Multidimensional separation of isomeric species of chlorinated hydrocarbons such as PCB,PCDD, and PCDF

A multidimensional GC-system containing two capillary columns of different polarities, operated within a double oven instrument, was used for the optimized separation of complex isomeric mixtures of various types of chlorinated aromatic compounds such as PCB, PCDD, or PCDF. Electron capture was applied parallel to flame ionization detection to obtain sensitive signals of the PCB or PCDD and the n-alkane standards required for identification by Kovats indices, respectively. Electron capture detection within a valvelessly operated MDGC system forced changes in the usual instrumental set-up, the live-switching coupling piece being located within the second oven of the double oven instrument. This oven is operated isothermally to ensure optimal and interference-free detection, for stable flow conditions within the coupling piece and for the determination of the isothermal retention indices (Kovats), which are much more suitable for identification by retention than the so-called “linear” indices.     

Diurnal, weekly and seasonal air concentrations of PCDD and PCDF in an industrial area

Summary Air samples were collected in an industrial area close to Milan in July and in November, day and night for five days and have been analyzed for PCDD and PCDF. Average summer levels were generally lower than winter levels, and average concentrations were higher by night than by day in both months.     

Biomarkers and bioassays as alternative screening methods for the presence and effects of PCDD, PCDF and PCB

Summary Polyhalogenated aromatic hydrocarbons (PHAH) are wide spread, highly toxic, environmental contaminants. As such they pose risks for both humans and wildlife. For risk assessment purposes, concentrations are generally analyzed by HRGC-HR/LRMS. With the analytical data, mixture toxicity is calculated using the TEF concept. With this method only the defined congeners are taken into account and additivity for all congeners is assumed, whereas synergistic and antagonistic effects for several PCDD/F in combination with PCB have also been reported. To avoid these problems and high analytical costs, bioassays can be used for screening purposes. Cytochrome P450 1 A 1 induction and vitamin A and thyroid hormone levels are shown to be useful markers for PHAH exposure. When bioassays based on cytochrome P450 1A1 induction, in cultured cells, in multi-well culturing plates, are used, 2,3,7,8-TCDD detection limits <0.2 pg are possible. As such these bioassays are highly sensitive, cost effective and time saving. This application can be used as a pre-screening method to determine total dioxin content of environmental samples.     

Evaluation of an automated clean-up system for the isotope-dilution high-resolution mass spectrometric analysis of PCB, PCDD, and PCDF in food

An automated clean-up system was evaluated for the simultaneous analysis of polychiorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and biphenyls (PCB) in different foods. In addition to the seventeen 2,3,7,8-substituted PCDDIPCDF and four non-ortho PCB, by use of the clean-up system studied, it was possible to collect the eight mono-ortho and two di-ortho PCB and the seven indicator PCB in two separate fractions during the same clean-up run. The study was first performed using standard mixtures containing PCDD, PCDF and PCB, and a certified reference material. The recoveries of the 13C-labeled compounds ranged from 51 to 90%, indicating that the PCDD, PCDF, and PCB clean-up worked satisfactorily. Next, the automated system for PCDD, PCDF, and PCB analysis was evaluated for foods such as milk, egg, meat (beef, chicken, and pork), mussel, and olive oil. The recoveries of the 13C-labeled compounds ranged from 40 to 120% for PCB and from 57 to 113% for PCDD/ PCDF, meeting the requirements of well accepted methods. Thus, the automated clean-up system studied is a suitable alternative to conventional clean-up methods.     

Determination of PCDD/PCDF in motor oil and air particulates. A modular approach in clean-up

Summary In trace analysis of the polychlorinated dibenzodioxins (PCDD) and -furans (PCDF) simple adsorption Chromatographic procedures for matrix removal are shown to be highly successful. In the case of a complex matrix a combination or even a repetition of different separation steps is necessary. The independent, flexible combination of separation steps (modular approach) makes it possible to find the optimum conditions for the removal of extremely divergent matrices in an easy way. A combination of classical separation steps in organic trace analysis has been successfully applied to the investigation of used motor oil and urban particulates: hexane/DMF partition, adsorption chromatography on various adsorbents (silica, alumina, Mg-silicate) as well as the extractive digestion procedure with concentrated sulfuric acid. In this way it became possible to inject the mass equivalent of 3 g of oil in HRGC/ MSD-analysis.

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Bestimmung von PCDD und PCDF in Motorenöl und Straßenstaub. Ein modularer Ansatz für die Matrixabtrennung

     

PCDF and PCDD levels in different types of environmental samples in spain

Summary A study has been carried out of the presence and levels of PCDFs/PCDDs in a series of typical samples including those from municipal waste incinerators (fly ashes, slag and emissions), paper mill effluents and leachates from municipal and industrial landfills. The samples were collected at different places in the northeast of Spain; the results obtained are comparable to those reported in the literature.     

Intercomparison study on milk powder fortified with PCDD and PCDF

Summary In order to find out the state of the art of dioxin analyses in cow's milk the BCR has organised an intercomparison in native and fortified milk-powders. The preparation of the milk-powder batches is described. Laboratories (n=11) have used their own in-house methods and standards. The use of a high resolution MS (R=10 000) was requested. An outline is given of how the results obtained were interpreted in discussions with the participants. A major problem in the quantification is the lack of certified standard solutions of all seventeen 2,3,7,8 congeners, this was shown during the analysis of the BCR standard solution. Recovery of the fortified dioxins from the milk-powders were in general between 80–90% of the added values. A further problem was the analysis of hepta and octa chlorinated congeners; for the calculation of international toxicological equivalent quantities (I-TEQ), larger variations in these did not significantly affect the total I-TEQ in milk-powder. Most of the participants were able to deliver satisfactory results for judging the acceptability of the milk for human consumption.     

Improvements in GC/MS strategies and methodologies for PCDD and PCDF analysis

Summary The analysis of polychloro-p-dibenzodioxins (PCDD) and polychlorodibenzofurans (PCDF) on a new non-polar column, DB-5ms, is reported. This new 5% phenyl column exhibits identical inertness, sensitivity, stability and capacity to DB-5 for PCDD and PCDF but provides better separation for some toxic 2,3,7,8 substituted congeners. Linear response for labelled and unlabelled toxic congeners is easily obtained over the range from 0.5 pg to 200 ng for 2,3,7,8-TCDD.     

Updating the UNICHIM method for the determination of PCDD and PCDF in waste incineration plants

Summary The UNICHIM method developed in Italy for the determination of PCDD and PCDF emitted from waste incineration plants is presented. Based on the experience gained during the last four years, some modifications are proposed in order to render this analytical tool adequate for present and future needs.     

A polymeric liquid crystal capillary column for GC-MS analysis of PCDD and PCDF

A newly developed side chain liquid crystal polysiloxane has been investigated as a stationary phase for the isomer-specific analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans substituted at positions 2, 3, 7, and 8. The retention times from the chromatograms of a standard solution containing all PCDD and PCDF isomers were compared with those from solutions containing only those tetra- to octa-chlorinated compounds substituted at positions 2, 3, 7, and 8. In general, PCDDs substituted at positions 2, 3, 7, and 8 eluted later than most other isomers of the same congener group. The separations obtained on this stationary phase were compared with those obtained elsewhere using a commercially available product.     

An improved clean-up strategy for simultaneous analysis of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and polychlorinated biphenyls (PCB) in fatty food samples

The study and extension of a simple automated clean-up method for polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) to a broad range of polychlorinated biphenyls (PCB) is described. The isolation of seven PCDD, ten PCDF, and three coplanar PCB (cPCB) is extended to eight monoortho substituted PCB and seven so-called "marker PCB" (Aroclor 1260) for fatty food samples. This enables quantification of 35 compounds - including all congeners with a WHO toxic equivalent factor (TEF)--in a single extraction and single purification step. The chromatographic behaviour of mono-ortho PCB and marker PCB on a variety of adsorbents, including basic alumina, has been studied. Partitioning of analytes through multi-column sequences is described and correlated with their structural and electronic properties, by use of molecular modelling calculations. The fractionation process available with the Power-Prep automated clean-up system enables rapid independent analysis of the different groups of compounds. Gas chromatography with high resolution mass spectrometry (GC-HRMS) is used for the PCDD/F and cPCB fraction and quadrupole ion-storage tandem in time mass spectrometry (GC-QISTMS) for analysis of the remaining PCB. A comparison study was performed on quality-control samples and real fatty food samples to evaluate the robustness of the new strategy compared with a reference method. On the basis of this simultaneous clean-up, a rapid simplified strategy for PCDD/F and selected PCB analysis determination is proposed for fatty food samples.     

PCDD/PCDF formation and destruction during co-firing of coal and RDF in a slag forming combustor

Summary Environmental aspects related to the co-firing of pulverized coal and RDF (refuse derived fuel) in a slag forming combustor have been investigated with regard to specific combustion parameters and fuel type. Three classes of organic micropollutants have been considered: PCDD (polychlorodibenzodioxins), PCDF (polychlorodibenzofurans) and PAH (polycyclic aromatic hydrocarbons). The emissions from coal/RDF combustion (40% RDF) have been compared with those from the plant fired with pulverized coal alone. In order to follow the thermal and oxidative history of the investigated organic compounds, samples of flue gases were collected at the exit of the slagging combustor but before the boiler entrance, and at the boiler outlet stack.     

Statistical quality control of PCDD/PCDF analysis using a total measuring data set

 A random error and accuracy estimation approach for polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) analysis is presented based on statistical treatment of all the data set registered in a run or in a bunch of uniform runs. Received: 18 August 1998 / Accepted: 21 October 1998     

Studying variations in the PCDD/PCDF profile across various food products using multivariate statistical analysis

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are widely recognized by the scientific community as persistent organic pollutants due to their toxicity and adverse effects on wildlife and human health. The actual regulation dedicated to the monitoring of dioxins in food is based on the measurement of 17 congener concentrations. The final result is reported as a toxic equivalent value that takes into account the relative toxicity of each congener. This procedure can minimize the qualitative information available from the abundances of each PCDD/PCDF congener: the characteristic contamination profile of the sample. Multivariate statistical techniques, such as principal component analysis (PCA) or linear discriminant analysis (LDA), represent an interesting way to investigate this qualitative information. Nevertheless, they have only been applied to the analysis of contamination data from food products and biological matrices infrequently. The objective of the present study was to analyze a large data set from dioxin analyses performed on various food products of animal origin. The results demonstrate the existence of differences in congener-specific patterns between the analyzed samples. Variability was first demonstrated in terms of the food type (fish, meat, milk, fatty products). Then a variability was observed that was related to the specific animal species for meat and milk samples (bovine, ovine, porcine, caprine and poultry). Some practical applications of these results are discussed. The origin(s) of the observed differences, as well as their significance, now remain to be investigated, both in terms of environmental factors and transfer through living organisms. A better knowledge of the relation between a contamination profile and its specific source and/or food product should be of great interest to scientists working in the fields of contaminant analysis, toxicology and metabolism, as well as to regulatory bodies and risk assessors in charge of final decisions regarding the eventual hazards associated with theses substances.     

废弃物燃烧产生的可吸入颗粒物中金属元素的排放特性研究

将纸屑、甘蔗渣、木粉、谷壳、垃圾衍生燃料（RDF）五种废弃物进行燃烧,采集其烟气中可吸入颗粒物（PM10）样品并分析,获得了颗粒物中金属元素的质量分数和排放特性,并与其相应的原料和灰烬中的金属元素质量分数比较。结果显示,废弃物燃烧的颗粒物中金属元素的种类与燃烧的物料有关;纸屑的颗粒物中金属元素的质量分数最低,RDF的最高,其余三种生物质废弃物的质量分数较相近;在五种样品中,一些重金属的质量分数很高,比土壤中的质量分数高出很多倍;金属元素在灰烬和颗粒物中的分布情况与金属元素的性质密切相关,且在可吸入颗粒物上有明显的富集。     

Computer-assisted peak recognition for polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in environmental samples

A software has been developed for the peak recognition of 136 polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) after high resolution gas chromatography coupled with mass spectrometry (HRGC/HRMS). Based on the retention times of ¹³C labelled 2,3,7,8-substituted PCDD/F internal standards, the retention times of all PCDD and PCDF can be calibrated automatically and accurately. Therefore, it is very convenient to identify the peaks by comparing the retention of samples and the calibrated retention times of their chromatograms. Hence, this approach is very significant because it is impossible to obtain always a standard chromatogram and PCDD/F analysis are very expensive and time consuming. The calibration results can be transferred to Excel for calculation. The approach is a first step to store costly and environmentally relevant data for future application.     

Setting up a decision rule from estimated uncertainty: emission limit value for PCDD and PCDF incineration plants in Wallonia, Belgium

Complex analytical procedures are often required to prove the non-compliance with a specific legislation. In the case of a small overlap of the limit, integration of the method uncertainty in the decision-making process is essential. The decision rule proposed in Wallonia, Belgium, for the non-compliance of waste incineration plants with the EU limit value for PCDD and PCDF emissions is presented. The method uncertainty was estimated annually over 6 years from duplicate measurements using two top-down approaches. Depending on the congener, the standard uncertainty varies from 30 to 85%, with a good correlation between calculations. The analytical contribution was estimated using a bottom-up evaluation. The impact of the sampling step was deduced from the whole estimation and represents more than 80% of the total uncertainty budget. No optimisation is foreseen at this time because of practical field constraints. Based on the average fraction of each congener, the uncertainty associated with the measurement result has been established and shows a high stability over the years. Using this value, a guard band has been calculated and will be proposed to the regulatory body. Presented at the Measurement Uncertainty Symposium, Berlin, Germany, April 2008.     

Characterizing air particulate matter composition and sources in Lisbon,Portugal

The goal of this research is to determine trends and sources of airborne particulates in the centre of Lisbon, by using speciated particulate-matter data and back-trajectory analyses. Results showed that, in 2007, the annual PM_2.5 concentration exceeded the World Health Organization recommended levels. PM_2.5 diurnal variability and the ratio between weekdays’ and weekends’ concentrations indicated that traffic contributed highly to decreasing air quality. Air back-trajectory analysis showed that maritime air mass transport had a significant role on air quality in Lisbon, promoting the decrease of anthropogenic aerosol concentrations.