Automated HPLC Fractionation of PCDDs and PCDFs and Planar and Nonplanar PCBs on C18-Dispersed PX-21 Carbon

Uptake of radiolabeled 3,3',4,4'-tetrachlorobiphenyl into Japanese quail egg compartments and embryo following air cell and albumen injection

The avian embryo is an excellent model for testing adverse developmental effects of environmental chemicals as well as uptake and movement of xenobiotics within the egg compartments. Before incubation at embryonic day 0, ¹⁴ C 3,3',4,4'-tetrachlorobiphenyl (¹⁴ C PCB 77) was injected into Japanese quail eggs either onto the air cell or into the albumen. All egg components were collected on embryonic day 1, 5, or 10, and concentrations of ¹⁴ C PCB 77 were measured in various egg components (shell, membrane, yolk, albumen, and embryo). The results showed measurable ¹⁴ C PCB 77 in all egg components, with changing concentrations in each egg component over the course of embryonic development. Specifically, concentrations in the shell content decreased between embryonic days 1 and 10, increased in albumen from embryonic days 1 to 5 and then decreased at embryonic day 10, and increased in both yolk and embryo from embryonic days 1 to 10. Vehicle and injection site both influenced ¹⁴ C PCB 77 allantoic fluid concentrations, with little effect on other egg components except for the inner shell membrane. The fatty acid vehicle injected into the albumen yielded the highest ¹⁴ C PCB 77 recovery. These findings demonstrate dynamic movement of toxicants throughout the egg components during avian embryonic development and a steady increase of relatively low levels of ¹⁴ C PCB 77 in the embryo compared with the yolk, albumen, and shell, suggesting that embryonic uptake (i.e., exposure) mirrors utilization of egg components for nutrition and growth during development. Environ Toxicol Chem 2018;37:126-135. © 2017 SETAC.

Water-quality monitoring technique for dioxins during dredging using on-site solid phase extraction with graphitic carbon and analysis with DR-CALUX

In Japan, water-quality monitoring with the environmental dioxin standard of 1 pg-TEQ/L at basic monitoring points set in a border between operation-area water and normal water is necessary for removal operations for bottom sediments containing dioxins. This paper presents a technique for combining on-site graphitic carbon (GrC) solid-phase extraction and bioassay method for the simplification and facilitation of water-quality monitoring. Using this method, we conducted experiments at an actual sediment removal site. Comparative analyses using high-resolution GC/MS (HRGC-HRMS) between the dioxin concentrations detected using a GrC solid-phase extraction kit and the official analytical method yielded similar concentrations and distributions of isomers for detected PCDD/Fs and DL-PCBs. The GrC solid-phase extraction method is inferred to have capacity equal to official analytical method extraction. Toxicity equivalent concentrations estimated using DR-CALUX correlate with equivalent concentrations with HRGC/HRMS. No false positive or false negative result was obtained for the standard value 1 pg-TEQ/L.

Catalytic role of palladium and relative reactivity of substituted chlorines during adsorption and treatment of PCBs on reactive activated carbon

The adsorption-mediated dechlorination of polychlorinated biphenyls (PCBs) is a unique feature of reactive activated carbon (RAC). Here, we address the RAC system, containing a tunable amount of Fe as a primary electron donor coupled with Pd as an electrochemical catalyst to potentially respond to the characteristic of contaminated sites, effectively traps and treats various PCB congeners. A dramatic increase in RAC reactivity with Pd doping at as low as 0.01% suggests its critical role for accelerating hydrodechlorination of PCBs. Characteristic adsorption and dechlorination behavior and ensuing decomposition pathways of 13 selected PCB congeners are discussed with their surface interactions with RAC. Important findings include (i) inherent dechlorination susceptibility of chlorines in para > meta > ortho position, regardless of independent or competitive conditions as well as substrate effects, (ii) favorable reduction of more toxic coplanar PCB congeners, (iii) preferential electrophilic attack to chlorines in a less substituted phenyl ring and an isolated chlorine, regardless of the steric or inductive effect as a dominant limiting factor for the dechlorination of ortho or meta PCBs, respectively, (iv) prominent dechlorination inhibition for higher ortho congeners but negligible inhibition for higher meta congeners, and (v) eventual complete dechlorination of higher PCB congeners to biphenyl.

Four-Way Data Coupled to Parallel Factor Model Applied to Environmental Analysis: Determination of 2,3,7,8-Tetrachloro-dibenzo-para-dioxin in Highly Contaminated Waters by Solid−Liquid Extraction Laser-Excited Time-Resolved Shpol'skii Spectroscopy

This article reports the first application of parallel factor analysis to high-order instrumental data generated from Shpol'skii matrixes at liquid helium temperature. Third-order data arrays-consisting of excitation modulated wavelength time matrixes-are collected with the aid of a cryogenic fiber-optic probe, a tunable dye laser, and a multichannel system for phosphorescence detection. The multidimensional data formats are applied to the analysis of 2,3,7,8-tetrachloro-dibenzo-para-dioxin in water samples. The experimental procedure is rapid and environmentally friendly. Complete sample analysis is accomplished in less than 15 min with only 100 muL of organic solvent (n-heptane). The feasibility to directly determine parts-per-trillion concentration levels of the target compound is demonstrated with heavily contaminated samples of unknown composition. The limits of detection, estimated from calibrations based on the univariate method and parallel factor analysis, are 0.060 and 0.092 ng.mL(-1), respectively; both referred to a 100 mL water sample.

Accumulation of PCB congeners in nestling tree swallows (Tachycineta bicolor) on the Hudson River, New York

Tree swallows (Tachycineta bicolor) were used as a sentinel species to monitor the contamination and bioavailability of polychlorinated biphenyls (PCBs) in the Hudson River watershed. Several tree swallow nest box colonies around and downstream from Hudson Falls, NY, were studied. Tree swallow eggs, adults, and 5-, 10-, and 15-day-old nestlings were collected and analyzed for 103 PCB congeners. Emergent insects collected by net (primarily Odonata) or as a food bolus (primarily Diptera) taken from the mouths of adult tree swallows returning to the nest were analyzed in the same manner. Total PCB concentrations (wet weight) in eggs from two contaminated sites ranged from 9000 to 25,000 ng/g and accumulated to 32,000 and 96,000 ng/g in 15-day-old nestling at two contaminated sites. The congener patterns of PCBs in eggs, nestlings, and adults were compared to those found in emergent insects (Odonata and Diptera) using principal components analysis. The PCB patterns of the biota differed from that of Aroclor technical mixtures. PCB patterns in adult tree swallows were similar to those in eggs, while the patterns in dietary insects were similar to nestling tree swallows. Uptake rate constants were determined for tree swallow nestlings and compared between the two contaminated sites. The estimated PCB congener uptake rate constants were 0.008-0.02 d(-1) based on uptake in nestlings until day 15 post-hatch. The rate constants were comparable between the two study areas and may be used to predict nestling contamination at other locations. Our studies confirm the utility of nestling tree swallows to evaluate localized PCB contamination.

Soot sorption of non-ortho and ortho substituted PCBs

Field-observations of distribution coefficients well above expectations from bulk organic-matter partitioning for several chlorinated aromatic compound classes have lead to the hypothesis that enhanced affinity to soot may not be limited to polycyclic aromatic hydrocarbons but may extend as a significant process for a wider range of hydrophobic organic compounds. This suggestion was here tested in soot-column sorption experiments with a series of ortho- and non-ortho substituted polychlorinated biphenyls (PCBs), using diesel particulate matter (NIST standard reference material SRM-1650) as model soot sorbent. For congeners of similar hydrophobicity, considerably higher affinities toward the soot sorbent were observed for the non-ortho substituted PCBs. Mono- to tetra-ortho substituted PCBs exhibited log-based soot-water distribution coefficients (K(sc)) from 5.25 to 5.51 l/kg(sc) at solute concentrations corresponding to 1-13 microg/l. In contrast, biphenyl, mono- and dichloro- non-ortho substituted PCBs yielded logK(sc) values between 5.09 and 6.35 l/kg(sc). These results are 20-50, and 75-110 times higher, respectively, than the corresponding K(ow)-predicted K(oc) numbers. This strong interaction with soot, particularly of non-ortho substituted PCBs, may fundamentally affect their environmental distribution and bioavailable exposure.

Micropore-free surface-activated carbon for the analysis of polychlorinated dibenzo-p-dioxins-dibenzofurans and non-ortho-substituted polychlorinated biphenyls in environmental samples

2,3,7,8-Substituted polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and non-ortho-substituted polychlorinated biphenyls (PCBs) account for almost all of the total toxic equivalents (TEQ) in environmental samples. Activated carbon columns are used to fractionate the samples for GC-MS analysis or bioassay. Micropore-free surface-activated carbon is highly selective for PCDD/Fs and non-ortho-PCBs and can improve the conventional activated carbon column clean-up. Along with sulfuric acid-coated diatomaceous earth columns, micropore-free surface-activated carbon provides a rapid, robust, and high-throughput sample preparation method for PCDD/Fs and non-ortho-PCBs analysis.

Development of a high-performance liquid chromatography carbon column based method for the fractionation of dioxin-like polychlorinated biphenyls

A method to separate polychlorinated biphenyls (PCBs) by using high-performance liquid chromatography (HPLC) was developed. The HPLC column was packed with Amoco PX-21 activated carbon dispersed on octadecylsilane (ODS). The separation was carried out by gradient elution with n-hexane-dichloromethane and toluene in the forward direction followed by reversed elution with toluene. The results show that this HPLC method is useful for the separation of PCBs according to the number of substituted ortho chlorine atoms attached to the biphenyl structure. Average recoveries for a number of individual di-ortho PCBs, mono-ortho PCBs, and non-ortho PCBs in three selected elution windows were 97, 92, and 96%, respectively. Clophen A50, a herring sample, and a cod liver oil sample were fractionated on the column and the analytical results are compared with data from the literature. The method presented here is useful for quantitative separations of mono-ortho PCBs as well as non-ortho PCBs which have been assigned toxic equivalency factors by the World Health Organisation.

Graphitized carbons for solid-phase extraction

The objective of this review is to provide updated information about the most important features of graphitized carbonaceous sorbents used for solid-phase extraction (SPE) of organic compounds from liquid natural matrices or extracts. The surface characteristics of graphitized carbon blacks and porous graphitic carbons are described which are responsible for the various types interactions (hydrophobic, electronic and ion-exchange) with analytes. The method development is given which is based on the prediction from liquid chromatographic retention data obtained using porous graphitic carbon. Emphasis is placed on their capability for trapping very polar and water-soluble analytes from aqueous samples. Comparison is made between carbon-based SPE sorbents and other reversed-phase materials such as octadecyl silicas and highly cross-linked copolymers. Especially, the difficulty encountered for the desorption of some strongly retained analytes is explained by LC data and solutions are given for optimizing the composition and volume of the desorption solution. Many examples illustrate the various common features of graphitized carbons which are the extraction of very polar analytes and multiresidue extractions. Some applications are specific to graphitized carbon black due to the presence of surface functional groups. They include the extraction of anionic compounds such as benzene and naphthalene sulfonates or acidic pesticides. Other applications are specific to porous graphitic carbon due to its flat and homogeneous surface. One example is the trace extraction of coplanar polychlorinated biphenyls (PCBs), dibenzo-p-dioxins and dibenzofurans from other PCB congeners.

Selectivity of electron-donor- and electron-acceptor-bonded silica packing materials for hydrophobic environmental contaminants in polar and non-polar eluents

Electron-acceptor-bonded stationary phases, 2-(nitrophenyl)ethylsilyl (NPE) and 3-(p-nitrophenoxy)propylsilyl (NPO), and electron-donor-bonded phases, 3-(N-carbazolyl)propylsilyl (CZP), 2-(1-pyrenyl)ethylsilyl (PYE), and 5-coronenylpentylsilyl (COP), were prepared from silica particles and their selectivities were examined in both polar and non-polar solvents for specific isomers of polychlorodibenzo-p-dioxins (PCDDs), hexachloronaphthalenes (HxCNs) and planar and non-planar polychlorobiphenyl (PCB) congeners. Although no single stationary phase was able to separate all the isomer pairs that are coproduced during the synthesis of the PCDDs and HxCNs, pairs can be separated by selecting a suitable stationary phase and solvent. The separation of mixtures of PCDD isomers were found to be most successful with PYE and NPO phases, which yielded the opposite elution orders for each isomer pair that is produced as a mixture. Similar results were obtained for the HxCN isomers that were separated on PYE and CZP phases. The COP phase provided easier separation of non-ortho-substituted and mono-ortho-substituted PCBs from the other PCBs based on the planarity than PYE phase.

Validation of a congener specific method for ortho and non-ortho substituted polychlorinated biphenyls in fruit and vegetable samples

An on-line procedure has been developed and validated for the clean-up and fractionation of ortho and non-ortho-PCBs in fruit and vegetable samples. The procedure combines silica/acid and carbon/glass fibre columns with gas chromatography-mass spectrometry. Chromatography on carbon/glass fibre allowed collection of mono-ortho/di-ortho and non-ortho-PCB fractions, which were determined separately by GC-MS. The method was validated by replicate analyses and by inter-laboratory comparison of data for PCB congeners determined in fruit and vegetable samples collected in South Wales. The concurrent determination of ortho and non-ortho substituted PCBs is reported with recoveries ranging from 55-95% and a mean intra-laboratory precision (%COV) of 9.5% for apple extracts.

Gas chromatographic analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans are toxic compounds formed during natural processes and human activities. The extraction and clean-up for these compounds from various environmental and biological sources has been described. The gas chromatographic analysis of polychlorinated dibenzo dioxins/furans with different columns and detectors has been reviewed. The advantages of using a mass detector in the analysis are discussed.

Organochlorine contaminants in double-crested cormorants from Green Bay, WI: I. Large-scale extraction and isolation from eggs using semi-permeable membrane dialysis

A 41.3-kg sample of double-crested cormorant (Phalacrocorax auritus) egg contents was extracted, yielding over 2 L of egg lipid. The double-crested cormorant (DCC) egg extract, after clean-up and concentration, was intended for use in egg injection studies to determine the embryotoxicity of the organic contaminants found within the eggs. Large-scale dialysis was used as a preliminary treatment to separate the extracted contaminants from the co-extracted sample lipids. The lipid was dialyzed in 80x5 cm semi-permeable membrane devices (SPMDs) in 50-ml aliquants. After the removal of 87 g of cholesterol by freeze-fractionation, the remaining lipid carryover (56 g) was removed by 100 routine gel permeation chromatography (GPC) operations. A 41,293-g sample was thus extracted and purified to the extent that it could easily be placed at a volume of 5 ml, the volume calculated to be necessary for the egg injection study. Analyses were performed comparing contaminant concentrations in the final purified extract to those present in the original egg material, in the extract after dialysis and cholesterol removal, and in the excluded materials. Recoveries of organochlorine pesticides through dialysis and cholesterol ranged from 96% to 135%. Total polychlorinated biphenyls in the final extract were 96% of those measured in the original egg material. Analysis of excluded lipid and cholesterol indicated that 92% of the polychlorinated dibenzo-dioxins and -furans were separated into the final extract.