1
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Molecular-Level Insight of CP52/NBR Damping Composites through a Combination of Molecular Dynamics Simulation and Experimental Method. Polymers (Basel) 2023; 15:polym15030604. [PMID: 36771905 PMCID: PMC9920840 DOI: 10.3390/polym15030604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 01/26/2023] Open
Abstract
To enhance the damping properties of nitrile butadiene rubber (NBR), the elastomer used was blended with chlorinated paraffin 52 (CP52) to prepare NBR/CP52 composites. The results showed that CP52 could significantly enhance the damping properties of NBR and shift the glass transition temperature (Tg) to lower temperatures. Molecular dynamics models of the CP52/NBR system were established, and the damping properties of the CP52-reinforced NBR were investigated using molecular dynamics (MD) simulations. Through the combination of MD simulations and the experimental results, the essential mechanism of the enhanced damping properties of the NBR was methodically expatiated and was ascribed to the Cl-CP-H····NC-NBR (type I) and CP-Cl····H-NBR-CN (type II) analogous hydrogen bonds formed between NBR and CP52. The higher the CP52 content, the higher the analogous hydrogen bond concentration, and the better the damping properties of the CP52/NBR composites. The experimental results were very consistent with the MD simulation results, meaning that the combination method can provide a new means to optimize the design of damping materials and broaden the application range of small polar molecules in the damping modification of polar rubber materials.
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2
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Valderhaug S, Liu H, Gorovoy A, Johansen JE, van Mourik L, de Boer J, Gautun OR. Nuclear magnetic resonance as a tool to determine chlorine percentage of chlorinated paraffin mixtures. CHEMOSPHERE 2022; 308:136312. [PMID: 36096309 DOI: 10.1016/j.chemosphere.2022.136312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 08/13/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
A new simple method for chlorine percentage calculations (method C), from proton nuclear magnetic resonance (1H NMR) spectroscopy, has been established and applied to an industrial chlorinated paraffin (CP) mixture and 13 single-chain CPs of known carbon chain lengths. Two modified methods (method A and B), originating from the work of Sprengel et al., have been utilized on the same single-chain mixtures. All samples were analysed by 1H NMR and two-dimensional heteronuclear quantum coherence (HSQC) for this purpose. All three methods worked well for medium chlorinated (45-55% Cl) single-chain mixtures of known carbon chain lengths. Method A yielded the best result for mixtures of lower chlorine content (<45% Cl), method C gave better estimations for higher chlorine contents (>55% Cl). Compared to Mohr's titration, method A showed a deviation of 0.7-7.8% (3.6% average), method B 4.1-11.3% (7.0% average) and method C 0.6-11.6% (5.2% average), for all 13 single-chain mixtures. The new method C is the only method that could be applied for determining the chlorine percentage of industrial mixtures of multiple, unknown chain lengths.
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Affiliation(s)
- Solveig Valderhaug
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, NO-7491, Trondheim, Norway; Chiron AS, Stiklestadveien 1, NO-7041, Trondheim, Norway
| | - Huiling Liu
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, NO-7491, Trondheim, Norway; Chiron AS, Stiklestadveien 1, NO-7041, Trondheim, Norway
| | - Alexey Gorovoy
- Chiron AS, Stiklestadveien 1, NO-7041, Trondheim, Norway
| | | | - Louise van Mourik
- Department of Environment and Health (E&H), Faculty of Sciences, Vrije Universiteit, De Boelelaan, 1108, 1081, HV Amsterdam, Netherlands
| | - Jacob de Boer
- Department of Environment and Health (E&H), Faculty of Sciences, Vrije Universiteit, De Boelelaan, 1108, 1081, HV Amsterdam, Netherlands
| | - Odd Reidar Gautun
- Department of Chemistry, Norwegian University of Science and Technology, Høgskoleringen 5, NO-7491, Trondheim, Norway.
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3
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Schweizer S, Schulz T, Vetter W. A fast gas chromatography coupled with electron capture negative ion mass spectrometry in selected ion monitoring mode screening method for short-chain and medium-chain chlorinated paraffins. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9382. [PMID: 36001505 DOI: 10.1002/rcm.9382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
RATIONALE Chlorinated paraffins (CPs) are a group of anthropogenic pollutants that consist of complex mixtures of polychlorinated n-alkanes of different chain lengths (~C10 to C30 ). Persistence, bioaccumulation, toxicity, and long-range transport of short-chain chlorinated paraffins (SCCPs, C10 - to C13 -CPs) have prompted their classification as persistent organic pollutants (POPs) by the Stockholm Convention in 2017. Due to the varying chain lengths and chlorination degrees, quantification of SCCPs and medium-chain chlorinated paraffins (MCCPs, C14 - to C17 ) using gas chromatography coupled with electron capture negative ion mass spectrometry in selected ion monitoring mode (GC/ECNI-MS-SIM) is not only challenging but also very time consuming. In particular, up to eight GC runs per sample are required for the comprehensive GC/ECNI-MS-SIM quantification of SCCPs and MCCPs. These efforts are high especially if the samples do not contain CPs above the limit of detection (LOD), subsequently. METHODS We developed a semi-quantitative and sensitive method for the examination of SCCPs and MCCPs in one GC run. This GC/ECNI-MS-SIM screening method was based on the recording of Cl- (m/z 35 and 37), Cl2 - (m/z 70 and 72), and HCl2 - (m/z 71 and 73) isotope ions and evaluation of the ratios between them. RESULTS Correctness of the results of the screening method was verified by analysis of edible oils with and without CPs, CP standards, as well as a technical CP mixture. Polychlorinated biphenyls (PCBs) and other polyhalogenated aromatic compounds, as well as brominated flame retardants, do not form all of the fragment ions analyzed by the screening method. CONCLUSIONS After the screening, only CP-positive samples may need to be measured in detail. Measurement time will already be gained in the case of ~10% samples without CPs.
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Affiliation(s)
- Sina Schweizer
- Department of Food Chemistry (170b), University of Hohenheim, Institute of Food Chemistry, Stuttgart, Germany
| | - Tobias Schulz
- Department of Food Chemistry (170b), University of Hohenheim, Institute of Food Chemistry, Stuttgart, Germany
| | - Walter Vetter
- Department of Food Chemistry (170b), University of Hohenheim, Institute of Food Chemistry, Stuttgart, Germany
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4
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Chlorinated paraffins in nut-nougat and chocolate spreads from the German market. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.109385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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5
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Knobloch MC, Sprengel J, Mathis F, Haag R, Kern S, Bleiner D, Vetter W, Heeb NV. Chemical synthesis and characterization of single-chain C 18-chloroparaffin materials with defined degrees of chlorination. CHEMOSPHERE 2022; 291:132938. [PMID: 34798110 DOI: 10.1016/j.chemosphere.2021.132938] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/10/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Technical chlorinated paraffins (CPs) are produced via radical chlorination of n-alkane feedstocks with different carbon chain-lengths (∼C10-C30). Short-chain CPs (SCCPs, C10-C13) are classified as persistent organic pollutants (POPs) under the Stockholm Convention. This regulation has induced a shift to use longer-chain CPs as substitutes. Consequently, medium-chain (MCCPs, C14-C17) and long-chain (LCCPs, C>17) CPs have become dominant homologues in recent environmental samples. However, no suitable LCCP-standard materials are available. Herein, we report on the chemical synthesis of single-chain C18-CP-materials, starting with a pure n-alkane and sulfuryl chloride (SO2Cl2). Fractionation of the crude product by normal-phase liquid-chromatography and pooling of suitable fractions yielded in four C18-CP-materials with different chlorination degrees (mCl,EA = 39-52%). In addition, polar side-products, tentatively identified as sulfite-, sulfate- and bis-sulfate-diesters, were separated from CPs. The new single-chain materials were characterized by LC-MS, 1H-NMR and EA. LC-MS provided Relative retention times for different C18-CP homologues and side-products. Mathematical deconvolution of full-scan mass spectra revealed the presence of chloroparaffins (57-93%) and chloroolefins (COs, 7-26%) in the four single-chain C18-CP-materials. Homologue distributions and chlorination degrees were deduced for CPs and COs. 1H-NMR revealed chemical shift ranges of mono-chlorinated (δ = 3.2-5.3 ppm) and non-chlorinated (δ = 1.0-3.2 ppm) hydrocarbon moieties. The synthesized C18-single-chain standard materials and respective spectroscopic data are useful to identify and quantify LCCPs in various materials and environmental samples. CP- and CO-distributions resemble the ones of existing SCCP and MCCP reference materials and technical mixtures. Furthermore, these materials now allow specific studies on the environmental fate and the transformation of long-chain chloroparaffins and chloroolefins.
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Affiliation(s)
- Marco C Knobloch
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
| | - Jannik Sprengel
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstrasse 28, 70599, Stuttgart, Germany
| | - Flurin Mathis
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Zürich University of Applied Sciences ZHAW, Einsiedlerstrasse 31, 8820, Wädenswil, Switzerland
| | - Regula Haag
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Susanne Kern
- Zürich University of Applied Sciences ZHAW, Einsiedlerstrasse 31, 8820, Wädenswil, Switzerland
| | - Davide Bleiner
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstrasse 28, 70599, Stuttgart, Germany
| | - Norbert V Heeb
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland
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6
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Fernandes AR, Vetter W, Dirks C, van Mourik L, Cariou R, Sprengel J, Heeb N, Lentjes A, Krätschmer K. Determination of chlorinated paraffins (CPs): Analytical conundrums and the pressing need for reliable and relevant standards. CHEMOSPHERE 2022; 286:131878. [PMID: 34416588 DOI: 10.1016/j.chemosphere.2021.131878] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
The determination of chlorinated paraffins (CPs) has posed an intractable challenge in analytical chemistry for over three decades. The combination of an as yet unspecifiable number (tens - hundreds of thousands) of individual congeners in mass produced commercial CP mixtures and the steric interactions between them, contrive to defy efforts to characterise their residual occurrences in environmental compartments, food and human tissues. However, recent advances in instrumentation (mass spectrometric detectors and nuclear magnetic resonance), combined with interlaboratory studies, have allowed a better insight into the nature of the conundrums. These include the variability of results, even between experienced laboratories when there is insufficient matching between analytical standards and occurrence profiles, the poor (or no) response of some instrumentation to some CP congener configurations (multiple terminal chlorines or < four chlorines) and the occurrence of chlorinated olefins in commercial mixtures. The findings illustrate some limitations in the existing set of commercially available standards. These include cross-contamination of some standards (complex CP mixtures), an insufficient number of single chain standards (existing ones do not fully reflect food/biota occurrences), lack of homologue group standards and unsuitability of some configurationally defined CP congeners/labelled standards (poor instrument response and a smaller likelihood of occurrence in commercial mixtures). They also indicate an underestimation in reported occurrences arising from those CPs that are unresponsive during measurement. A more extensive set of standards is suggested and while this might not be a panacea for accurate CP determination, it would reduce the layers of complexity inherent in the analysis.
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Affiliation(s)
- Alwyn R Fernandes
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Walter Vetter
- Institute of Food Chemistry, (170b), University of Hohenheim, Garbenstraße 28, 70599, Stuttgart, Germany
| | - Caroline Dirks
- Wageningen Food Safety Research, Akkermaalsbos 2, 6708 WB, Wageningen, the Netherlands
| | - Louise van Mourik
- Department of Environment and Health, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1087, 1081 HV, Amsterdam, the Netherlands
| | | | - Jannik Sprengel
- Institute of Food Chemistry, (170b), University of Hohenheim, Garbenstraße 28, 70599, Stuttgart, Germany
| | - Norbert Heeb
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Anouk Lentjes
- Department of Environment and Health, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1087, 1081 HV, Amsterdam, the Netherlands
| | - Kerstin Krätschmer
- European Union Reference Laboratory (EURL) for Halogenated POPs in Feed and Food, Bissierstraße 5, 79114, Freiburg, Germany
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7
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Sprengel J, Krätschmer K, Vetter W. A new synthesis approach for the generation of single chain CP mixtures composed of a few major compounds. CHEMOSPHERE 2022; 287:132372. [PMID: 34592207 DOI: 10.1016/j.chemosphere.2021.132372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Chlorinated paraffins (CPs) are complex mixtures, which consist of thousands of individual compounds with no dominant representative. Consequently, knowledge on structure and environmental relevance of individual CP congeners is poor. Similarly to the synthesis of individual CPs, the generation of less complex CP mixtures that can be thoroughly analyzed may be used to overcome some drawbacks of the highly complex technical CP mixtures. Here, we present a new synthesis approach to generate such simple CP mixtures by decarboxylation of polyunsaturated fatty acids followed by saturation of the double bonds by chlorination. Specifically, α-linolenic acid (18:3Δ9,12,15) was decarboxylated to heptadecatriene. The resulting raw product was chlorinated with SO2Cl2. Purification by column chromatography led to a main fraction consisting of four major peaks originating from hexachloroheptadecane (C17H30Cl6) isomers (∼80% of the total peak area) along with ∼20 low abundant by-products, according to gas chromatography with electron capture negative ion mass spectrometry. In the same way, decarboxylation and subsequent chlorination of other polyunsaturated fatty acids may lead to further simple CP mixtures with other chain lengths. Although these simple CP mixtures cannot fully reflect the various structural features present in technical mixtures they could be beneficial for transformation studies because changes in the CP pattern can easily be noted which is in contrast to technical CP mixtures. Such simple CP mixtures could also be used in toxicity tests which are difficult to perform with technical CP mixtures because of their high complexity.
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Affiliation(s)
- Jannik Sprengel
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, D-70599, Stuttgart, Germany
| | - Kerstin Krätschmer
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, D-70599, Stuttgart, Germany; European Union Reference Laboratory for halogenated POPs in Feed and Food (EURL POPs), Bissierstraße 5, D-79114, Freiburg, Germany
| | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, D-70599, Stuttgart, Germany.
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8
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Knobloch MC, Schinkel L, Kohler HPE, Mathis F, Kern S, Bleiner D, Heeb NV. Transformation of short-chain chlorinated paraffins and olefins with the bacterial dehalogenase LinB from Sphingobium Indicum - Kinetic models for the homologue-specific conversion of reactive and persistent material. CHEMOSPHERE 2021; 283:131199. [PMID: 34153917 DOI: 10.1016/j.chemosphere.2021.131199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/12/2021] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
Structure, reactivity and physico-chemical properties of polyhalogenated compounds determine their up-take, transport, bio-accumulation, transformation and toxicity and their environmental fate. In technical mixtures of chlorinated paraffins (CPs), these properties are distributed due to the presence of thousands of homologues. We hypothesized that roles of CP dehalogenation reactions, catalyzed by the haloalkane dehalogenase LinB, depend on structural properties of the substrates, e.g. chlorination degree and carbon-chain length. We exposed mixtures of chlorinated undecanes, dodecanes and tridecanes in-vitro to LinB from Sphingobium Indicum bacteria. These single-chain CP-materials also contain small amounts of chlorinated olefins (COs), which can be distinct by mathematical deconvolution of respective mass-spectra. With this procedure, we obtained homologue-specific transformation kinetics of substrates differing in saturation degree, chlorination degree and carbon chain-length. For all homologues, two-stage first-order kinetic models were established, which described the faster conversion of reactive material and the slower transformation of more persistent material. Half-lifes of 0.5-3.2 h and 56-162 h were determined for more reactive and more persistent CP-material. Proportions of persistent material increased steadily from 18 to 67% for lower (Cl6) to higher (Cl11) chlorinated paraffins and olefins. Conversion efficiencies decreased with increasing chlorination degree from 97 to 70%. Carbon-chain length had only minor effects on transformation rates. Hence, the conversion was faster and more efficient for lower-chlorinated material, and slower for higher-chlorinated and longer-chained CPs and COs. Current legislation has banned short-chain chlorinated paraffins (SCCPs) and forced a transition to longer-chain CPs. This may be counterproductive with regard to enzymatic transformation with LinB.
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Affiliation(s)
- Marco C Knobloch
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
| | - Lena Schinkel
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Swiss Federal Institute of Aquatic Research and Technology Eawag, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Hans-Peter E Kohler
- Swiss Federal Institute of Aquatic Research and Technology Eawag, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Flurin Mathis
- Zürich University of Applied Sciences ZHAW, Unterstrass 31, 8820, Wädenswil, Switzerland
| | - Susanne Kern
- Zürich University of Applied Sciences ZHAW, Unterstrass 31, 8820, Wädenswil, Switzerland
| | - Davide Bleiner
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland; Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Norbert V Heeb
- Laboratory for Advanced Analytical Technologies, Swiss Federal Institute for Materials Science and Technology Empa, Überlandstrasse 129, 8600, Dübendorf, Switzerland
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Endo S. Refinement and extension of COSMO-RS-trained fragment contribution models for predicting the partition properties of C 10-20 chlorinated paraffin congeners. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:831-843. [PMID: 34019049 DOI: 10.1039/d1em00123j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
COSMO-RS-trained fragment contribution models (FCMs) to predict the partition properties of chlorinated paraffin (CP) congeners were refined and extended. The improvement includes (i) the use of an improved conformer generation method for COSMO-RS, (ii) extension of training and validation sets for FCMs up to C20 congeners covering short-chain (SCCPs), medium-chain (MCCPs) and long-chain CPs (LCCPs), and (iii) more realistic simulation of industrial CP mixture compositions by using a stochastic algorithm. Extension of the training set markedly improved the accuracy of model predictions for MCCPs and LCCPs, as compared to the previous study. The predicted values of the log octanol/water partition coefficients (Kow) for CP mixtures agreed well with experimentally determined values from the literature. Using the established FCMs, this study provided a set of quantum chemically based predictions for 193 congener groups (C10-20 and Cl0-21) regarding Kow, air/water (Kaw), and octanol/air (Koa) partition coefficients, subcooled liquid vapor pressure (VP) and aqueous solubility (Sw) in a temperature range of 5-45 °C as well as the respective enthalpy and internal energy changes.
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Affiliation(s)
- Satoshi Endo
- Health and Environmental Risk Division, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan.
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10
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Sprengel J, Rixen S, Kappenstein O, Vetter W. Transport of chlorinated paraffins (CPs) from baking oven doors into the food. FOOD CHEMISTRY-X 2021; 10:100122. [PMID: 34189456 PMCID: PMC8220329 DOI: 10.1016/j.fochx.2021.100122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/28/2021] [Indexed: 11/19/2022]
Abstract
Chlorinated paraffins (CPs) have been repeatedly detected in the kitchen environment. Especially baking ovens were contaminated with high CP amounts on the insides of the doors. To investigate if CPs could be transferred into baked food, we spiked self-synthesized single chain C12-CP and C15-CP standards onto the inside door of an unused, CP-free baking oven. Experiments were performed under different conditions to assess possible CP transportation pathways. Coconut fat was used as food simulant, the exhaust air was monitored with cellulose filter paper and remaining CPs were collected via cotton wipes. In all experiments, both C12- and C15-CPs could be identified in both the food simulant and the cellulose samplers. Mean transfer rates into the food simulant amounted to 2.2% for C12-CPs and 5.8% for C15-CPs. Baking of food in CP-containing baking ovens may perceptibly increase the CP intake of consumers.
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Affiliation(s)
- Jannik Sprengel
- Institute of Food Chemistry, University of Hohenheim, Garbenstr. 28, D-70599 Stuttgart, Germany
| | - Stefanie Rixen
- Institute of Food Chemistry, University of Hohenheim, Garbenstr. 28, D-70599 Stuttgart, Germany
| | - Oliver Kappenstein
- German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, D-10589 Berlin, Germany
| | - Walter Vetter
- Institute of Food Chemistry, University of Hohenheim, Garbenstr. 28, D-70599 Stuttgart, Germany
- Corresponding author.
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11
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12
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van Mourik LM, Janssen E, Breeuwer R, Jonker W, Koekkoek J, Arrahman A, Kool J, Leonards PEG. Combining High-Resolution Gas Chromatographic Continuous Fraction Collection with Nuclear Magnetic Resonance Spectroscopy: Possibilities of Analyzing a Whole GC Chromatogram. Anal Chem 2021; 93:6158-6168. [PMID: 33832223 PMCID: PMC8153385 DOI: 10.1021/acs.analchem.1c00049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
This study presents, for the first time, the successful
application
of analyzing a whole gas chromatography (GC) chromatogram by nuclear
magnetic resonance (NMR) spectroscopy using a continuous repeatable
and stable (n = 280) high-resolution (HR) GC fractionation
platform with a 96-well plate. Typically with GC– or liquid
chromatography–mass spectrometry analysis, (isomer) standards
and/or additional NMR analysis are needed to confirm the identification
and/or structure of the analyte of interest. In the case of complex
substances (e.g., UVCBs), isomer standards are often unavailable and
NMR spectra too complex to achieve this. This proof of concept study
shows that a HR GC fractionation collection platform was successfully
applied to separate, purify, and enrich isomers in complex substances
from a whole GC chromatogram, which would facilitate NMR analysis.
As a model substance, a chlorinated paraffin (CP) mixture (>8,000
isomers) was chosen. NMR spectra were obtained from all 96 collected
fractions, which provides important information for unravelling their
full structure. As a proof of concept, a spectral interpretation of
a few NMR spectra was made to assign sub-structures. More research
is ongoing for the full characterization of CP isomers using multivariate
statistical analysis. For the first time, up to only a few CP isomers
per fraction were isolated from a highly complex mixture. These may
be further purified and certified as standards, which are urgently
needed, and can also be used for persistency, bioaccumulation, or
toxicity studies.
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Affiliation(s)
- Louise M van Mourik
- Department of Environment and Health (E&H), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Elwin Janssen
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Robin Breeuwer
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Willem Jonker
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Jacco Koekkoek
- Department of Environment and Health (E&H), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Arif Arrahman
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Jeroen Kool
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
| | - Pim E G Leonards
- Department of Environment and Health (E&H), Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HV Amsterdam, The Netherlands
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13
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Sprengel J, Vetter W. Chlorinated paraffins in hinges of kitchen appliances. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:250. [PMID: 33829339 PMCID: PMC8026443 DOI: 10.1007/s10661-021-09023-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/22/2021] [Indexed: 05/05/2023]
Abstract
Chlorinated paraffins (CPs) are anthropogenic pollutants of growing environmental concern. These highly complex mixtures of thousands of homologs and congeners are usually applied as additives in lubricants or as flame retardants and plasticizers in polymers and paints. Recent studies indicated the presence of high amounts of CPs in the kitchen environment whose sources could not be unequivocally identified. One option was the use of CPs as or in lubricants of hinges. To test this hypothesis, we performed wipe tests on lubricants on 29 hinges of different types of kitchen appliances (refrigerators, baking ovens, dishwashers, freezers, microwave oven, pasta machine, food processor, steam cooker) and analyzed them for short-chain CPs (SCCPs) and medium-chain CPs (MCCPs). CPs were detected in 21 samples (72%). Per wipe, SCCP concentrations ranged between 0.02 and 10 µg (median 0.23 µg), while MCCPs ranged from 0.09 to 750 µg (median 1.0 µg). Highest MCCP amounts (380 and 750 µg per wipe, respectively) were determined in new and unused appliances. A medium correlation between SCCP content and appliance age was observed, but no additional statistic correlation between SCCP/MCCP amount and appliance type or manufacturer could be observed. CPs released from hinges by volatilization, abrasion, and cleaning processes could enter the environment and come in contact with persons living in the corresponding households.
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Affiliation(s)
- Jannik Sprengel
- Institute of Food Chemistry (170B), University of Hohenheim, Garbenstr. 28, 70593, Stuttgart, Germany
| | - Walter Vetter
- Institute of Food Chemistry (170B), University of Hohenheim, Garbenstr. 28, 70593, Stuttgart, Germany.
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Krätschmer K, Schächtele A, Vetter W. Short- and medium-chain chlorinated paraffin exposure in South Germany: A total diet, meal and market basket study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 272:116019. [PMID: 33293103 DOI: 10.1016/j.envpol.2020.116019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 05/22/2023]
Abstract
Short- and medium-chain chlorinated paraffins (SCCPs, MCCPs) are high-production volume industrial chemicals that have been previously reported to occur in food, packaging material and the environment. This study presents an assessment of dietary exposure for consumers in Southern Germany based on three different sampling approaches: (i) a classical market basket study (n = 154), (ii) the analysis of ready-made meals from restaurants (n = 10), and (iii) a total diet approach (n = 21). In 35% of the samples, CPs were below the method limit of quantification. Highest amounts of SCCPs and MCCPs were found especially in extra virgin olive oils (EVOOs) and fish. Homologue patterns indicated the partial removal of CPs during the refining of (other) edible oils. Ready-made meals contained only low amounts of CPs equal to estimations based on market basket samples. Total diet samples from the same hospital were generally comparable with each other regardless of diet, although vegetarian meal plans with high amounts of cheese and other dairy products contained up to an order of magnitude more CPs than other diets. Taking all approaches into account, calculated daily exposures for adults ranged 35-420 ng/kg bw/day for ΣSCCPs and 22-840 ng/kg bw/day for ΣMCCPs, which is between one and two orders of magnitude higher than the current dietary intake of polychlorinated biphenyls (indicator PCBs) in Europe.
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Affiliation(s)
- Kerstin Krätschmer
- European Union Reference Laboratory (EURL) for Halogenated POPs in Feed and Food, Bissierstraße 5, 79114, Freiburg, Germany; University of Hohenheim, Institute of Food Chemistry (170b), Garbenstraße 28, 70599, Stuttgart, Germany.
| | - Alexander Schächtele
- European Union Reference Laboratory (EURL) for Halogenated POPs in Feed and Food, Bissierstraße 5, 79114, Freiburg, Germany
| | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstraße 28, 70599, Stuttgart, Germany
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In vitro human cell-based TTR-TRβ CALUX assay indicates thyroid hormone transport disruption of short-chain, medium-chain, and long-chain chlorinated paraffins. Arch Toxicol 2021; 95:1391-1396. [PMID: 33555371 PMCID: PMC8032603 DOI: 10.1007/s00204-021-02994-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/28/2021] [Indexed: 12/20/2022]
Abstract
Over the last decades, short-chain chlorinated paraffins (SCCPs), medium-chain chlorinated paraffins (MCCPs), and long-chain chlorinated paraffins (LCCPs) have become the most heavily produced monomeric organohalogen compound class of environmental concern. However, knowledge about their toxicology is still scarce, although SCCPs were shown to have effects on the thyroid hormone system. The lack of data in the case of MCCPs and LCCPs and the structural similarity with perfluoroalkyl substances (PFAS) prompted us to test CPs in the novel TTR-TR CALUX assay for their thyroid hormone transport disrupting potential. Four self-synthesized and additionally purified single chain length CP mixtures (C10-CPs, C11-CPs, C14-CPs and C16-CPs) and two each of industrial MCCP and LCCP products were tested in parallel with PFOA. All CP mixtures influenced the TTR binding of T4, giving activities of 1,300 to 17,000 µg/g PFOA equivalents and lowest observable effect concentrations (LOELs) of 0.95 to 0.029 mM/L incubate. Highest activities and lowest LOELs were observed for C16-CPs (48.3% Cl content, activity 17,000, LOEL 0.047 mM/L) and a LCCP mixture (71.7% Cl content; activity 10,000; LOEL 0.029 mM/L). A trend of higher activities and lower LOELs towards longer chains and higher chlorination degrees was implied, but could not be statistically confirmed. Irrespectively, the less well examined and current-use LCCPs showed the highest response in the TTR-TRβ CALUX assay.
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16
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Endo S, Hammer J. Predicting Partition Coefficients of Short-Chain Chlorinated Paraffin Congeners by COSMO-RS-Trained Fragment Contribution Models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15162-15169. [PMID: 33207873 DOI: 10.1021/acs.est.0c06506] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Chlorinated paraffins (CPs) are highly complex mixtures of polychlorinated n-alkanes with differing chain lengths and chlorination patterns. Knowledge on physicochemical properties of individual congeners is limited but needed to understand their environmental fate and potential risks. This work used a sophisticated but time-demanding quantum chemically based method COSMO-RS and a fast-running fragment contribution approach to enable prediction of partition coefficients for a large number of short-chain chlorinated paraffin (SCCP) congeners. Fragment contribution models (FCMs) were developed using molecular fragments with a length of up to C4 in CP molecules as explanatory variables and COSMO-RS-calculated partition coefficients as training data. The resulting FCMs could quickly provide COSMO-RS predictions for octanol-water (Kow), air-water (Kaw), and octanol-air (Koa) partition coefficients of SCCP congeners with an accuracy of 0.1-0.3 log units root-mean-squared errors. The FCM predictions for Kow agreed with experimental values for individual constitutional isomers within 1 log unit. The distribution of partition coefficients for each SCCP congener group was computed, which successfully reproduced experimental log Kow ranges of industrial CP mixtures. As an application of the developed FCMs, the predicted Kaw and Koa were plotted to evaluate the bioaccumulation potential of each SCCP congener group.
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Affiliation(s)
- Satoshi Endo
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan
| | - Jort Hammer
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies (NIES), Onogawa 16-2, 305-8506 Tsukuba, Ibaraki, Japan
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Mézière M, Krätschmer K, Pe Rkons I, Zacs D, Marchand P, Dervilly G, Le Bizec B, Schächtele A, Cariou R, Vetter W. Addressing Main Challenges Regarding Short- and Medium-Chain Chlorinated Paraffin Analysis Using GC/ECNI-MS and LC/ESI-MS Methods. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1885-1895. [PMID: 32872783 DOI: 10.1021/jasms.0c00155] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The risk assessment of chlorinated paraffins (CPs), chemicals of widespread industrial use, is struggling without standardized analytical methods to obtain reliable occurrence data. Indeed, scientists face analytical challenges that hinder the comparability of analytical methods, among them uncontrolled ionization efficiency and lack of quantification standards. In this study, our goal was to investigate potential issues faced when comparing data from different mass spectrometry platforms and quantification methods. First, the injection of the same set of single-chain length standards in three different instrumental mass spectrometry set-ups (liquid chromatography-electrospray-Orbitrap (LC/ESI-HRMS), liquid chromatography-electrospray-time-of-flight (LC/ESI-MS), and gas chromatography-electron capture negative ion-Orbitrap (GC/ECNI-HRMS)) revealed a shift of homologue response patterns even in-between LC/ESI-based set-ups, which was more pronounced for CPs of low chlorination degree. This finding emphasizes the need for a comprehensive description of instrument parameters when publishing occurrence data. Second, the quantification of a data set of samples with four quantification methods showed that quantification at the sum SCCP and MCCP levels presented good comparability, while quantification at the homologue level remained unsatisfactory. In light of those results, we suggest that (i) response pattern comparison should only be performed between similar instrumental set-ups, (ii) experimental chlorination degrees should be used when quantifying according to the %Cl (instead of those provided by the suppliers), and (iii) concentration results should be expressed as the sum of SCCPs and MCCPs primarily, with an indication on the match between samples and quantification standards (for example their chlorine content).
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Affiliation(s)
| | - Kerstin Krätschmer
- EURL for Halogenated POPs, c/o State Institute for Chemical and Veterinary Analysis of Food (CVUA) Freiburg, Bissierstraße 5, 79114 Freiburg, Germany
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstraße 28, 70599 Stuttgart, Germany
| | | | | | | | | | | | - Alexander Schächtele
- EURL for Halogenated POPs, c/o State Institute for Chemical and Veterinary Analysis of Food (CVUA) Freiburg, Bissierstraße 5, 79114 Freiburg, Germany
| | | | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry (170b), Garbenstraße 28, 70599 Stuttgart, Germany
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18
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Heeb NV, Iten S, Schinkel L, Knobloch M, Sprengel J, Lienemann P, Bleiner D, Vetter W. Characterization of synthetic single-chain CP standard materials - Removal of interfering side products. CHEMOSPHERE 2020; 255:126959. [PMID: 32388263 DOI: 10.1016/j.chemosphere.2020.126959] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
The photolytic chlorination of n-alkanes in presence of sulfuryl chloride (SO2Cl2) was explored to produce new standard materials. Five mixtures of chlorinated tetradecanes were synthesized with chlorination degrees (mCl,EA) varying from 43.7% to 59.4% (m/m) based on elemental analysis. Chlorine-enhanced negative chemical ionization mass spectrometry (CE-NCI-MS) forcing the formation of chloride-adduct ions [M+Cl]- was applied to characterize these materials which all contained tetra-to deca-chlorinated paraffins. Deconvolution of respective mass spectra revealed the presence of chlorinated olefins (COs). CO levels were highest in materials, which were exposed longest. All synthesized materials also contained two classes of polar impurities, tentatively assigned as sulfite- and sulfate-diesters with molecular formulas of C14H28-xO3SClx (x = 1-4) and C14H28-xO4SClx (x = 3-6), respectively. MS data were in accordance with the proposed structures but further work is needed to deduce their constitutions. These compounds are thermolabile and were not detected with GC-MS methods. We could remove these sulfur-containing impurities from the CPs with normal-phase liquid chromatography. In conclusion, single-chain CP materials were synthesized via chlorination of n-alkanes with sulfuryl chloride, but these materials contained reactive side products which should be removed to gain non-reactive and stable CP materials suitable as standards and for fate and toxicity studies.
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Affiliation(s)
- Norbert V Heeb
- Empa, Swiss Federal Laboratories for Materials Science and Technology,Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
| | - Silvan Iten
- Empa, Swiss Federal Laboratories for Materials Science and Technology,Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland; ZHAW, Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Reidbach, CH-8820, Wädenswil, Switzerland
| | - Lena Schinkel
- Empa, Swiss Federal Laboratories for Materials Science and Technology,Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Marco Knobloch
- Empa, Swiss Federal Laboratories for Materials Science and Technology,Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland; University of Zürich, Department of Chemistry, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Jannik Sprengel
- University of Hohenheim, Institute of Food Chemistry, Garbenstrasse 28, D-70599 Stuttgart, Germany
| | - Peter Lienemann
- ZHAW, Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Reidbach, CH-8820, Wädenswil, Switzerland
| | - Davide Bleiner
- Empa, Swiss Federal Laboratories for Materials Science and Technology,Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland; University of Zürich, Department of Chemistry, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Walter Vetter
- University of Hohenheim, Institute of Food Chemistry, Garbenstrasse 28, D-70599 Stuttgart, Germany
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Yuan B, Lysak DH, Soong R, Haddad A, Hisatsune A, Moser A, Golotvin S, Argyropoulos D, Simpson AJ, Muir DCG. Chlorines Are Not Evenly Substituted in Chlorinated Paraffins: A Predicted NMR Pattern Matching Framework for Isomeric Discrimination in Complex Contaminant Mixtures. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2020; 7:496-503. [PMID: 32685603 PMCID: PMC7365351 DOI: 10.1021/acs.estlett.0c00244] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/30/2020] [Accepted: 04/30/2020] [Indexed: 05/06/2023]
Abstract
Chlorinated paraffins (CPs) can be mixtures of nearly a half-million possible isomers. Despite the extensive use of CPs, their isomer composition and effects on the environment remain poorly understood. Here, we reveal the isomeric distributions of nine CP mixtures with single-chain lengths (C14/15) and varying degrees of chlorination. The molar distribution of C n H2n+2-m Cl m in each mixture was determined using high-resolution mass spectrometry (MS). Next, the mixtures were analyzed by applying both one-dimensional 1H, 13C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Due to substantially overlapping signals in the experimental NMR spectra, direct assignment of individual isomers was not possible. As such, a new NMR spectral matching approach that used massive NMR databases predicted by a neural network algorithm to provide the top 100 most likely structural matches was developed. The top 100 isomers appear to be an adequate representation of the overall mixture. Their modeled physicochemical and toxicity parameters agree with previous experimental results. Chlorines are not evenly distributed in any of the CP mixtures and show a general preference at the third carbon. The approach described here can play a key role in understanding of complex isomeric mixtures such as CPs that cannot be resolved by MS alone.
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Affiliation(s)
- Bo Yuan
- Department
of Environmental Science, Stockholm University, SE-10691 Stockholm, Sweden
| | - Daniel Henryk Lysak
- Environmental
NMR Centre, University of Toronto, Toronto, ON, Canada M1C 1A4
| | - Ronald Soong
- Environmental
NMR Centre, University of Toronto, Toronto, ON, Canada M1C 1A4
| | - Andrew Haddad
- Environmental
NMR Centre, University of Toronto, Toronto, ON, Canada M1C 1A4
| | - Arika Hisatsune
- Environmental
NMR Centre, University of Toronto, Toronto, ON, Canada M1C 1A4
| | - Arvin Moser
- ACD/Labs, 8 King Street East, Toronto, ON, Canada M5C 1B5
| | | | | | - Andre J. Simpson
- Environmental
NMR Centre, University of Toronto, Toronto, ON, Canada M1C 1A4
| | - Derek C. G. Muir
- Canada
Centre for Inland Waters, Environment and
Climate Change Canada, Burlington, ON, Canada L7S 1A1
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20
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NMR and GC/MS analysis of industrial chloroparaffin mixtures. Anal Bioanal Chem 2020; 412:4669-4679. [PMID: 32468281 PMCID: PMC7329780 DOI: 10.1007/s00216-020-02720-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/12/2020] [Accepted: 05/15/2020] [Indexed: 11/02/2022]
Abstract
Chlorinated paraffins (CPs) are high-volume chemicals used worldwide in various industries as plasticizers, lubricants, and flame retardants. CPs are produced by chlorination of alkane mixtures which leads to complex products of thousands of homologs and congeners. Classic mass spectrometric analyses of CPs allow determining carbon chain lengths and degrees of chlorination while information on the substitution patterns cannot be derived. Therefore, we performed different one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR) experiments, elemental analysis (EA), and gas chromatography coupled with electron capture negative ion mass spectrometry (GC/ECNI-MS) for the analysis of ten technical CP products with 42%, 52%, and 70% chlorine content from four producers. Slight differences in chlorine content but varying chain length compositions were observed for similarly labeled products from different manufacturers. Two-dimensional heteronuclear spectral quantum coherence (HSQC) measurements helped to evaluate ten structural elements in the products and confirmed the presence of geminal chlorine atoms in primary and secondary carbons in products with 70% chlorine. The variation of signal groups increased with increasing chlorine content of the products. Two-dimensional heteronuclear multiple bond coherence (HMBC) analysis of one sample and GC/ECNI-MS measurements indicated the presence of impurities (e.g., C9-CPs, iso-alkanes) in different technical CP products. These methods could in future allow for better distinction of CP mixtures, and an improved trace-back of environmental CPs to the source, based on specific structural features. Additionally, further structural characterization could help in the development of more accurate analysis processes. Graphical Abstract.
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