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Many studies involving polychlorinated dibenzo-p-dioxins and dibenzofurans (Cl4-Cl8) are limited to the 17 2,3,7,8-substituted congeners, which are used for the computation of the toxic equivalent concentration (TEQ) and often are the basis for regulatory actions. The values determined for total homolog groups may also be reported in some cases, e.g., Total Tetra-Dioxins, and such results provide some additional information but do not reveal the subtle details that can be derived from the study of individual congeners. There are 136 possible structures for tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans, including the 17 2,3,7,8-substituted congeners. In this work, the valuable role that inclusion of the other 119 congeners plays in understanding emission deviations (upsets) compared to normal operating conditions for a secondary aluminum smelter facility is illustrated. An exponential correlation was observed between the concentrations of specific non-2,3,7,8-substituted tetrachlorinated congeners (e.g., 2,3,6,7/3,4,6,7-TCDFs vs. 1,3,6,8-TCDD and 1,3,7,9-TCDD) and the TEQ-based emissions at the outlet of a baghouse pollution control device. The correlation possibly points to the additional and occasionally essential role played by metal-catalyzed stereoselective chlorination reactions taking place during the melting-purification process, as well as (conceivably) inside the air pollution control device. This chlorination in turn highlights not only the importance of the chlorine addition step and the kinetics involved with regard to regulating emission levels but also the role of measuring all 136 PCDD/F congeners.

In late 1990s, USEPA/FDA made an important connection regarding the presence of elevated levels of dioxins (e.g., 1500 ng kg(-1) TEQ) in ball clays mined in Mississippi (USA) from a geological deposit dated to ~40 million years (Mississippi Embayment) that stretches over several states (northern part of Mississippi to Kentucky) and levels of dioxins in selected animal food sources. Following a recent beach nourishment program along the mid-Atlantic coast of the US, a number of dark gray, blue tinted nuggets of varying sizes were found on beach strands and near the shoreline. Using the presence of these balls of clay (shape, color, and knowledge regarding their use in pottery) on the beach, together with our direct experience analyzing ball clays for dioxins, we made a possible association between these clays and elevated dioxins. Concerns regarding the potential of nourishment programs to cause severe damage to our beaches drove us to test the dioxin content of nourishment exposed clays. A number of the nuggets, along with freshly dredged and deposited sand (collected the morning after nourishment) with the same coloration, and others (sun-bleached), collected approximately 2 weeks after the completion of the nourishment efforts, were analyzed for the presence of PCDD/Fs, PCBs, and selected semi-volatile chlorinated organics. The clay PCDD/F WHO2005-TEQs (dry weight; ND=DL; EMPC=EMPC) ranged from 0.41 to 5.78 ng kg(-1) with an average of 2.64 ng kg(-1), whereas the sand sample's TEQs ranged from 0.18 to 0.31 ng kg(-1) PCDD/F WHO-2005, with an average of 0.22 ng kg(-1). The average total tetra- through octachlorinated dibenzo-p-dioxin concentration was 2700 ng kg(-1) (with a maximum of 5800 ng kg(-1)) for the clays and 8.5 ng kg(-1) (with a maximum of 16.8 ng kg(-1)) for the sand samples. The congener 2,3,7,8-TCDD (TEF=1) was detected in half of the clay samples (0.11-0.77 ng kg(-1)). All of the clay and sand samples displayed an unambiguous and dominating 1,4,6,9-chlorination pattern across homolog groups. No other chlorinated aromatics were detected above background levels. The observations, along with the absence or an extremely low level of polychlorinated dibenzofurans, together with the mineralogical analysis, supports the conclusion that off-shore dredging activities are reaching reservoir sources containing dioxin-tainted, smectic/kaolinite clay minerals. Subsequent beach erosion provides additional environmental releases over time, as buried balls of clay from previous nourishment efforts become exposed.

Analytical methodology has been developed for the isomer specific analysis of fifteen 2,3,7,8-substituted polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans in decabromodiphenyloxide and tetrabromobisphenol-A. The procedures, developed by the Brominated Flame Retardant Industry Panel, Triangle Laboratories, Incorporated, and Battelle, have been shown to afford accurate and precise measurements of the analytes in these matrices. Analysis of multiple DBDPO and TBBPA samples, collected at random, show that none of the analytes are present in concentrations at or above specified limits of quantitation.

Stannylamines, ‐phosphines and ‐arsines are shown to be configurationally stable within the NMR time‐scale, even in the presence of a strong nucleophile. The configurational stability of triorganotin hydrides and the configurational unstability of triorganotin halide has been checked. Copyright © 1975 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim

A method for the determination of all polychlorinated dibenzo- p -dioxin (PCDDs) and polychlorinated dibenzofurans (PCDFs), and hexachlorobenzene (HCB) contained in production batches of pentachlorophenol (PCP) samples is presented. The method uses two sub-samples of the PCP sample to provide an effective dynamic range of 1:40,000,000. Following extraction of the samples and fractionation of the sample extracts, the extracts are analyzed by HRGC/HRMS, and the resulting data from both sub-samples are combined to generate the final data for each sample. Data from the analysis of 47 samples using this method are presented and show a ratio of concentrations of octachlorinated dibenzofuran (OCDF) to 2,3,7,8-tetrachlorinated dibenzofuran (TCDF) of approximately 4,000,000:1. The results show that four congeners dominate the ITEQ, which has an average value of 634 μg kg −1 (429 μg kg −1 WHO 2005 TEQ) in those samples.

We review and discuss ultratrace extraction as a high-volume technique for quantifying persistent organic pollutants in aqueous matrices, including its evolution, its acceptance by scientific and regulatory communities, influential factors, published validation efforts and analytical issues to bring to light existing assumptions concerning its effectiveness. We identify important methodological gaps, which may affect potential analytical outcomes, to orient future validation efforts or to pursue more effective alternatives. We also review the function and the purpose of quality-control features. Regarding analytical issues, we examine those related to sample definition (e.g., the distinction between high-volume sampling and extraction) and the major sources of bias associated with measurement technology – particularly sample-preparation and analysis steps in the laboratory. We discuss challenging old ways of viewing sampling and analysis as independent entities, emphasizing that a change in sample configuration (i.e. multi-component, multi-matrix and voluminous samples) must result in changes in the analytical protocol, if reliable data are desired. Current methods are not structured to facilitate the adaptation needed to ensure data are reliable, even if they are based on powerful isotope-dilution technology. We review the literature to identify deficiencies related to validation of the technique, to provide a basis for experiments that scientists can consider to test expressed concerns (confirm or refute) and to evaluate their effects on data quality (precision and accuracy). It is necessary to review the state of the science to ensure that we do not develop and validate a procedure whose design is at odds with its purpose.

Data quality is an essential element in the evaluation of an environmental laboratory. The use of high resolution gas chromatography coupled with high resolution mass spectrometry and isotopically labeled variants of target analytes is discussed as a means to recognize subtle factors affecting data quality as well as provide higher quality data than other analytical technologies.

Methylneophylphenyltin hydride (I), (methylneophylphenylstannyl) cyclopentadienyl molybdenum tricarbonyl(II) and dimethylphenylstannylmethyl-α-naphthyl-phenylgermanium (III) are configurationally stable within the NMR time scale, even in the presence of strong nucleophiles.

An intensive investigation was made of the organic components of a representative fly ash sample from a municipal incinerator. The sample was analyzed using U.S. EPA RCRA Method 8280 incorporating both low and high resolution mass spectrometric techniques. Brominated and bromochlorinated analogs of polycyclic aromatic hydrocarbons as well as bromochlorinated dibenzodioxins and dibenzofurans were detected in this municipal incinerator fly ash sample.

Optically active triorganotin hydrides have been synthesized by asymmetric reduction of the corresponding halides. These optically stable compounds undergo stereoselective conversions into other optically stable compounds such as tetraorganotin compounds (by reaction with diazomethane or with bifluorenylidene) or hexaorganoditin compounds (by reaction in the presence of palladium) or into optically unstable compounds such as methylneophylphenyltin chloride (by reaction with CCl4). The HD exchange between optically active methylneophylphenyltin hydride (deuteride) and triphenyltin deuteride (hydride) occurs with retention of configuration at the metal atom.

The N-demethylation of 15N-labeled N-nitrosodimethylamine (DMN) and N-nitroso-N-methylaniline (NMA) by isolated rat hepatic cells has been investigated. The values obtained in this system for molecular nitrogen formed during metabolism, compared with substrate consumed, were DMN 47%, NMA 23%, and N-nitroso-N-methylurea (NMU) 105%. The results for DMN are roughly halfway between those previously determined with rat liver S-9 fraction in vitro (33%) and in vivo (67%). For NMA, the hepatocyte data are closer to those obtained from S-9 in vitro (19%), rather than the in vivo (52%). No mixed nitrogen ( 15N14N ) or labeled nitrogen oxides were found.

Several classes of organotin compounds are configurationally stable within the NMR time-scale and are even optically stable for weeks. Optically active tetraorganotin compounds, triorganotin hydrides and an optically active (triorganogermyl)triorganotin compound have been synthesized. Two reactions transforming optically active triorganotin hydrides into optically active tetraorganotin compounds are described.

Mass and ion abundance calibration of gas chromatograph/mass spectrometer responses is essential for the production of good data. In 1975, ion abundance criteria based on the mass spectrum of decafluorotriphenylphosphine (DFTPP) were proposed to standardize quadrupole mass spectra against magnetic sector spectra. This paper reports an investigation of DFTPP ion chemistry with the determination of the effects of some gas chromatograph/mass spectrometer operating parameters on the mass spectrum of DFTPP. New ion abundance criteria are proposed and discussed in relation to the findings of this investigation.

The metabolism of the non-carcinogenic N-nitrosoproline (NPRO) was investigated in vitro using both S9 preparations and isolated hepatocytes from F344 rats. The studies were performed using 15N-labeled nitrosamine and the reaction mixtures were examined mass spectrometrically for the presence of 15N2 or other 15N-labeled gaseous products. In addition, the metabolism of NPRO was monitored by capillary gas chromatography. The results indicated no 15N2 production from either the hepatocyte or S9 preparations, as well as no detectable loss of substrate from the reaction mixtures. Mass spectrometric analysis failed to reveal any metabolites of NPRO. The results suggest that NPRO may be refractory to the normal nitrosamine activating enzymes, confirming its suitability for use in human epidemiological studies of endogenous nitrosation.

The ammonia chemical ionization (CI/[NH4+]) mass spectra of a series of diastereomeric methyl and benzyl ethers derived from 3-hydroxy steroids (unsaturated in position 5 and saturated) have been studied. The adduct ions [M+NH4]+ and [MH]+ and the substitution product ions [M+NH4ROH]+ (thereafter called [MsH]+) are characterized by an inversion in their relative stabilites in relation to their initial configuration. [M+NH4]α+ and [MH]α+ formed from the α-Δ5-steroid isomers are stabilized by the presence of a hydrogen bond which is not possible for the β-isomers. This stereochemical effect has also been observed in the mass analysed ion kinetic energy (MIKE) spectra of [M+NH4]+ and [MH]+. The MIKE spectra of [MsH]+ indicate that those issued from the β-isomers are more stable than the one originating from the α-isomers. This behavior is also observed in the first field free region (HV scan spectra) for [MH]+, [MsH]+ and [M+NH4]+ which are precursors of the ethylenic carbocations (base peak in the conventional CI/[NH4]+ spectra). Mechanisms, such as SN1 and SNi, have been ruled out for the formation of [MsH]+, but instead the data support an SN2 mechanism during the ion-molecule reaction between [M+NH4]+ and NH3.

Racemic methylneophylptrityltin (I) reacts with an excess of butyllithium to give dibutylmethylneophyltin (II) in high yield, whereas bifluorenyl-9-ylmethylneophenyltin is converted with an excess butyllithium into butylmethylneophylphenyltin (III) together with some (II). This shows that the phenyl is cleaved off as easily as the trityl group but less than the bifluororenylyl group. Methylphenyl(phenylethynyl)(2-phenylpropyl)tin and phenylethynyltrimethyltin react with LiAlH 4 ; the phenylethynyl—tin bond is cleaved but the formed phenylacetylene and organotin hydride react together to give the expected adduct. Bifluorenyl-9-ylmethylneophylphenyltin is converted with LiAlH 4 , into 1,2-dimethyl-1,2-dineophyl-1,2-diphenylditin.

A stereospecific and regioselective SN2 mechanism (Walden inversion) is observed during studies involving modified terpenoid epimeric diols in a high-pressure ion source using ammonia as a reagent gas.

Stereospecific decomposition reactions of isomeric (cis and trans) deprotonated molecules from azabicycloalkane derivatives as azetidinols generated under negative chemical ionization (NCI)/OH− have been examined using mass-analysed ion kinetic energy (MIKE) and collisional activation (CA)/MIKE spectra. These measurements together with the ones obtained on specifically labelled compounds enabled us to determine the origin of the stereochemical effects. The results indicate that the hydroxylic proton constitutes the preferential (≃90%) site for the deprotonation process. Subsequent fragmentations of the deprotonated species observed in the second field-free region of a reversed geometry instrument are affected by the stereochemistry of the hydroxylic group. The isomer with the hydroxyl group in the cis position relative to the hydrogen at the ring junction mainly loses H2O, while the trans isomer eliminates CH3˙, both processes occurring with high specificity. Labelling studies indicate that two major pathways exist for the elimination of H2O from the cis isomer and the loss of CH3˙ from the trans isomer. The course of the reaction is determined by the ability of the stereoisomers to transfer a proton during the first decomposition step. When the size of the lactam ring is increased from a five-membered ring to a six- or seven-membered ring, these stereochemical effects tend to become less pronounced.

A fly ash sample found to contain polychlorinated dioxins and dibenzofurans was analyzed for brominated analytes. Bromochloro-polynuclear aromatic hydrocarbons, dioxins and dibenzofurans, as well as bromo PAH were found in ppt to ppb concentrations. Analytical results were confirmed by high-resolution mass spectrometric accurate mass determinations and by tandem mass spectrometry.

The formation of the products of microsomal metabolism of the cyclic nitrosamine, nitrosohexamethyleneimine (NO-HEX) were studied. Information on the origins of the oxygen atoms in four major metabolites of NO-HEX was obtained by metabolizing this compound in an 18O2 atmosphere using microsomes and cytosol, beta- and gamma-Hydroxy-NO-HEX are formed as a result of the insertion of a hydroxyl group derived from molecular oxygen into NO-HEX. All of the oxygen atoms in epsilon-aminocaproate (EAC) were derived from water. Approximately half of the molecules of epsilon- hydroxycaproate ( EHC ) contain an 18O atom; thus, half of the alpha-hydroxy-NO-HEX formed incorporates a hydroxyl group derived from molecular oxygen with the remainder of the hydroxyls being from water. To account for the above data and the related metabolic origins of EAC and EHC ( Hecker and McClusky , Cancer Res., 42 (1982) 59; Hecker et al., Teratogen. Carcinogen. Mutagen (1982) in press), we have proposed a mechanism for the formation of these compounds from cyclic nitrosamines catalyzed by microsomal and cytosolic enzymes.

Largomycin FII, a protein antitumor antibiotic of molecular weight 29, 300 daltons, contains a chromophore that is separable under mild denaturing conditions. The chromophore complex was found to be considerably less stable than the holoprotein towards light and heat, suggesting a protective effeect of the protein on the chromophore. Separation of the chromophore into several components was achieved using high performance liquid chromatography, and the biological activity of the isolated components was determined. Data gathered from UV, IR, proton and carbon NMR, and fast atom bombardment mass spectrometry indicated that all the chromophore components belong to the pluramycin class of antitumor agents. Pluramycin A and deacetylpluramycin A were found to be the two major components.

The first example of an optically active hexaorganoditin has been synthesized by the stereoselective reaction of the corresponding triorganotin hydride in the presence of palladium.

The presence of the nucleoside antitumor antibiotic toyocamycin in the fermentation broth was determined by a combination of negative and positive ion fast atom bombardment (FAB) mass spectrometry, high resolution FAB mass spectrometry and mass-analysed ion kinetic energy spectrometry (MIKES). A reasonable limit of detection for toyocamycin in the whole broth was obtained by combining the specificity of mass spectrometry/mass spectrometry (also called tandem mass spectrometry) to FAB. The role played by the fermentation matrix upon the production and the observation of characteristic ions by FAB. using xenon atoms was examined. High-performance liquid chromatography (HPLC) and FAB mass spectrometry were used to monitor toyocamycin at all stages of strain development, fermentation and recovery.

An analytical protocol for the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and total TCDDs in soil, sediment, and aqueous samples using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was evaluated through replicate analyses of fortified and unspiked soil and aqueous samples. The results of these analyses demonstrated that the method is useful for the determination of 2,3,7,8-TCDD and total TCDDs at concentrations ranging from 10 to 200 pg/g (ppt) in soil samples and from 100 to 2000 pg/l (ppq) in aqueous samples. Absolute recoveries of the method internal standard, (13C12-2,3,7,8-TCDD, ranged from 24 to 88%. Lower levels of detection can be achieved through a slight modification of the method with respect to initial sample size and/or final extract volume. Instrumental parameters that affect data quality, specifically HRGC column performance, mass resolution and mass measurement accuracy are presented.

DNA containing bound radioactive 7,12-dimethylbenz[a]anthracene was isolated from mouse fetal cell cultures exposed to this carcinogen. The carcinogen-deoxyriboside adducts within the DNA were found to be sensitive to acid-catalyzed hydrolysis. Adducts derived from reaction of a syn-dihydrodiol epoxide with deoxyadenosine residues in DNA were the most sensitive to acid and were hydrolyzed to yield a 1,2,3,4-tetrahydrotetraol of 7,12-dimethylbenz[a]anthracene under mild conditions. The structure of this tetraol was established by synthesis and mass spectrometry. Although definitive structures cannot be assigned at present to the nucleic acid adducts of this potent carcinogen, the present findings confirm and extend earlier work assigning partial structures to the major adducts.

Publisher Summary The term dioxins refer to chlorinated dibenzo-p-dioxins (CDDs) and furans to chlorinated dibenzofurans (CDFs). CDD or CDFs are not created intentionally, but are produced inadvertently by a number of human activities including chemical manufacturing and incomplete combustion, as well as by natural processes such as forest fires and volcanoes. In this chapter, the physical and chemical properties of CDD or CDFs and the toxicity equivalent (TEQ) methods are reviewed. This chapter describes the historical development of analytical methods and presents some of the pitfalls of using historical data in chemical fingerprinting. It provides an overview of the natural and anthropogenic sources of CDD or CDFs then outlines the general approaches used in forensic studies illustrated with three case studies. Identification of CDD or CDF sources in environmental and biological media is challenging because of low concentrations and associated analytical uncertainties; the potential need to compare data from different laboratories and different methodologies; the presence of multiple sources that are difficult to distinguish, particularly at low concentrations; and the confounding effects of chemical and biological transformations, particularly for airborne sources.

(−)-t-Butylneophylphenyltin hydride reacts with diazomethane to give (−)-t-butylmethylneophylphenyltin, while (−)- or (+)-methylneophylphenyltin hydrides add to the double bond of bifluorenylidene to give (−)- or (+)-bifluorenylylmethylneophylphenyltin, respectively

On-line high performance liquid chromatography (HPLC)-negative ion chemical ionization (NCI) mass spectrometry has been used for the analysis of explosives mixtures. The liquid chromatography-mass spectrometry (LC/MS) interface used was a commercial direct liquid introduction interface allowing about 1% of the solvent/sample effluent into the ion source. The HPLC mobile phases were acetronitrile/water (50:50) and methanol/water (50:50), which served also as NCI reagent gases. Standard mixtures containing 2,4,6-trinitrotoluene (TNT), cyclonite (RDX), tetryl, and pentaerythritol tetranitrate (PETN), and a military explosive, tetrytol, have been analyzed by the LC/MS system. The minimum detectable amount of TNT was 100 ng injected on column, or approximately 1 ng to the ion source.

The first example of an optically active hexaorganoditin has been synthesized by the stereoselective reaction of the corresponding triorganotin hydride in the presence of palladium.

The methyldiazonium ion, generated from four different precursors, was found to undergo proton exchange with deuteriated phosphate buffer solutions.