NMR and GC/MS analysis of industrial chloroparaffin mixtures

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., C 9 -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.

Chlorinated paraffins in hinges of kitchen appliances

“…CP-52 formulations have been shown to contain highly varying amounts of SCCPs (Gao et al, 2012(Gao et al, , 2016Li et al, 2018;Sprengel & Vetter, 2020). Low shares of SCCPs (i.e., 4% and 8%, respectively) were previously detected in two CP-52 products, mainly consisting of MCCPs (Sprengel & Vetter, 2020). Arguably, the CP formulations in most appliances were CP-52 with low SCCP shares, and higher Cl degrees could indicate the partial release of more volatile CPs with low(er) Cl degree.…”

“…Apart from two samples with chlorine contents of < 51%, this range was close to the %Cl content determined for the 52% Cl MCCP mixture (54.3% Cl). CP-52 formulations have been shown to contain highly varying amounts of SCCPs (Gao et al, 2012(Gao et al, , 2016Li et al, 2018;Sprengel & Vetter, 2020). Low shares of SCCPs (i.e., 4% and 8%, respectively) were previously detected in two CP-52 products, mainly consisting of MCCPs (Sprengel & Vetter, 2020).…”

Short- and Medium-Chain Chlorinated Paraffins in Polyvinylchloride and Rubber Consumer Products and Toys Purchased on the Belgian Market

“…C 10 CPs form the lightest carbon-chain group analyzed in this study, while hexachlorinated isomers are among the lightest chlorine groups such that these congeners are the most likely to volatilize from manufacturing components. Analyses of SCCP formulations by GC-MS using electron capture negative ionization (ECNI) have shown varying congener group distribution patterns [36][37][38] although the differences in ionization efficiency between GC-ECNI and LC technologies are known to be dependent on carbon and chlorine numbers such that direct comparisons between analyses are not instructive [33,35,39,40].…”

In vitro human cell-based TTR-TRβ CALUX assay indicates thyroid hormone transport disruption of short-chain, medium-chain, and long-chain chlorinated paraffins

“…All eight CP samples showed activity in the TTR-TRβ-CALUX © (expressed as µg PFOA equivalent per g substance), indicating thyroid hormone transport disrupting potential ( Table 2). The four single chain length CP mixtures showed similar chlorine contents (48.3-50.1% Cl content, section Industrial CP products and single chain length CP mixtures) and therefore similar mean carbon formulas (Sprengel and Vetter 2020). However, the TTR-T4 displacement (TTR-T4 disp ) in the TTR-TRβ-CALUX © test increased in the order C 10 -< C 11 -< C 14 -< C 16 -CPs by more than one order of magnitude (from 1300 up to 17,000, Table 3).…”

“…Two consisted almost exclusively of MCCPs and the remaining two of LCCPs. Following their recent characterization by gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) and nuclear magnetic resonance spectroscopy (NMR) (Sprengel and Vetter 2020), these were labeled A-52 (MCCP-1), B-52 (MCCP-2), A-42 (LCCP-1) and A-70 (LCCP-2) with the initial letter indicating two producers (A and B) and the number representing the approximate degree of chlorination in weight% (namely 42%, 52% or 70%) (Sprengel and Vetter 2020). Four selfsynthesized single chain length CP mixtures were tested as well.…”