PCDF analysis

Bergqvist, P.-A. Strandberg, B. R pe, C. 1998, Lipid removal using semipermeable membranes in PCDD and PCDF analysis of fat-rich environmental samples. Chemosphere 38 933—943. 

The appropriate method for PCDD/ PCDF analysis is the EPA Method 8290 of the Test Methods for Evaluating Solid Waste, SW-846 (EPA, 1996a). According to the NPDES permit, effluent and influent water samples will be analyzed for VOCs by EPA Method 624 (EPA, 1983). 

Foster MG, Huneault H, Cosby O, et al. 1990. Assessment of reference materials for application to PCDD/PCDF analysis. Chemosphere 20 1285-1290. 

Fraisse D, Paisse O, Hong N, Gonnord MF (1994), Fresenius J. Anal. Chem. 348 154-158. improvements in GC/MS strategies and methodologies for PCDD and PCDF analysis I. Evaluation of the non-polar DB-5ms column44... 

Table 4.48 Accurate mass MID set up for PCDD and PCDF analysis in MID lock-and-cali mode (width first lock 0.3 Da and voltage settling time delays 10 ms). -q... 

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). 

Stalling, D.L., R.J. Norstrom, L.M. Smith, and M. Simon. 1985a. Patterns of PCDD, PCDF, and PCB contamination in Great Lakes fish and birds and their characterization by principal components analysis. Chemosphere 14 627-643. 

For decades, many countries and intergovernmental organizations have taken measures to prevent the formation and release of PCDD/PCDFs, and have also banned or severely restricted the production, use, handling, transport and disposal of PCBs. As a consequence, release of these substances into the environment has decreased in many developed countries. Nevertheless, analysis of food and breast-milk show that they are still present, although in levels lower than those measured in the 1960s and 1970s. At present, the major source of PCB exposure in the general environment appears to be the redistribution of previously introduced PCBs. 

Several attempts have been made to set up immunochemical techniques for dioxin analysis (reviewed in [230,238,239]). Frequently the detectability and selectivity accomplished have not been considered appropriate for the direct analysis of environmental samples. We should notice that due to the poor solubility of PCDDs and PCDFs in water, the levels of these contaminants in aqueous samples is very low. For this reason analysts usually prefer the use of chromatographic and spectrometric methods that perform using organic solvents. However, the speed and high sample throughput that can be accomplished with the immunochemical methods have prompted several research groups and companies to establish immunochemical methods. 

GC-EI-MS permits the direct analysis of mixtures, e.g., to analyze synthetic byproducts an advantage that made GC-EI-MS benchtop instruments become widespread in modem synthetic laboratories. The GC-EI-MS combination is especially successful in monitoring environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzofuranes (PCDFs), or other volatile organic compounds (VOCs). 

For the determination of the intralaboratory repeatability of the DR CALUX bioassay for sediment samples, two sediment extracts were analyzed 10 times. Each analysis was performed in triplicate. As a prerequisite for a correct triplicate analysis, the percentage standard deviation in the triplicate determination should be below 15%. This is in accordance with the harmonized quality criteria for eell-based bioassay analyses of PCDDs/PCDFs in feed and food as formulated by Behnisch et al. (Behnisch et al, 2001 a) and as detailed in European Union directive 2002/69/ EC and direetive 2002/70/EC. The repeatability for the low-2,3,7,8-TCDD-content sediment... 

Besselink, H., Leonards, R, Felzel, E., Brouwer, B. (2002). Analysis of polychlorinated dibenzo-p-dioxins (PCDD), dibenzofiirans (PCDF) and biphenyls (PCB) in fish using DR CALUX and GC/ MS Acomparison. Organohalogen Compounds 58 412 15. 

Rappe et al. have reported on the analysis of two commercial chlorophenate formulations from Scandinavian sources using a 50. m OV-17 column (7). The tetrachlorophenol was known to contain approximately 5 2,U,6-tri-, 50 2,3,l, 6-tetra- and 10 pentachlorophenol as their sodium salt. The combined levels of PCDDs and PCDFs (tetra- to octa-) were 10 and l60 yg/g, respectively. Whereas on the earlier analyzed PCP samples 0 0 ] the... 

Studying occupational exposure to highly contaminated chlorophenols, the analysis of PCDDs and PCDFs in blood samples seems to be a better parameter to follow than the level of chlorophenol in the urine. 

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). 

Rappe (25) summarized all the literature with regard to the analysis of polychlorinated dioxins and furans and concluded that, with the standards now available, isomer-specific analyses can be performed for all toxic PCDD and PCDF isomers. However, some attention still has to be focused on characteristics of analytical and concentration techniques that can be promising for the future (26). 

Where analytical methods are available it is largely because of a crossfertilisation of effort from well-established areas of food contaminants work. For example, the steady development since the 1960s of methods of analysis for chlorinated pesticides led to the analysis of food for polychlorinated biphenyls (PCBs) since PCBs were readily detectable by general methods used to analyse food for organochlorine pesticides. The analysis of food for chlorinated dioxins and furans (PCDDs and PCDFs) at the very low levels at which they are found in food is a more recent development, and one that is an important precedent since it arose from interest in environmental contamination rather than because of cross-fertilisation of scientific methodology from an established area of food chemistry. Although dioxins were detectable some years ago at much less sensitivity in some pesticides, it was environmental interest that led to their study at very low levels in the food chain. 

Survey results need to be very carefully assessed before they can be accepted and this must take account of how the analytical methods were applied, as well as the representativeness of the samples of food of the general supply. Since analysis for PCDDs, PCDFs and PCBs in food is a particularly complex and hence expensive and time-consuming process, particular care needs to be taken that statistically sufficient samples are analysed in each survey. 

Given all these difficulties it is not surprising that only recently have major surveys of PCDDs and PCDFs in food become a viable prospect. This now extends to congener-specific surveys for PCBs, although it is not usual to quantify all congeners, principally those with TEFs and those selected by the International Committee for the Exploration of the Sea43 for analysis in fish. 

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