Detection of Bromochloro Alkanes in Indoor Dust Using a Novel CP-Seeker Data Integration Tool.

Bromochloro alkanes (BCAs) have been manufactured for use as flame retardants for decades, and preliminary environmental risk screening suggests they are likely to behave similarly to polychlorinated alkanes (PCAs), subclasses of which are restricted as Stockholm Convention Persistent Organic Pollutants (POPs). BCAs have rarely been studied in the environment, although some evidence suggests they may migrate from treated-consumer materials into indoor dust, resulting in human exposure via inadvertent ingestion. In this study, BCA-C14 mixture standards were synthesized and used to validate an analytical method. This method relies on chloride-enhanced liquid chromatography-electrospray ionization-Orbitrap-high resolution mass spectrometry (LC-ESI-Orbitrap-HRMS) and a novel CP-Seeker integration software package for homologue detection and integration. Dust sample preparation via ultrasonic extraction, acidified silica cleanup, and fractionation on neutral silica cartridges was found to be suitable for BCAs, with absolute recovery of individual homologues averaging 66 to 78% and coefficients of variation ≤10% in replicated spiking experiments (n = 3). In addition, a total of 59 indoor dust samples from six countries, including Australia (n = 10), Belgium (n = 10), Colombia (n = 10), Japan (n = 10), Thailand (n = 10), and the United States of America (n = 9), were analyzed for BCAs. BCAs were detected in seven samples from the U.S.A., with carbon chain lengths of C8, C10, C12, C14, C16, C18, C24 to C28, C30 and C31 observed overall, though not detected in samples from any other countries. Bromine numbers of detected homologues in the indoor dust samples ranged Br1-4 as well as Br7, while chlorine numbers ranged Cl2-11. BCA-C18 was the most frequently detected, observed in each of the U.S.A. samples, while the most prevalent degrees of halogenation were homologues of Br2 and Cl4-5. Broad estimations of BCA concentrations in the dust samples indicated that levels may approach those of other flame retardants in at least some instances. These findings suggest that development of quantification strategies and further investigation of environmental occurrence and health implications are needed.

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.

Thorough investigation of non-volatile substances extractible from inner coatings of metallic cans and their occurrence in the canned vegetables.

Since the decline of the use of bisphenol A, the chemistry of the varnishes and coatings which are applied to the inner surfaces of metallic food contact materials is poorly documented. We hypothesised that can coatings are now diverse and bring forth various non-intentionally added substances (NIAS) to be described. Investigating complex components such as NIAS requires demanding non-targeted approaches. We investigated the coatings of 12 vegetable cans from the French market. More than 125 substances were pinpointed, among them 84 oligoester combinations from 8 diols and 4 diacids. Thus, oligoesters were the dominant family. Additives such as epoxidised soybean oil, bisphenol A diglycidyl ether and benzoguanamine derivatives and phenol-formaldehyde oligomers were also identified. A software for exploring databases of theoretical combinations of polyester and phenol-formaldehyde resin components (NIAS-db 1.0) was made available. The stepwise organic synthesis of native and deuterated combinations of neopentyl glycol and isophthalic acid (4 and 8 units, linear and cyclic) enabled a higher confidence level and monitoring in vegetable extracts. Migration of oligoesters averaged 330 µg/kg in the drained vegetables (43-1600 µg/kg). This study sheds light on the need to fulfil a proper risk assessment on this NIAS family (exposure and hazard characterisation).

An annotation database for chemicals of emerging concern in exposome research.

BACKGROUND: Chemicals of Emerging Concern (CECs) include a very wide group of chemicals that are suspected to be responsible for adverse effects on health, but for which very limited information is available. Chromatographic techniques coupled with high-resolution mass spectrometry (HRMS) can be used for non-targeted screening and detection of CECs, by using comprehensive annotation databases. Establishing a database focused on the annotation of CECs in human samples will provide new insight into the distribution and extent of exposures to a wide range of CECs in humans. OBJECTIVES: This study describes an approach for the aggregation and curation of an annotation database (CECscreen) for the identification of CECs in human biological samples. METHODS: The approach consists of three main parts. First, CECs compound lists from various sources were aggregated and duplications and inorganic compounds were removed. Subsequently, the list was curated by standardization of structures to create "MS-ready" and "QSAR-ready" SMILES, as well as calculation of exact masses (monoisotopic and adducts) and molecular formulas. The second step included the simulation of Phase I metabolites. The third and final step included the calculation of QSAR predictions related to physicochemical properties, environmental fate, toxicity and Absorption, Distribution, Metabolism, Excretion (ADME) processes and the retrieval of information from the US EPA CompTox Chemicals Dashboard. RESULTS: All CECscreen database and property files are publicly available (DOI: https://doi.org/10.5281/zenodo.3956586). In total, 145,284 entries were aggregated from various CECs data sources. After elimination of duplicates and curation, the pipeline produced 70,397 unique "MS-ready" structures and 66,071 unique QSAR-ready structures, corresponding with 69,526 CAS numbers. Simulation of Phase I metabolites resulted in 306,279 unique metabolites. QSAR predictions could be performed for 64,684 of the QSAR-ready structures, whereas information was retrieved from the CompTox Chemicals Dashboard for 59,739 CAS numbers out of 69,526 inquiries. CECscreen is incorporated in the in silico fragmentation approach MetFrag. DISCUSSION: The CECscreen database can be used to prioritize annotation of CECs measured in non-targeted HRMS, facilitating the large-scale detection of CECs in human samples for exposome research. Large-scale detection of CECs can be further improved by integrating the present database with resources that contain CECs (metabolites) and meta-data measurements, further expansion towards in silico and experimental (e.g., MassBank) generation of MS/MS spectra, and development of bioinformatics approaches capable of using correlation patterns in the measured chemical features.

Non-targeted screening methodology to characterise human internal chemical exposure: Application to halogenated compounds in human milk.

Suspect and non-targeted screening approaches are a matter of increasing interest notably with regard to the Exposome contextual framework, but their application to human samples still remains limited at this date. The aim of the present study was to develop a non-targeted workflow from sample preparation to data processing and method assessment to characterise the human internal chemical exposure at early life stage. The method was focused on human milk to investigate mother and newborn exposure to known organic contaminants and to extend the characterisation to unknown compounds. We specifically focused on halogenated biomarkers of exposure due to persistence and potential toxicological impact reasons. The newly developed approach was based on a simple and fast sample preparation followed by a comprehensive analysis by both liquid and gas phase chromatography coupled to high resolution mass spectrometry. Critical steps of the non-targeted workflow as the method assessment have been addressed with a reference mix of 30 chlorinated and brominated contaminants encompassing various substances groups and a statistical approach. Data processing until the identification of biomarkers of exposure was possible with homemade bioinformatics tools. On the other hand, the method was validated by the identification of historical chemicals as hexachlorobenzene and p,p'-DDE and emerging chemical as 4-hydroxychlorothalonil. This approach opens the door to further extensions and consolidations to offer new capabilities for exposomics and environmental health research.

Transfer of short-, medium-, and long-chain chlorinated paraffins to eggs of laying hens after dietary exposure.

Chlorinated paraffins (CPs) are a complex family of contaminants. Lack of exposure data and an understanding of the fate of these chemicals in the environment affect our ability to reliably assess the human health risk associated with CP exposure. The present study focused on the evaluation of CP transfer from feed to eggs of laying hens exposed over 91 days. Laying hens were provided feed spiked with five technical mixtures of short-, medium- or long-chain CPs and featuring low or high chlorine contents, at concentrations of 200 ng/g each. Eggs were collected daily. All mixtures except the LCCPs with high chlorine content transferred into the eggs, with accumulation ratios increasing with the chain length and chlorine content. Concentrations at the steady-state varied between 41 and 1397 ng/g lw depending on the mixture. Additionally, the homologue-dependant transfer resulted in a change of pattern compared to that from the spiked feed.

Toward the characterisation of non-intentionally added substances migrating from polyester-polyurethane lacquers by comprehensive gas chromatography-mass spectrometry technologies.

Polyester-polyurethane lacquer, used to cover the inner surface of metallic food contact materials, may transfer non-intentionally added substances (NIAS) to the food. The identification of such a diversity of compounds, considered as migrating substances, requires taking advantage of complementary analytical platforms. Therefore, four types of gas chromatography-mass spectrometry (GCMS) couplings were investigated and compared for their abilities to identify migrating substances after acetonitrile extraction of two commercialised lacquers. In parallel, various ionisation sources, i.e. electron ionisation (EI) (70 eV and soft energies) and atmospheric-pressure chemical ionisation (APCI) as well as various mass analysers, i.e. quadrupole, time-of-flight (low and high resolution) and Orbitrap, were tested. Comparison of mass spectra with a commercial library for EI ionisation source led to the identification of two NIAS compounds, isophorone diisocyanate and 4,4'-diphenylmethane diisocyanate. Additionally, many cyclic oligoesters (four monomer units) were unambiguously identified according to supplier's declaration on starting materials used, primarily based on the molecular ion observed by APCI mode and characteristic fragment ions. High resolution mass analysers also enhanced confidence level in such NIAS identification. One- and two-dimensional GC were also investigated for separation assessment. Although GC × GC did not reveal additional NIAS, its use provided a valuable mapping of oligomers according to monomers composition. These results were compared to our previously published LC-MS study, carried out on the same lacquer samples. This study shows that LC and GC, along with their related ionisation techniques and their own selectivity, are complementary approaches, revealing different classes of compounds covering a wide range of volatility and polarity.

HaloSeeker 1.0: A User-Friendly Software to Highlight Halogenated Chemicals in Nontargeted High-Resolution Mass Spectrometry Data Sets.

In the present work, we address the issue of nontargeted screening of organohalogenated chemicals in complex matrixes. A global strategy aiming to seek halogenated signatures in full-scan high-resolution mass spectrometry (HRMS) fingerprints was developed. The resulting all-in-one user-friendly application, HaloSeeker 1.0, was developed to promote the accessibility of associated in-house bioinformatics tools to a large audience. The ergonomic web user interface avoids any interactions with the coding component while allowing interactions with the data, including peak detection (features), deconvolution, and comprehensive accompanying manual review for chemical formula assignment. HaloSeeker 1.0 was successfully applied to a marine sediment HRMS data set acquired on a liquid chromatography-heated electrospray ionization [LC-HESI(-)] Orbitrap instrument ( R = 140 000 at m/z 200). Among the 4532 detected features, 827 were paired and filtered in 165 polyhalogenated clusters. HaloSeeker was also compared to three similar tools and showed the best performances. HaloSeeker's ability to filter and investigate halogenated signals was demonstrated and illustrated by a potential homologue series with C12H xBr yCl zO2 as a putative general formula.