Polychlorinated dibenzofurans determining

In general, capillary gas chromatography provides enough resolution for most determinations in environmental analysis. Multidimensional gas chromatography has been applied to environmental analysis mainly to solve separation problems for complex groups of compounds. Important applications of GC-GC can therefore be found in the analysis of organic micropollutants, where compounds such as polychlorinated dibenzodioxins (PCDDs) (10), polychlorinated dibenzofurans (PCDFs) (10) and polychlorinated biphenyls (PCBs) (11-15), on account of their similar properties, present serious separation problems. MDGC has also been used to analyse other pollutants in environmental samples (10, 16, 17). 

Christman et al. [72] gave details of procedures for extraction, clean-up, and concentration of samples of soil prior to the determination of their content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by gas chromatography and by gas chromatography-mass spectrometry. Instrumental parameters are also included. Some typical results are tabulated. 

SFE has also replaced many regulated solvents in analytical chemistry applications in recent years, primarily because it provides a more reliable measure of the concentrations of environmental contaminants and can play an important role in pollution assessment, abatement, and control. Advantages have been shown for using SFE compared to the conventional Soxhlet extraction with toluene for determining the presence of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in ashes from a municipal incinerator (Dolezal et al., 1995). SFE allows the complete extraction of the analytes from the sample, whereas conventional extraction results in an incomplete, and hence, inferior extraction. 

For the quantitative determination of polychlorinated diben-zodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), sample treatment and conservation play crucial roles, too. Only some of the 75 PCDD isomers and 135 PCDF isomers are highly toxic. The collection and analysis of the hazardous compounds present at ultratrace levels in environmental samples must preferably be isomer-specific. The exposure routes for these compounds originate from combustion processes (18-19). 

Wakimoto, T., Kannan, N., Ono, M., Tatsukawa, R., Masuda, Y., 1988. Isomer-specific determination of polychlorinated dibenzofurans in Japanese and American Polychlorinated biphenyls. Chemosphere 17, 743-750. 

Barring, H., Bucheli, T.D., Broman, D., Gustafsson, O. (2002) Soot-water distribution coefficients for polychlorinated dibenzofurans and polybrominated diphenyl ethers determined with the soot cosolvency-column method. Chemosphere 49, 515-523. 

Cooke M, Hatchel JA, Czuczwa JM, et al. 1988. Analytical and sampling techniques for the determination of ultratrace quantities of polychlorinated dibenzofurans and dibenzodioxins. In Proceedings 1987 EPRI PCB Seminar, Kansas City, MO, October 6-9, 1987. Palo Alto, CA Electric Power Research Institute, 7-1 -7-8. 

Smith LM, Stalling DL, Johnson JL. 1984b. Determination of part-per-trillion levels of polychlorinated dibenzofurans and dioxins in environmental samples. Anal Chem 56 1830-1842. 

Ryan JJ, Lizotte R, Panopio LG, Lau B, Masuda Y (1989), Chemosphere 18 149-154. The effect of strong alkali on the determination of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins ... 

Hagenmaier H, Brunner H, Haag R, Kraft M (1986), Fresenius Z. Anal. Chem. 323 24-28.. .Selective determination of 2,3,7,8-tetrachlordibenzo-p-dioxin in the presence of a large excess of other polychlorinated dibenzodioxins and polychlorinated dibenzofurans"... 

Patterson DG Jr., Isaacs SG, Alexander LR, Turner WE, Hampton L, Bernert JT, Needham LL (1991), in IARC Scientific Publication No. 108.,Environmental Carcinogens Methods of Analysis and Exposure Measurement, Vol. 11 Polychlorinated Dioxins and Dibenzofurans . determination of specific polychlorinated dibenzo-p-dioxins and dibenzofurans in blood and adipose tissue by isotope-dilution high-resolution mass spectrometry", p. 299-342, Eds. Rappe C, Buser HR, Dodet B, O Neill IK, International Agency for Research on Cancer, Lyon... 

U.S. Environmental Protection Agency (EPA) (1990), in Test Methods for Evaluating Solid Waste". Method 8290 Determination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by HRGC/HRMS", Washington, D.C. 

WakimotoT, Kannan N.Tatsukawa R, Masuda Y (1988), Chemosphere 17 743-750. Isomerspe-cific determination of polychlorinated dibenzofurans in Japanese and American polychlorinated biphenyls"... 

Quantitative structure-retention relationships (QSSRs) have been established for polychlorinated dibenzofurans to assist their determination by gas chromatography (GC) <2002MI7, 2003ANC1049, 2005MI1683>. 

A further example for the analysis of trace levels of pollutants is the determination of polychlorinated diben-zodioxins and polychlorinated dibenzofurans in milk. The method includes gel permeation chromatography, alumina cleanup, and porous graphitized carbon chromatography, followed by analysis by gas chromatography-... 

Oehme, M., Mano, S., Brevik, E., and Knutzen, J. 1989. Determination of polychlorinated dibenzofuran (PCDF) and dibenzo-p-dioxin (PCDD) levels and isomer patterns in fish, Crustacea, mussel and sediment samples from a fjord region polluted by Mg-production. Fresenius Z. Anal. Chem., 335, 987-997. 

It is now known that endocrine disrupting chemicals are emitted from combustion sources. Interest has focused on the emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F), which are also known carcinogens. However, oxy-PAH, epoxides, and other oxygenated species are known EDCs. These can also be emitted from combustion sources, although they are not well characterized. They are semipolar compounds that are difficult to analyze. Thus, improved methods of analysis are needed in conjunction with biological testing to determine the nature and quantity of EDC emissions from combustion sources. 

Determination of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans from stationary sources... 

In addition to the thermogravimetry experiments, batch pyrolysis experiments continuously monitoring HCl formation were performed with PVC to determine the optimum temperature for HCl formation. Under conditions of maximum HCl formation, PVC was pyrolyzed with and without oxygen in a fluidized bed reactor and the formation of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) measured. Avoiding the formation of these highly toxic compounds would be a critical element in any waste stream processing scheme. 

HPLC has been used in the extraction and purification of pollutants in environmental and biological samples. Its manifold applications are due to the availability of a number of stationary phases, particularly reversed phase columns of various dimensions. HPLC instruments used for this purpose are similar to the analytical machine but with the use of a different column, which depends on the nature of the pollutants to be extracted and purified. Many of the reports available in the literature deal with the use of HPLC as an extraction and purification technique for environmental and biological samples. For determinations of polar pesticides, HPLC appears to be the most appropriate technique for purification purposes [134, 135]. Smith etal. [136] used low pressure HPLC for the extraction of polychlorinated dibenzofurans and dioxins. Furthermore, Blanch era/. [137] used low pressure HPLC for the purification and extraction of PCBs from shark liver. Similarly, Ramos etal. [138] used the Smith etal. [136] method for the extraction of PCBs in dolphin liver. Bethan etal. [139, 140] used a LiChrosorb 100-Si HPLC column for the extraction of bromocyclen collected from river water and of ck-HCH in marine water. However, HPLC cannot achieve a reputation as the universal and highly applicable extraction technique, due to its low range with regard to preparative chromatography. Therefore, further advancement of the technique is required, especially with regard to the development of preparative columns. 

The severe health effects observed in the Japanese Yusho incident of 1968 were attributed to the ingestion of polychlorinated biphenyls (PCBs). At that time, the forefront of analytical chemistry was represented by the determination of trace components at the parts per million (ppm) concentration level. It was not until about ten years later that analytical methodology was able to detect polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) at concentrations of 10 parts per billion (ppb) or less in the presence of PCBs. The significance of the determinations lies in the assessment of risk to human populations exposed to undegraded PCBs and to mixtures of chemically similar compounds of concern derived from uncontrolled reactions such as might occur when a PCB filled transformer undergoes eventful failure. 

Methods for Determining Polychlorinated Dibenzodioxins and Polychlorinated Dibenzofurans... 

Ontario Ministry of the Environment and Energy, Method for the Determination of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans in Fish. 1993, Ontario Ministry of the Environment and Energy, Etobicoke, Ontario. Canada. 

SW-846, is used to measure emissions of semivolatile principal organic constituents. Method 0010 is designed to determine destruction and removal efficiency (DRE) of POHCs from incineration systems. The method involves a modification of the EPA Method 5 sampling train and may be used to determine particulate emission rates from stationary sources. The method is applied to semivolatile compounds, including polychlorinated biphenyls (PCBs), chlorinated dibenzodioxins and dibenzofurans, polycyclic organic matter, and other semivolatile organic compounds. 

Fraser CA, Gardner GJ, Maxwell PS, Kubwabo C, Guevremont R, Siu KWM, and Berman SS (1995) Preparation and certification of a biological reference material (CARP-i) for polychlorinated dibenzo-p-dioxin and dibenzofuran congeners. Fresenius J Anal Chem 352 143-147. Gahr A, Huber N, and Niessner R (1998) Fluorimetric determination of bromate by ion-exchange separation and post-column derivatization. Mikrochrm Acta 129 281-290. 

Oehme, M., M. Schlabach, K. Hummert, B. Luckas, and E.S. Nordoy. 1995. Determinations of levels of polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls and pesticides in harp seals from the Greenland Sea. Sci. Total Environ. 162 75-91. 

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