High dioxin analysis

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. 

A recent study in the Netherlands also investigated the potential correlation between in utero exposure to PCBs, PCDDs and PCDFs and neurological development in infants.147 This study utilized high-resolution analysis of PCBs, PCDDs and PCDFs so that dioxin or toxic equivalents (TEQs) in each sample could be estimated, where... 

Apart from GPC with Bio-Beads, there are other automated clean-up approaches. Although GPC has several advantages, Focant and co-workers claimed that for the high-fat-content samples (4 g lipids) required in dioxin analysis, GPC suffered from several practical limitations and therefore could not be performed 100% automatically (59). Consequently, new high-capacity disposable silica (HCDS) columns were developed for the Power-Prep system. The combination of PLE and Power-Prep clean-up allowed 10 dioxin samples to be analyzed in 48 hrs. 

Brenner, K. S., I. H. Dorn, and K. Herrmann. 1986. Dioxin analysis in stack emissions, slags and the wash water circuit during high-temperature incineration of chlorine-containing industrial wastes Part 2. Chemosphere 75(9-12) 1193-99. 

Spinnel et cd. further developed the modular PFE approach for dioxin analysis. A matrbc retainer module filled with sulfuric acid impregnated silica gel was introduced between the sample. In this case, salmon muscle was mixed with sodium sulfate and the carbon trap. This procedure provided extracts clean enough to be analysed by GC-HRMS (high-resolution mass spectrometry) analysis after solvent evaporation to an appropriate final volume. 

High and Low Mass Resolution In the Case of Dioxin Analysis... 

High mass resolution is therefore also required to verify positive screening results in dioxin analysis (see also section 4.29). A comparison of the two spectrometric methods of the lower and higher resolution SIM techniques is shown in Figure 2.192 for the mass traces in the detection of TCDF (tetrachlorodibenzofuran) traces. 

A The Analysis of Polychlorinated Dibenzo-/>-dioxins and Polychlorinated Dibenzofiirans by High Resolution GC/Low Resolution MS... 

The interlaboratory results obtained from the analysis of defined standard solutions, but also from the analysis of sediment extracts prepared either by the coordinator of the study or by the participants themselves, also provide a measure of the variation between laboratories. The results show that the interlaboratory reproducibility ranges from 6.5% for the defined dioxin sample to 27.9% for the sediment sample extracted by the participants themselves. As was mentioned before, the reproducibility for this last sample is relatively high and most presumably due to the introduction of extra handlings (extraction and cleanup) to the total procedure. In addition, the fact that not all the participants had prior experience with the extraction protocol to be used could have added to the increase in variability of the process. Furthermore, the dilution factor was not dictated. This also introduces a certain degree of variation. For the reproducibility of the DR CALUX bioassay itself and not caused by differences in operating extraction conditions, the maximum variation between laboratories was observed to be 18.0%. The results for the sediment extract samples can also be used to estimate the method variability for extracts, that is, based on samples of unknown composition. Again, given the intra-as well as the interlaboratory variations observed in this study, it appears justified to conclude that the standard deviation of the means provides a reasonable estimate of the method variability, based on the overall aver-... 

TO-9 High volume Polyurethane foam sampling with High Resolution GC/High Resolution MS (HRGC/HRMS) analysis Polychlorinated dibenzo-p-dioxin... 

High resolution mass spectrometers used in dioxin/furan analyses (EPA Method 8290 and EPA Method 1613) offer supreme sensitivity, down to parts per quadrillion concentration levels in purified samples. These are research grade instruments with a principle of operation that is based on the separation of ions in a magnetic field followed by ion optics detection. Dioxin/furan analysis is a unique application... 

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