Isomer-specific Determination Research Articles

1H-NMR spectra of the 22 tetrachlorinated dibenzo-p-dioxins

The 22 tetrachlorinated dibenzo-p-dioxins (TCDDs) were prepared by reacting the dipotassium salt of a chlorinated catechol with a chlorinated benzene or an ortho-chlorinated nitrobenzene. Some of the purified reaction products contained isomers formed by the Smiles rearrangement. The 300 MHz 1H-Nuclear Magnetic Resonance (NMR) spectra of these reaction products are presented. The spectra were assigned by spectral analysis and by comparison of NMR integrations with data from Gas Chromatographic-Flame Ionization Detection (GC-FID) measurements. The uniqueness of the spectra makes NMR measurement an efficient means for the isomer-specific determination of the 22 TCDDs at the microgram level.

Isomer-specific determination of polychlorinated dibenzofurans in Japanese and American polychlorinated biphenyls

Extremely toxic Polychlorinated dibenzofurans (PCDFs) were identified in several Japanese and American commercial PCB preparations. These isomerspecific analyses revealed several toxic PCDFs including 2,3,7,8-tetra-, 1,2,4,7,8-penta-, 1,2,3,7,8-penta-, 2,3,4,7,8-penta- and 1,2,3,6,7,8 hexa-chlorodibenzofurans in commercial PCB preparations. The concentrations (μg/g) of PCDFs in unused Kanechlor 300, 400, 500, 600 were 7.5, 26, 7.2, 5.4 and in Aroclors 1242, 1248, 1254, 1260 were 0.60, 3.7, 4.2, 7.5 respectively. An attempt for the detection of polychlorinated dibenzo- p-dioxins (PCDDs) at <2 ng/g level revealed no detectable dioxins.

Isomer-specific determination of PCDD/PCDF in oil extracts from water leachates of a waste landfill

A clean-up procedure for the isomer-specific analysis of polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) in oil extracts from water leachates of a hazardous waste landfill is described. After pretreatment, the samples were chromatographed subsequently on Alumina B-Super I, silica gel/44% conc. H 2SO 4 and Bio-Beads S-X3. Separation of 2,3,7,8-tetra-CDD and final sample purification was performed on Alumina B-Super I (micro-column). Except for 2,3,7,8-tetra-CDF, all the 2,3,7,8-substituted PCDDs/PCDFs could be detected. Among the 2,3,7,8-tetra- to hexa-CDDs/CDFs, 2,3,7,8-TCDD was by far the most abundant isomer, determined at a mean concentration of 70.5 ppb. Industrial wastes from 2,4,5-trichlorophenol production are assumed to be the main source for the high concentration of 2,3,7,8-TCDD. From the isomer-specific analysis of the hepta-CDFs, pentachlorophenol can be considered as source of the higher chlorinated PCDDs/PCDFs.

Preparation and evaluation of OV‐240‐OH coated glass capillary columns for isomer specific determination of PCDDs and PCDFs

AbstractGlass capillaries were leached, dehydrated, persilylated with 1, 3‐bis (3‐cyanopropyl) tetramethyldisiloxane, and coated with OV‐240‐OH. After crosslinking and binding the phase to the glass surface the columns showed high separation efficiency, high temperature stability, and inertness comparable to persilylated apolar columns. Column performance is shown to be superior to liquid phase cyanopropyl columns such as SP 2330. The excellent separation capabilities together with the selectivity of the phase makes OV‐240‐OH coated columns a valuable tool for the determination of toxic isomers in complex mixtures of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs). The order of elution of individual TCDD isomers was found to be similar to that described for SP 2330 or Silar 10c. The detection of PCDDs and PCDFs in a fly ash extract further illustrates the utility of OV‐240‐OH coated columns. The high temperature limit of these columns opens the way for the analysis of high boiling compounds such as mixed brominated/chlorinated dibenzo‐p‐dioxins and dibenzofurans.

Isomer specific determination of polychlorinated dibenzo-p-dioxins and dibenzofurans in incinerator related samples in Japan

Isomer specific determination of polychlorinated dibenzo-p-dioxins and dibenzofurans in incinerator related samples in Japan

Isomer specific determination of polychlorinated biphenyls in animal tissues by gas chromatography mass spectrometry

A procedure was developed which determines the concentration and composition of PCB mixtures in animal tissues by using seven standard congeners to take in consideration the different sensitivities of isomers of different level of chlorination. The selection criterion of these congeners is the abundance in animal tissues. The PCB mixture present in the matrix is not compared with a commercial mixture, rather, the PCB congeners are analysed individually and summed up to give the real concentration. However, because congeners of very small abundances are neglected, some 10% of the PCB mixture is not evaluated. Therefore, a correlation with a high chlorinated commercial mixture (Aroclor 1254 and Clophen A 60) is necessary. The PCB concentrations measured in animal tissues are compared with those received according to a conventional procedure and the PCB composition found are discussed. Finally, an attempt will be made to define a simple measure for the degree of metabolization of a PCB mixture present in animals.

Analysis of waste from production of Na-pentachlorophenolate for polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF)

The production of Na-pentachlorophenolate (PCP-Na) from hexachlorobenzene yields waste, which was landfilled in Germany over a decade. For risk evaluation purposes an analysis of a waste sample from PCP-Na production for its major and minor components, especially 2,3,7,8-TCDD, was carried out. Due to the fact, that the major components of the waste sample analyzed, consisted of hexachlorobenze (HCB), octachlorodibenzodioxin (OCDD), decachlorobiphenyl, decachlorodiphenylether, and pentachlorophenol (PCP), the analysis for minor components like 2,3,7,8-TCDD and other 2,3,7,8-substituted PCDDs and PCDFs is rather difficult. A procedure for the determination of the major components by HPLC and a clean-up procedure for the isomerspecific determination of PCDDs and PCDFs in this sample by GC/MS is described.

Strategies and techniques for sample collection and analysis: experience from the Swedish PCB accidents.

A series of polychlorinated biphenyl (PCB) fires and explosion in PCB-filled capacitors and transformers is discussed. A sampling program followed by isomer specific determination of trace levels of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) is described. Data from a series of Swedish PCB accidents are given. In addition to PCDFs and PCDDs, we have also found a series of polychlorinated biphenylenes (PCBPs). Cleaning of contaminated areas was done by vacuum cleaning followed by high pressure washing.

Strategies and Techniques for Sample Collection and Analysis: Experience from the Swedish PCB Accidents

A series of polychlorinated biphenyl (PCB) fires and explosion in PCB-filled capacitors and transformers is discussed. A sampling program followed by isomer specific determination of trace levels of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) is described. Data from a series of Swedish PCB accidents are given. In addition to PCDFs and PCDDs, we have also found a series of polychlorinated biphenylenes (PCBPs). Cleaning of contaminated areas was done by vacuum cleaning followed by high pressure washing.

Isomer-specific determination of hexachlorodibenzo-p-dioxins by oxygen negative chemical ionization mass spectrometry, gas chromatography, and high-pressure liquid chromatography

All ten hexachlorodibenzo-p-dioxin (HCDD) isomers, prepared by micropyrolysis of chlorophenates, were studied by using mass spectrometry, gas chromatography, and high-pressure liquid chromatography. Of several ionization modes studied, oxygen negative chemical ionization was the most suitable for isomer identification. This technique enabling isomer specific identification to be carried out was applied to hexachlorodioxin impurities in pentachlorophenol samples and detected small amounts of 4:2 substituted isomer not previously known. 17 references, 7 figures, 2 tables.

Isomer specific determination of hexachlorodioxins in technical pentachlorophenol (PCP) and its sodium salt

A newly developed approach involving oxygen negative chemical ionization was employed to achieve isomer specific analysis of all ten hexachlorodioxins (HxCDD). A group of technical pentachlorophenols (PCP) and sodium salts of pentachlorophenol (NaPCP) originating from five different manufacturers were analyzed and the levels of different isomers of hexachlorodioxins determined. 1,2,3,6,7,8-HxCDD was the most abundant isomer in all the PCPs tested with levels ranging from 0.30 ppm to 21.3 ppm. The 1,2,3,7,8,9-HxCDD isomer was also found to be present in all the PCP samples but at lower levels of 0.01 ppm to 0.71 ppm. All ten isomers of HxCDD were observed in all samples of the sodium salts of PCP, however the 1,2,3,6,7,9-/1,2,3,6,8,9-HxCDD pair was the most abundant. The isomer distribution was found to be quite consistent in samples from the same manufacturer.

Isomer-selective determination of tetrachlorodibenzo-p-dioxins using hydroxyl negative ion chemical ionization mass spectrometry combined with high-resolution gas chromatography.

OH/sup -/ negative ion chemical ionization (NICI) mass spectrometry can be used for the isomer-specific determination of tetrachlorodibenzo-p-dioxins (TCDDs). When CH/sub 4//N/sub 2/O mixtures are used as a reagent gas, (M - H)/sup -/, M/sup -/, (M + OH)/sup -/, and (M - Cl)/sup -/ are formed in the ion source. When this technique is combined with high-resolution gas chromatography, 14 isomers including 2,3,7,8-TCDD can be identified by significant differences in the abundances of these ions. Monitoring of the (M + OH)/sup -/ adduct ion (formed by attack of the dioxin ring) allows an increase in the selectivity for TCDDs against polychlorinated biphenyls, pesticides, etc. A detection limit of 25 pg at m/z 337 (M + OH)/sup -/ (signal-to-noise 10:1) was obtained under standard conditions.

Laboratory data base for isomer-specific determination of polychlorinated biphenyls

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLaboratory data base for isomer-specific determination of polychlorinated biphenylsTed R. Schwartz, Randolph D. Campbell, David L. Stalling, Robert L. Little, Jimmie D. Petty, James W. Hogan, and Edwin M. KaiserCite this: Anal. Chem. 1984, 56, 8, 1303–1308Publication Date (Print):July 1, 1984Publication History Published online1 May 2002Published inissue 1 July 1984https://doi.org/10.1021/ac00272a025RIGHTS & PERMISSIONSArticle Views49Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (646 KB) Get e-Alerts Get e-Alerts

Isomer-specific determination of chlorinated dioxins for assessment of formation and potential environmental emission from wood combustion

The Dow Chemical Company has recently conducted a survey of residential wood combustion (RWC) units located in three different regions of the United States for chlorinated di-benzo-p-dioxin (CDD) emissions. The study was undertaken to determine if CDDs are produced during the combustion of wood, a naturally occurring fuel. RWC chimney particulates were collected from rural areas where locally obtained fuel would be expected to have minimal exposure to pesticides and herbicides. The development and application of appropriate analytical methodology has provided preliminary evidence that part-per-billion levels of CDDs are produced under these circumstances. 1 figure, 7 tables.

Determination of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans in Various Materials

Determination of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans in Various Materials