NMR and GC/MS analysis of industrial chloroparaffin mixtures

Structure Characterization and Products Control of Technical Chlorinated Paraffins by Direct Injection Mass Spectrometry With Data Deconvolution and 1H NMR With Chemometrics Tools

The diverse industrial use of chlorinated paraffins (CPs) have led to their environmental dispersion, and special attention has been paid to their ecotoxicology. Among them, short-chain chlorinated paraffins (SCCPs) have been listed as potential persistent organic pollutants (POPs). However, currently, technical CPs produced by manufacturers are usually labeled by their chlorination degree, but such structural label is not enough to reflect CPs' environmental fate and toxicity. Ecotoxicology research suggested that the chain length, chlorination degree and the chlorine distribution pattern are all factors that can determine CPs' environmental fate and toxicity. Herein, we present a cost-effective method for the structure characterization of technical CPs. By using direct injection mass spectrometry with data deconvolution, chain length distribution and homologous distribution in technical CPs mixture can be delineated. By using 1H NMR with chemometrics tools, the chlorine distribution pattern can be elaborated. Combining the abovementioned two analytical strategies, structural information at different levels that related to CPs' environmental fate and toxicities were revealed. This method is expected to be easily applied in both industry and academia, aiming for quality control of technical CPs, by permitting only nontoxic or noncarcinogenic CPs into industrial use.

Investigating polychlorinated alkanes in technical chlorinated paraffin mixtures and polymer products available in Vietnam

Chlorinated paraffins (CPs) are chemical additives mostly composed of polychlorinated alkanes (PCAs) which may impact on the environment and human health; however, little is known about their presence in Southeast Asia. To fill this knowledge gap, we assessed 74 PCA homolog groups commonly referred to as short-chain (SCCPs: PCAs-C10-13), medium-chain (MCCPs: PCAs-C14-17), and long-chain CPs (LCCPs: PCAs-C18-20) in technical CP mixtures (n = 4) and polymer samples (n = 49), including recycled plastics, collected in Vietnam in 2023. The contents of measured PCA homolog groups in technical CP mixtures were 86,000-930,000 mg/kg for PCAs-C10-13; 85,000-990,000 mg/kg for PCAs-C14-17; and 23,000-180,000 mg/kg for PCAs-C18-20. Total PCAs-C10-20 levels in polymer samples varied from 0.26 to 28,000 mg/kg and decreased in the order: soft plastic bag, electrical cable sheath, football pitch rubber, polyurethane hose, heat shrinkable tubing, spiral cable cover, plastic powder, and plastic drawstring. In polymer samples, PCAs-C14-17 were found at greater levels (mean/median: 3000/65 mg/kg) than PCAs-C18-20 (1300/9.5 mg/kg) and PCAs-C10-13 (740/16 mg/kg). The contents of total measured PCAs-C10-20 in polyvinyl chloride samples varied according to their life cycle stages, with higher levels found in recycled plastics than in feedstock and commercial product samples. The occurrence of PCAs-C10-13 in polymer samples above internationally proposed limits for PCAs-C10-13 in consumer goods and waste pose a conundrum for the implementation of a safe circular economy and may impact human health in Vietnam. Therefore, this study highlights key challenges for the through implementation of the Basel, Rotterdam, and Stockholm Conventions and the importance of further comprehensive investigations in Vietnam and other developing countries.

Parallel coupling of gas chromatography to mass spectrometry and solid deposition Fourier transform infrared spectroscopy: an innovative approach to address challenging identifications

The request for novel hyphenated instruments and techniques, capable of affording exhaustive information and results, is a focus continuously watched out. In this context, the present work aimed at the development of an integrated system combining gas chromatographic (GC) separation with mass spectrometry (MS) and (solid deposition) Fourier transform infrared spectroscopy (FTIR) detection. An external transfer line was designed in the lab for the parallel coupling of the two detectors, in such a way to obtain complementary analytical information consisting of an MS spectrum, an IR spectrum and linear retention indices (LRI), within a single analysis. The instrument performance was demonstrated for the analysis of a commercial mixture consisting of 139 hydrocarbons, comprising linear, branched, unsaturated and aromatic compounds. A 100-m poly(dimethylsiloxane) column was employed for the separation, and the outlet flow was split 95:5 between the IR and MS detectors using two uncoated capillaries. The IR spectra were acquired from solid deposits on a zinc selenide disc (-90 °C), over a spot (detector area) of about 0.1 mm2, in the range of 4000-700 cm-1 and at a resolution of 4 cm-1. Final identification of the separated compounds by a library search was achieved by excluding incorrect results, sequentially using a three-filter approach (85% similarity against reference MS and IR library spectra and ±10 LRI unit tolerance). Based on these preliminary results, the GC-MS/sd-FTIR system is a promising tool for the characterization of complex matrix constituents, for which identification is cumbersome, by using only one detection technique.

An international investigation of chlorinated paraffin concentrations and homologue distributions in indoor dust

In this study, very short-, short-, medium-, and long-chain chlorinated paraffins (vSCCPs, SCCPs, MCCPs and LCCPs, respectively) were measured in 40 indoor dust samples from four countries including Japan (n = 10), Australia (n = 10), Colombia (n = 10) and Thailand (n = 10). Homologues of the chemical formula CxH(2x+2-y)Cly ranging C6-36 and Cl3-30 were analysed using liquid chromatography coupled to Orbitrap high resolution mass spectrometry (LC-Orbitrap-HRMS) and integrated using novel custom-built CP-Seeker software. CPs were detected in all dust samples with MCCPs the dominant homologue group in all countries. Overall median ∑SCCP, ∑MCCP and ∑LCCP (C18-20) concentrations determined in dust samples were 30 μg/g (range; 4.0-290 μg/g), 65 μg/g (range; 6.9-540 μg/g) and 8.6 μg/g (range; <1.0-230 μg/g), respectively. Of the quantified CP classes, overall concentrations were generally highest in the samples from Thailand and Colombia, followed by Australia and Japan. vSCCPs with C≤9 were detected in dust from each country with an overall frequency of 48%, while LCCPs (C21-36) were present in 100% of samples. Estimated daily intakes (EDIs) calculated for SCCPs and MCCPs relating to ingestion of contaminated indoor dust were considered not to represent health risks based on currently available toxicological data using the margin of exposure (MOE) approach. To the authors' knowledge, this study provides the first data on CPs in indoor dust from Japan, Colombia and Thailand, and is among the first reports of vSCCPs in indoor dust, globally. These findings indicate that further toxicological data and the availability of appropriate analytical standards are needed to evaluate the potential for negative health outcomes deriving from exposure to vSCCPs and LCCPs.

Homologue Composition of Technical Chlorinated Paraffins Used in Several Countries over the Last 50 Years─SCCPs Are Still Out There

Chlorinated paraffins (CPs) are widely produced chemicals, with certain CP subgroups facing global restrictions due to their environmental dispersion, persistence, bioaccumulation, and toxicity. To evaluate the effectiveness of these international restrictions, we assessed the homologue group contribution and the mass fraction of short-chain CPs (SCCPs: C10-C13), medium-chain CPs (MCCPs: C14-C17), and long-chain CPs (LCCPs: ≥C18) in 36 technical CP mixtures used worldwide over the last 50 years. Using low-resolution mass spectrometry (LC-ESI-MS/MS), we quantified 74 CP homologue groups (C10Cl4-C20Cl10). Additionally, high-resolution mass spectrometry (LC-ESI-QTOF-MS) screening was employed to identify unresolved CP contents, covering 375 CP homologue groups (C6Cl4-C30Cl30). Overall, 1 sample was mainly composed of Collapse

Key Words

• chemical additive
• chlorinated n-alkane
• flame retardant
• persistent organic pollutant
• plasticizer
• polychlorinated alkane
• suspect screening analysis

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MESH Headings

• Paraffin
• Tandem Mass Spectrometry
• Chromatography, Liquid

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Grants Collapse

Affiliation(s)

Yago Guida Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, 21941-902 Rio de Janeiro, Brazil
Hidenori Matsukami Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan
Gabriel Oliveira de Carvalho Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, 21941-902 Rio de Janeiro, Brazil
Roland Weber POPs Environmental Consulting, 73527 Schwäbisch Gmünd, Germany
Walter Vetter Institute of Food Chemistry (170b), University of Hohenheim, DE-70593 Stuttgart, Germany
Natsuko Kajiwara Material Cycles Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan

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Concentrations and homologue patterns of SCCPs and MCCPs in the serum of the general population of adults in Hangzhou, China

Due to their ubiquitous presence in the environment and humans, chlorinated paraffins (CPs) are a major environmental and public health concern. CPs are known to persist, bioaccumulate and potentially threaten human health, but reports on their internal exposure in the adult general population are still scarce. In this study, serum samples collected from adults living in Hangzhou, China, were quantified for SCCPs and MCCPs using GC-NCI-MS methods. A total of 150 samples were collected and subjected to analysis. ∑SCCPs were detected in 98% of the samples with a median concentration of 721 ng/g lw. MCCPs were found in all serum samples with a median concentration of 2210 ng/g lw, indicating that MCCPs were the dominant homologous group. For SCCPs and MCCPs, ∑C₁₀ and ∑C₁₄ were found to be the dominant carbon chain length homologues. Our results showed that age, BMI and lifestyle were not found to be significantly associated with internal exposure to CPs for the samples in this study. Based on PCA analysis, an age-specific distribution of CP homologues was observed. This suggests that internal exposure to CPs in the general population is related to exposure scenarios and history. The results of this study may contribute to a better understanding of the internal exposure to CPs in the general population and may provide a direction for the investigation of the source of exposure to CPs in the environment and daily life.

Nuclear magnetic resonance as a tool to determine chlorine percentage of chlorinated paraffin mixtures

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.

Short- and medium-chain chlorinated paraffins in polyvinyl chloride consumer goods available in the Japanese market

Chlorinated paraffins (CPs), including short-chain CPs (SCCPs) and medium-chain CPs (MCCPs), are hazardous chemical additives widely applied as plasticizers and flame retardants in polymers, mainly in polyvinyl chloride (PVC). In 2017, SCCPs were listed under the Stockholm Convention on Persistent Organic Pollutants (POPs). MCCPs were proposed for listing as POPs in 2021. SCCPs are also restricted under the Basel Convention, with two tentative low POP content (LPC) limits (100 and 10,000 mg kg^-1) for SCCPs in waste. As a signatory Party of both conventions, Japan must ensure their implementation and manage SCCP wastes in environmentally sound ways. Therefore, we aimed to assess the occurrence of SCCPs and MCCPs in PVC consumer goods (n = 87) available in the Japanese market. CPs were detected in 48% of the samples. Regarding positive samples, children's products and toys (1.3-120,000 mg kg^-1) were more impacted by SCCPs whereas electrical and electronic cables (1.2-59,000 mg kg^-1) and house interior products (3.5-550 mg kg^-1) were more impacted by MCCPs. Fourteen and four samples exceeded the LPC limit of 100 and 10,000 mg kg^-1 for SCCPs, respectively. Most products were impacted by CP contents (<1 % w/w) considerably below those reported as intentional CP uses in PVC. However, 11 samples with total CP contents ranging from 1.3% to 15 % (w/w) might have been impacted by intentional CP use as secondary plasticizer in PVC. Most of the impacted consumer goods available in the Japanese market were manufactured overseas, highlighting that only restricting POPs nationally is not enough for thorough implementation of the Basel and Stockholm Conventions. Therefore, imported PVC consumer goods, PVC waste and PVC recycling streams need to be monitored as relevant potential sources of SCCPs worldwide, even where the national industry strictly follows the restriction of such chemicals.

A reference material (NMIJ RM 4076-a) for the determination of short-chain chlorinated paraffins

Chlorinated paraffins are primary industrial chemical products used for metalworking fluids and flame retardants. However, short-chain chlorinated paraffins (SCCPs) are registered in Annex A of the Stockholm Convention on Persistent Organic Pollutants. Therefore, since an accurate quantitative determination of SCCPs is crucial to monitor the level of pollution, analysis quality assurance with reference materials is needed. In this study, a reference material (RM), NMIJ RM 4076-a, was developed by the National Metrology Institute of Japan at the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) for the quantification of SCCPs. We determined the mass fraction of SCCPs by subtracting the impurities quantified using the mass-balance method, a combination of gas chromatography-flame ionization detection, Karl Fischer titrations, headspace-gas chromatography-mass spectrometry, and thermal gravimetric analysis. The mass fraction value of NMIJ RM 4076-a was concluded to be 0.9996 kg/kg. The standard uncertainty of this mass fraction was evaluated on the basis of the mass-balance method, the sample homogeneity, and stability obtained using the above analytical techniques. Accordingly, the expanded uncertainty estimated using a coverage factor of k = 2 was found to be 0.0013 kg/kg. The mass fraction of chlorine and the homologue compositional ratios are also given for this RM as supplementary technical information. This RM is expected to be applicable for use in the calibration of instruments, or for checking the validity of analytical methods or instruments for estimating the comparability of SCCP analyses.

Chemical synthesis and characterization of single-chain C18-chloroparaffin materials with defined degrees of chlorination

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 (m_Cl,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.

Chlorinated paraffins - A historical consideration including remarks on their complexity

Chlorinated paraffins (CPs) are high production volume chemicals currently produced and used in higher quantities than any other medium-size polyhalogenated compound (class). In addition, the composition of industrial CP mixtures is highly complex and poorly understood. In this article, we searched in the literature for the beginning of the chlorination of alkanes and how this substance class developed from niche applications to unmatched quantities in various industrial applications. Also, an estimation was made on the theoretical variety of chloroparaffins and the possible complexity of industrial CP mixtures. These data may explain why little is known about CPs although the production volume throughout the industrial generation was virtually always higher than the one of PCBs and has continued to increase after the ban of the latter.

Determination of chlorinated paraffins (CPs): Analytical conundrums and the pressing need for reliable and relevant standards

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.

A new synthesis approach for the generation of single chain CP mixtures composed of a few major compounds

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.

Short- and medium-chain chlorinated paraffins in human blood serum of Czech population

Short- and medium-chain chlorinated paraffins (SCCPs; MCCPs) are widespread environmental pollutants with bioaccumulation potential and adverse effects on human health. The analysis of blood serum is an important strategy to assess the human exposure to various contaminants, including SCCPs and MCCPs. Lately, the information about the exposure of Chinese population has been reported; nevertheless, data on human exposure to SCCPs and MCCPs outside East Asia are still very limited. In this pilot study, SCCPs and MCCPs were determined in 27 serum samples obtained from Czech adults. The samples were extracted by a three-step extraction (repeated with a clean solvent) by a mixture of n-hexane:diethyl ether (9:1, v/v) with subsequent clean-up on Florisil® solid phase extraction column. Gas chromatography coupled with high resolution mass spectrometry operated in negative chemical ionisation was employed for the instrumental analysis. The method recoveries ranged from 71 to 89% with repeatabilities of <20% (expressed as relative standard deviation). In the samples, SCCP concentrations were in the range of <150-2600 ng/g lipid weight, lw (median 370 ng/g lw) and the MCCP concentrations were in the range of <200-2110 ng/g lw (median 360 ng/g lw), respectively. To the best of our knowledge, our reported results are the first data about chlorinated paraffins in human blood serum in Europe, showing exposure to these compounds with yet to be studied effects on human health.

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

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.

Structural Identification and Quantification of Chlorinated Paraffins in Fish Samples Using Comprehensive Two-Dimensional Gas Chromatography with Negative Chemical Ionization Quadrupole Time-of-Flight Mass Spectrometry and Comparison to a Direct Injection-Atmospheric Pressure Chemical Ionization-Orbitrap/Mass Spectrometry Method

This study presents a comprehensive two-dimensional gas chromatography with negative chemical ionization quadrupole time-of-flight mass spectrometry (GC × GC-NCI-QTOF/MS) method, which allows for a precise chromatographic separation of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs). A new reversed-phase column setup was used, which allows for more accurate separation of MCCPs compared to known GC × GC methods. In a pilot study, 25 freshwater fish samples were analyzed with this method to characterize chlorinated paraffin (CP) compositions. The CP composition was similar in the samples, an observation that is important for the development of a suitable routine method. MCCP contamination was considerably higher than SCCP contamination, with concentrations of 1.3-410 ng/g of wet weight and 0.67-6.5 ng/g of wet weight, respectively. These results were compared to those obtained using a second method, direct injection-atmospheric pressure chemical ionization (APCI)-Orbitrap/mass spectrometry (MS). GC × GC separation was considered to be advantageous for accurate quantification of CP contamination.

Chlorinated paraffins in hinges of kitchen appliances

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.

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

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.

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

This study investigates the presence of Stockholm Convention listed short-chain chlorinated paraffins (SCCPs) and their replacement medium-chain chlorinated paraffins (MCCPs) counterparts in polyvinyl chloride and rubber consumer products and toys purchased on the Belgian market in 2019. SCCPs were detected in 27/28 samples at concentrations ranging from <LOQ-130,000 µg/g with a median level of 2.5 µg/g, while MCCPs were detected in only five samples ranging <LOQ-3500 µg/g. Levels of SCCPs in all but one of the samples were below the European Union's guideline limit of 0.15%, by weight, and concentrations of both SCCPs and MCCPs in the majority of products suggested unintentional incorporation to the polymeric materials. The homologue distribution of SCCPs was generally dissimilar to known commercial formulations and appeared to be indicative of contamination during manufacture or via recycling of previously treated goods. MCCP patterns, conversely, were broadly representative of those reported for industrial mixtures and may have been inadvertently incorporated via the application of mixed carbon-chain length CP formulations or recycled goods. This research suggests that overall SCCP presence has decreased in goods on the European market compared with previous reports and that both SCCPs and MCCPs may still enter EU marketplaces from unintentional sources.

A simplified screening method for short- and medium-chain chlorinated paraffins in food by gas chromatography-low resolution mass spectrometry

This study evaluates the performance of a simplified screening method for short- and medium-chain chlorinated paraffins (SCCPs and MCCPs, respectively) based on gas chromatography-electron capture negative ionization/mass spectrometry (GC-ECNI/MS) analysis and chlorine content quantification. The response from different combinations of 'indicator' congener groups present in technical mixture standards were used within calibration calculations to test the hypothesis that ∑SCCPs and ∑MCCPs could be quantified with acceptable accuracy using only a subset of the commonly analysed C₁₀ to C₁₇ and Cl₅ to Cl₁₀ groups. Potential combinations were assessed with respect to calibration curve performance and accuracy of SCCP and MCCP analysis of spiked food samples (olive oil, salmon, pork sausage, breakfast cereal, cow's milk and lard). Based on these trials, a screening method which quantifies ∑SCCPs and ∑MCCPs using only congener groups with 6 and 8 chlorine atoms for each carbon chain length was proposed. Concentrations of SCCPs and MCCPs in triplicate analyses of spiked food samples calculated using the proposed screening method deviated by ≤ 25% for the vast majority of samples (maximum deviation 37%) from levels determined using all analysed congener groups. The mean trueness of the screening method as applied to each of the spiked food samples and lard samples from a previous European Union Reference Laboratory (EURL) interlaboratory study ranged from 65 to 110% for ∑SCCPs and 102 to 175% for ∑MCCPs. Relative standard deviations (RSDs) were ≤ 25% for all triplicate analyses and matrix specific LOQs ranged from 0.7 to 6 ng/g ww for ∑SCCPs and from 1.3 to 12 ng/g ww for ∑MCCPs. The proposed screening method has the potential to deliver substantial time savings in instrumental analysis and manual labour without greatly reducing the overall accuracy and sensitivity of SCCP and MCCP quantification.