Chlorines Are Not Evenly Substituted in Chlorinated Paraffins: A Predicted NMR Pattern Matching Framework for Isomeric Discrimination in Complex Contaminant Mixtures
| Autor: | Daniel H. Lysak, Ronald Soong, Dimitris S. Argyropoulos, Arvin Moser, Derek C. G. Muir, Arika Hisatsune, Bo Yuan, André J. Simpson, Sergey Golotvin, Andrew Haddad |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Ecology
Health Toxicology and Mutagenesis 010401 analytical chemistry chemistry.chemical_element 010501 environmental sciences Mass spectrometry 01 natural sciences Pollution Article 0104 chemical sciences NMR spectra database chemistry Chlorinated paraffins 13. Climate action Computational chemistry Environmental Chemistry Spectral matching Pattern matching Spectroscopy Waste Management and Disposal Carbon 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Environmental Science & Technology Letters |
| ISSN: | 2328-8930 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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