larger quantities and in less time than did cyclohexane. The methanol extraction from particulates collected on glass fiber filters appears to be effective for collections of both aliphatic and polycyclic aromatic compounds and organic acids. An inorganic precipitate which forms during the condensation of the methanol extract from 200 ml to 1 ml is removed by centrifugation.