Anabolic steroids in livestock production: Background and implications for chemical food safety

The use of steroids in livestock animals is a source of concern for consumers because of the risks associated with the presence of their residues in foodstuffs of animal origin. Technological advances such as mass spectrometry have made it possible to play a fundamental role in controlling such practices, firstly for the discovery of marker metabolites but also for the monitoring of these compounds under the regulatory framework. Current control strategies rely on the monitoring of either the parent drug or its metabolites in various matrices of interest. As some of these steroids also have an endogenous status specific strategies have to be applied for control purposes. This review aims to provide a comprehensive and up-to-date knowledge of analytical strategies, whether targeted or non-targeted, and whether they focus on markers of exposure or effect in the specific context of chemical food safety regarding the use of anabolic steroids in livestock. The role of new approaches in data acquisition (e.g. ion mobility), processing and analysis, (e.g. molecular networking), is also discussed.

Innovative analytical methodologies for characterizing chemical exposure with a view to next-generation risk assessment

The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies. The use of less-conventional sampling strategies and integration of full-scan, high-resolution mass spectrometry and effect-directed analysis in environmental and human monitoring programmes have the potential to enhance the screening and identification of a wider range of chemicals of known, emerging or potential future concern. Here, we outline the key needs and recommendations identified within the European Partnership for Assessment of Risks from Chemicals (PARC) project for leveraging these innovative methodologies to support the development of next-generation chemical risk assessment.

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.

Polychlorinated Naphthalenes in Foods from the French Market: Occurrence, Dietary Exposure, and Evaluation of Relative Contributions to Dioxin-like Contaminants

Despite the growing interest in PCNs and the dioxin-like toxicity exhibited by a number of congeners, a comprehensive assessment of their contribution to the cocktail of dioxin-like contaminants is still lacking. To address such a shortcoming, this study investigated the PCN contamination in foodstuffs recently acquired in France, together with that of the regulatory polychlorinated dibenzodioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs). PCNs were ubiquitous at levels (∑70 PCNs = 2.5-150 pg g-1 wet weight) similar to those reported in other countries, with maximum concentrations observed in fish and fishery products from the North-East Atlantic Ocean. Their congener patterns further suggested unintentional releases of PCNs, while those of the other foodstuffs were correlated to the historical PCN profiles. Low risk from dietary exposure was estimated (∑70 PCNs-EDIs of 60-360 pg kg-1 bw d-1, ∑24 PCNs-TEQ-EDIs of 8 × 10-3-2.2 × 10-2 pg TEQ kg-1 bw d-1), with milk and dairy products being the highest contributors, followed by meat and meat products. Finally, the rather high contributions of PCNs to the total PCNs+PCDD/Fs+PCBs concentrations (0.9-50%, average of 9%) and the toxic equivalents (0.2-24%, average of 5%) show that these substances are not minor components of the PCNs+PCDD/Fs+PCBs cocktail.

Cocktails of endocrine disruptors in the different diets of French consumers

With a view to identifying main endocrine disruptors (ED) mixtures to which French consumers are exposed through food, their main diets were modelled using an adapted dimension reduction method. Seven specific diets could be modelled for adults while only one overall diet was considered for children aged 3-17 years. The knowledge of the contamination levels of 78 known or suspected endocrine disrupting compounds in the foods constituting these diets, collected in the frame of the second French Total Diet Study, made it possible to explore the mixtures of EDs to which consumers are exposed. We have thus shown that the ED substances most present in mass concentration are comparable for the whole population, whatever the diet considered. However, a second approach made it possible to highlight, for a given diet, the substances whose exposure is statistically higher than in the diet of the general population. Thus, significantly different ED mixtures could be established for each diet. For example, diets with a high proportion of animal-based foods induce significantly higher exposures to some persistent organic pollutants (e.g., PCDD/F, brominated flame retardants), whereas these exposures are lower for Mediterranean-type diet. On the other hand, the latter, richer in fruits and vegetables, is the one for which pesticides represent a specific signature.These results now pave the way for studying the specific effects of these cocktails of endocrine disruptors, each of which is representative of a type of chronic exposure linked to specific diets.

Non-targeted analysis of lipidic extracts by high-resolution mass spectrometry to characterise the chemical exposome: Comparison of four clean-up strategies applied to egg

Biota samples are used to monitor chemical stressors and their impact on the ecosystem and to describe dietary chemical exposure. These complex matrices require an extraction step followed by clean-up to avoid damaging sensitive analytical instruments based on chromatography coupled to mass spectrometry. While interest for non-targeted analysis (NTA) is increasing, there is no versatile or generic sample preparation for a wide range of contaminants suitable for a diversity of biotic matrices. Among the contaminants' variety, persistent contaminants are mostly hydrophobic (mid- to non-polar) and bio-magnify through the lipidic fraction. During their extraction, lipids are generally co-extracted, which may cause matrix effect during the analysis such as hindering the acquired signal. The aim of this study was to evaluate the efficacy of four clean-up methods to selectively remove lipids from extracts prior to NTA. We evaluated (i) gel permeation chromatography (GPC), (ii) Captiva EMR-lipid cartridge (EMR), (iii) sulphuric acid degradation (H2SO4) and (iv) polydimethyl siloxane (PDMS) for their efficiency to remove lipids from hen egg extracts. Gas and liquid chromatography coupled with high-resolution mass spectrometry fitted with either electron ionisation or electrospray ionisation sources operating in positive and negative modes were used to determine the performances of the clean-up methods. A set of 102 chemicals with a wide range of physico-chemical properties that covers the chemical space of mid- to non-polar contaminants, was used to assess and compare recoveries and matrix effects. Matrix effects, that could hinder the mass spectrometer signal, were lower for extracts cleaned-up with H2SO4 than for the ones cleaned-up with PDMS, EMR and GPC. The recoveries were satisfactory for both GPC and EMR while those determined for PDMS and H2SO4 were low due to poor partitioning and degradation/dissociation of the compounds, respectively. The choice of the clean-up methods, among those assessed, should be a compromise that takes into account the matrix under consideration, the levels and the physico-chemical properties of the contaminants.

Determination of bile acids in serum of pigs exposed to polychlorinated biphenyls by liquid chromatography-mass spectrometry

Exposure to polychlorinated biphenyls (PCBs) has been linked to dyslipidemia. Under acute exposure to PCBs, it has been observed that the secretion of bile acids (BAs) can be impacted, limiting (indirectly) lipid absorption in the gut. In this context, two non-targeted metabolomics studies on pig serum have recently suggested that BA concentrations may fluctuate under exposure to current non-dioxin-like (NDL)-PCB levels in food, reflecting the acute effects of such chronic exposure. The objective of this research is to implement a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for BA analysis in order to validate the findings of previous metabolomics studies, in which BA levels in serum samples from pigs exposed to environmental doses of NDL-PCBs were highlighted to be affected. The proposed LC-MS method involves the use of a C18-pentafluorophenyl LC column, which is not usually selected for the separation of BAs, but shows better performance for the separation of isomers than typical C18 columns. This LC-MS method shows excellent analytical performance such as low limits of detection (LODs) (≤1 ng/mL for most BAs) and good linearity (R2 > 0.994), while no matrix effect was observed. A total of 13 BAs have been quantified, while further BA isomers could be detected and semi-quantified. The application of this targeted LC-MS method confirmed previous findings, suggesting that exposure to low doses of NDL-PCBs decreases the concentration of BAs (i.e., glycochenodeoxycholic acid, hyodeoxycholic acid and taurochenodeoxycholic acid) while the effect on the precursors (cholic acid and chenodeoxycholic acid) is less pronounced.

Deeper insights into the effects of low dietary levels of polychlorinated biphenyls on pig metabolism using gas chromatography-high resolution mass spectrometry metabolomics

Polychlorinated biphenyls (PCBs) are a class of contaminants of great concern, linked to the development of many chronic diseases. Adverse effects of PCBs have been documented in humans after accidental and massive exposure. However, little is known about the effect of chronic exposure to low-dose PCB mixtures, and studies regarding scattered lifetime exposures to non-dioxin-like (NDL)-PCBs are especially missing. In this work, serum samples from pigs chronically exposed through their diet during 22 days to Aroclor 1260 (i.e. a commercially available mixture of NDL-PCBs) underwent a metabolomics analysis using gas chromatography-high resolution mass spectrometry (GC-HRMS), with the objective to investigate the effect of exposure to low doses of NDL-PCBs (few ng/kg body weight (b.w.) per day). The study showed that the serum profiles of 84 metabolites are significantly altered by the administration of Aroclor 1260, of which 40 could be identified at level 1. The aggregate interpretation of the results of this study, together with the outcome of a previous one involving LC-HRMS profiling, provided a substantial and concise overview of the effect of low dose exposure to NDL-PCBs, reflecting the hepatotoxic and neurotoxic effects already reported in literature at higher and longer exposures. These results are intended to contribute to the debate on the current toxicological reference values for these substances.

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.

A comparison of hydrophilic interaction liquid chromatography and capillary electrophoresis for the metabolomics analysis of human serum

Cationic, anionic, zwitterionic and, partially polar metabolites are very important constituents of blood serum. Several of these metabolites underpin the core metabolism of cells (e.g., Krebs cycle, urea cycle, proteins synthesis, etc.), while others might be considered ancillary but still important to grasp the status of any organism through blood serum analysis. Due to its wide chemical diversity, modern metabolomics analysis of serum is still struggling to provide a complete and comprehensive picture of the polar metabolome, due to the limitations of each specific analytical method. In this study, two metabolomics-based analytical methods using the most successful techniques for polar compounds separation in human serum samples, namely hydrophilic interaction liquid chromatography (HILIC) and capillary electrophoresis (CE), are evaluated, both coupled to a high-resolution time-of-flight mass spectrometer via electrospray ionization (ESI-Q-TOF-MS). The performance of the two methods have been compared using five terms of comparison, three of which are specific to metabolomics, such as (1) compounds' detectability (2) Pezzatti score (Pezzatti et al. 2018), (3) intra-day precision (repeatability), (4) ease of automatic analysis of the data (through a common deconvolution alignment and extrapolation software, MS-DIAL, and (5) time & cost analysis. From this study, HILIC-MS proved to be a better tool for polar metabolome analysis, while CE-MS helped identify some interesting variables that gave it interest in completing metabolome coverage in metabolomics studies. Finally, in this framework, MS-DIAL demonstrates for the first time its ability to process CE data for metabolomics, although it is not designed for it.

Collision cross-section as a universal molecular descriptor in the analysis of PFAS and use of ion mobility spectrum filtering for improved analytical sensitivities

The massive usage of per- and polyfluoroalkyl substances (PFAS), as well as their high chemical stability, have led to their ubiquitous presence in environmental matrices and direct human exposure through contaminated food, particularly fish. In the analysis of this large group of substances, the use of ion mobility coupled to mass spectrometry is of particular relevance because it uses an additional descriptor, the collision cross-section (CCS), which results in increased selectivity. In the present work, the ^TWCCS_N2 of 24 priority PFAS were experimentally obtained, and the reproducibility of these measurements was evaluated over seven weeks. The average values were employed to critically assess previously reported data and theoretical calculations. This gain in selectivity made it possible to increase the sensitivity of the detection on complex matrices (biota, food and human serum) by using the drift time associated to each analyte as a filter, thus reducing the interferences and background noise and allowing their detection at trace levels.

Performance assessment of an equine metabolomics model for screening a range of anabolic agents

INTRODUCTION

Despite their ban, Anabolic Androgenic Steroids (AAS) are considered as the most important threat for equine doping purposes. In the context of controlling such practices in horse racing, metabolomics has emerged as a promising alternative strategy to study the effect of a substance on metabolism and to discover new relevant biomarkers of effect. Based on the monitoring of 4 metabolomics derived candidate biomarkers in urine, a prediction model to screen for testosterone esters abuse was previously developed. The present work focuses on assessing the robustness of the associated method and define its scope of application.

MATERIALS AND METHODS

Several hundred urine samples were selected from 14 different horses of ethically approved administration studies involving various doping agents' (AAS, SARMS, β-agonists, SAID, NSAID) (328 urine samples). In addition, 553 urine samples from untreated horses of doping control population were included in the study. Samples were characterized with the previously described LC-HRMS/MS method, with the objective of assessing both its biological and analytical robustness.

RESULTS

The study concluded that the measurement of the 4 biomarkers involved in the model was fit for purpose. Further, the classification model confirmed its effectiveness in screening for testosterone esters use; and it demonstrated its ability to screen for the misuse of other anabolic agents, allowing the development of a global screening tool dedicated to this class of substances. Finally, the results were compared to a direct screening method targeting anabolic agents demonstrating complementary performances of traditional and omics approaches in the screening of anabolic agents in horses.

Health risk assessment to polychlorinated naphthalenes dioxin-like compounds in French sea food consumers

There has been a recent revival of interest in some historical contaminants such as polychlorinated naphthalenes (PCNs). However, occurrence data are still lacking in some countries although industrial production of PCNs has been reported. This observation led to the first ever assessment of their presence in fish and seafood products in France in the present work. Their analysis was integrated in an already validated method applied for polychlorinated dibenzodioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs), based on the structural similarity existing between these POPs. Performances of the method (LODs in the range 0.10-0.28 pg g^-1 wet weight (ww), LOQs in the range 0.33-0.93 pg g^-1 ww), enabled monitoring 69 di-to octachlorinated congeners in a large representative set of fish and seafood samples collected in 2005 in four coastal areas of the French mainland (n > 30). Their systematic presence was demonstrated in all the investigated seafood products, with levels (ΣPCNs in the range 2-440 pg g^-1 wet weight) close to those already reported in other European fish and seafood sampled at a similar period. In addition, the robust measurement of almost all possible PCNs (69/75) allowed a fine interpretation of the observed profiles, highlighting in particular the specificities between species and fishing areas. Compared to the PCDD/Fs, PCBs, and polybrominated diphenylethers levels also measured for this set of samples, PCNs were observed as minor contributors to total concentrations (0.05-3.2%). The specific PCN related dietary dioxin-like exposure could be evaluated at 0.028-0.051 pg of toxic equivalent (TEQ) per kg of body weight per week for an adult, based on fish and seafood consumption only. Overall, this study provides the first baseline data on the occurrence of a large number of PCNs in France, which will allow future evaluation of temporal trends and associated risks.

Mixture Risk Assessment of Complex Real-Life Mixtures-The PANORAMIX Project

Humans are involuntarily exposed to hundreds of chemicals that either contaminate our environment and food or are added intentionally to our daily products. These complex mixtures of chemicals may pose a risk to human health. One of the goals of the European Union's Green Deal and zero-pollution ambition for a toxic-free environment is to tackle the existent gaps in chemical mixture risk assessment by providing scientific grounds that support the implementation of adequate regulatory measures within the EU. We suggest dealing with this challenge by: (1) characterising 'real-life' chemical mixtures and determining to what extent they are transferred from the environment to humans via food and water, and from the mother to the foetus; (2) establishing a high-throughput whole-mixture-based in vitro strategy for screening of real-life complex mixtures of organic chemicals extracted from humans using integrated chemical profiling (suspect screening) together with effect-directed analysis; (3) evaluating which human blood levels of chemical mixtures might be of concern for children's development; and (4) developing a web-based, ready-to-use interface that integrates hazard and exposure data to enable component-based mixture risk estimation. These concepts form the basis of the Green Deal project PANORAMIX, whose ultimate goal is to progress mixture risk assessment of chemicals.

Comparability of Steroid Collision Cross Sections Using Three Different IM-HRMS Technologies: An Interplatform Study

Steroids play key roles in various biological processes and are characterized by many isomeric variants, which makes their unambiguous identification challenging. Ion mobility-mass spectrometry (IM-MS) has been proposed as a suitable platform for this application, particularly using collision cross section (CCS) databases obtained from different commercial IM-MS instruments. CCS is seen as an ideal additional identification parameter for steroids as long-term repeatability and interlaboratory reproducibility of this measurand are excellent and matrix effects are negligible. While excellent results were demonstrated for individual IM-MS technologies, a systematic comparison of CCS derived from all major commercial IM-MS technologies has not been performed. To address this gap, a comprehensive interlaboratory comparison of 142 CCS values derived from drift tube (DTIM-MS), traveling wave (TWIM-MS), and trapped ion mobility (TIM-MS) platforms using a set of 87 steroids was undertaken. Besides delivering three instrument-specific CCS databases, systematic comparisons revealed excellent interlaboratory performance for 95% of the ions with CCS biases within ±1% for TIM-MS and within ±2% for TWIM-MS with respect to DTIM-MS values. However, a small fraction of ions (<1.5%) showed larger biases of up to 7% indicating that differences in the ion conformation sampled on different instrument types need to be further investigated. Systematic differences between CCS derived from different IM-MS analyzers and implications on the applicability for nontargeted analysis are critically discussed. To the best of our knowledge, this is the most comprehensive interlaboratory study comparing CCS from three different IM-MS technologies for analysis of steroids and small molecules in general.

Ion mobility-mass spectrometry to extend analytical performance in the determination of ergot alkaloids in cereal samples

This work evaluates the potential of ion mobility spectrometry (IMS) to improve the analytical performance of current liquid chromatography-mass spectrometry (LC-MS) workflows applied to the determination of ergot alkaloids (EAs) in cereal samples. Collision cross section (CCS) values for EA epimers are reported for the first time to contribute to their unambiguous identification. Additionally, CCS values have been inter-laboratory cross-validated and compared with CCS values predicted by machine-learning models. Slight differences were observed in terms of CCS values for ergotamine, ergosine and ergocristine and their corresponding epimers (from 3.3 to 4%), being sufficient to achieve a satisfactory peak-to-peak resolution for their unequivocal identification. A LC-travelling wave ion mobility (TWIM)-MS method has been developed for the analysis of EAs in barley and wheat samples. Signal-to-noise ratio (S/N) was improved between 2.5 and 4-fold compared to the analog LC-TOF-MS method. The quality of the extracted ion chromatograms was also improved by using IMS.

Optimization and validation of a fast supercritical fluid chromatography tandem mass spectrometry method for the quantitative determination of a large set of PFASs in food matrices and human milk

An Ultra-High Performance Supercritical Fluid Chromatography coupled with tandem Mass Spectrometry analytical method (UHPSFC-MS/MS) was developed for the determination of 34 perfluoroalkylated substances (PFASs) in food-related matrices. Two parameters (i.e. stationary phase and co-solvent) were selected and optimized using a step-by-step method, while a design of experiment (DoE) method using a central composite design (CCD) was implemented to optimize column temperature, mobile phase flow rate, co-solvent concentration and automated back pressure regulator (ABPR). The Torus 2-PIC column was selected along with ammonium acetate AcoNH₄ as additive in the co-solvent. DoE optimization of both peak width and resolution enabled validating an optimized model (desirability 0.613) and setting column temperature at 38.7 °C, AcoNH₄ concentration at 8 mM, mobile phase flow rate of 1.9 mL/min and ABPR at 1654 psi. The validated resulting method enabled reaching limits of quantification below 0.2 ng/g (w.w.) for 97 % PFASs in accordance with current EU requirements. The strategy was successfully applied to the characterization of a range (n > 30) of food-related matrices (red meat, poultry meat, eggs, fish and breast milk) collected in Algeria in 2019. PFOA and PFBA were observed as the most frequently detected PFASs, i.e. in 96.96 % and 90.9 % of the samples respectively. The highest concentrations were determined in fishery products up to 4.42 ng/g (w.w.) for PFTeDA and 0.75 ng/g (w.w.) for PFOS.

Critical evaluation of the role of external calibration strategies for IM-MS

The major benefits of integrating ion mobility (IM) into LC-MS methods for small molecules are the additional separation dimension and especially the use of IM-derived collision cross sections (CCS) as an additional ion-specific identification parameter. Several large CCS databases are now available, but outliers in experimental interplatform IM-MS comparisons are identified as a critical issue for routine use of CCS databases for identity confirmation. We postulate that different routine external calibration strategies applied for traveling wave (TWIM-MS) in comparison to drift tube (DTIM-MS) and trapped ion mobility (TIM-MS) instruments is a critical factor affecting interplatform comparability. In this study, different external calibration approaches for IM-MS were experimentally evaluated for 87 steroids, for which ^TWCCS_N2, ^DTCCS_N2 and ^TIMCCS_N2 are available. New reference CCS_N2 values for commercially available and class-specific calibrant sets were established using DTIM-MS and the benefit of using consolidated reference values on comparability of CCS_N2 values assessed. Furthermore, use of a new internal correction strategy based on stable isotope labelled (SIL) internal standards was shown to have potential for reducing systematic error in routine methods. After reducing bias for CCS_N2 between different platforms using new reference values (95% of ^TWCCS_N2 values fell within 1.29% of ^DTCCS_N2 and 1.12% of ^TIMCCS_N2 values, respectively), remaining outliers could be confidently classified and further studied using DFT calculations and CCS_N2 predictions. Despite large uncertainties for in silico CCS_N2 predictions, discrepancies in observed CCS_N2 values across different IM-MS platforms as well as non-uniform arrival time distributions could be partly rationalized.

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).

Metabolomics and lipidomics to identify biomarkers of effect related to exposure to non-dioxin-like polychlorinated biphenyls in pigs

Recent epidemiological studies show that current levels of exposure to polychlorinated biphenyls (PCBs) remain of great concern, as there is still a link between such exposures and the development of chronic environmental diseases. In this sense, most studies have focused on the health effects caused by exposure to dioxin-like PCBs (DL-PCBs), although chemical exposure to non-dioxin-like PCB (NDL-PCB) congeners is more significant. In addition, adverse effects of PCBs have been documented in humans after accidental and massive exposure, but little is known about the effect of chronic exposure to low-dose PCB mixtures. In this work, exposure to Aroclor 1260 (i.e. a commercially available mixture of PCBs consisting primarily of NDL-PCB congeners) in pigs is investigated as new evidence in the risk assessment of NDL-PCBs. This animal model has been selected due to the similarities with human metabolism and to support previous toxicological studies carried out with more frequently used animal models. Dietary exposure doses in the order of few ng/kg body weight (b.w.) per day were applied. As expected, exposure to Aroclor 1260 led to the bioaccumulation of NDL-PCBs in perirenal fat of pigs. Metabolomics and lipidomics have been applied to reveal biomarkers of effect related to Aroclor 1260 exposure, and by extension to NDL-PCB exposure, for 21 days. In the metabolomics analysis, 33 metabolites have been identified (level 1 and 2) as significantly altered by the Aroclor 1260 administration, while in the lipidomics analysis, 39 metabolites were putatively annotated (level 3) and associated with NDL-PCB exposure. These biomarkers are mainly related to the alteration of fatty acid metabolism, glycerophospholipid metabolism and tryptophan-kynurenine pathway.

Evidence of complementarity between targeted and non-targeted analysis based on liquid and gas-phase chromatography coupled to mass spectrometry for screening halogenated persistent organic pollutants in environmental matrices

This study explored the complementarity between targeted (TS) and non-targeted screening (NTS) based on liquid and gas-phase chromatography coupled to (high-resolution) mass spectrometry (LC-/GC-(HR)MS) for the comprehensive characterization of organohalogen fingerprints within a set of Lake Ontario lake trout samples. The concentrations of 86 legacy, emerging and novel halogenated compounds (HCs), were determined through 4 TS approaches involving no less than 6 hyphenated systems. In parallel, an innovative NTS strategy, involving both LC and GC-Q-Orbitrap, was implemented to specifically highlight halogenated signals. Non-targeted HRMS data were processed under the HaloSeeker software based on Cl and Br isotopic ratio and mass defect to extend the screening to unsuspected and unknown HCs. A total of 195 halogenated mass spectral features were characterized in the Lake Ontario lake trout, including well known HCs (PCBs, PBDEs, PBBs, DDT and their degradation products), emerging HCs (novel brominated flame retardants, short-, medium- and long-chain chlorinated paraffins) or suggested molecular formula (mainly polychlorinated ones). Among the 122 HCs highlighted by TS, only 21 were identified by NTS. These results fueled a discussion on the potential and limitations of both approaches, and the current position of NTS within environmental and health monitoring programs.

The Promise and Challenges of Determining Recombinant Bovine Growth Hormone in Milk

Recombinant bovine growth hormone (rbGH) is produced in large quantities and widely used in a number of countries worldwide to stimulate milk production in dairy animals. The use of this compound in animal production is strictly regulated by food safety directives in force, in particular in the European Union (EU). Although analytical strategies for the detection of rbGH in blood have been successfully reported over the past 15 years, they do not fully answer the expectations of either competent authorities or industrials that would expect measuring its occurrence directly in the milk. As a matrix of excretion but also of consumption, milk appears indeed as the matrix of choice for detecting the use of rbGH in dairy animals. It also allows large volumes to be collected without presenting an invasive character for the animal. However, rbGH detection in milk presents several challenges, mainly related to the sensitivity required for its detection in a complex biological matrix. This review article presents the specific difficulties associated with milk and provides an overview of the analytical strategies reported in the literature and whether they concern indirect or direct approaches to the detection of rbGH administration to animals, with applications either for screening or confirmation purposes.

FROM A NON-TARGETED METABOLOMICS APPROACH TO A TARGETED BIOMARKERS STRATEGY TO HIGHLIGHT TESTOSTERONE ABUSE IN EQUINE. ILLUSTRATION OF A METHODOLOGICAL TRANSFER BETWEEN PLATFORMS AND LABORATORIES

In order to overcome the challenge associated with the screening of Anabolic-Androgenic Steroids (AAS) abuses in animal competitions, a non-targeted LC-HRMS based metabolomics approach was implemented on equine urine samples to highlight potential biomarkers associated with the administration of such compounds, using testosterone esters as model steroids. A statistical model relying on 4 potential biomarkers intensity could be defined to predict the status of the samples. With a routine application perspective, the monitoring of the highlighted potential biomarkers was first transferred into high-throughput LC-SRM. The model's performances and robustness of the approach were preserved and providing a first demonstration of metabolomics-based biomarkers integration within a targeted workflow using common benchtop MS instrumentation. In addition, with a view to the widespread implementation of such biomarker-based tools, we have transferred the method to a second laboratory with similar instrumentation. This proof of concept allows the development and application of biomarker-based strategies to meet current doping control needs.

In vitro assessment of polychlorinated biphenyl bioaccessibility in meat: Influence of fat content, cooking level and consumer age on consumer uptake

In a risk assessment perspective, this work aims to assess the bioaccessibility of PCBs in meat. A standardised in vitro static digestion protocol was set up and coupled with extraction, clean-up and GC × GC-ToF/MS multianalyte method to monitor the fate of PCBs in meat during digestion. Starting with spiked meat, PCB bioaccessibility in 11% fat medium-cooked meat varied in adults from 20.6% to 30.5% according to congeners. PCB bioaccessibility increased to 44.2-50.1% in 5% fat meat and decreased to 6.2-9.1% and to 14.6-19.4% in digestion conditions mimicking infants and elderly, respectively. Intense cooking also decreased PCB bioaccessibility to 18.0-26.7%. Bioaccessibility data obtained with spiked meat were validated with measurements carried out in incurred meat samples. Finally, mean uptake distributions are obtained from a modular Bayesian approach. These distributions feature a lower mode when the fat content is higher, the meat is well-done cooked, and the consumers are older.

Data analysis strategies for the characterization of chemical contaminant mixtures. Fish as a case study

Thousands of chemicals are potentially contaminating the environment and food resources, covering a wide spectrum of molecular structures, physico-chemical properties, sources, environmental behavior and toxic profiles. Beyond the description of the individual chemicals, characterizing contaminant mixtures in related matrices has become a major challenge in ecological and human health risk assessments. Continuous analytical developments, in the fields of targeted (TA) and non-targeted analysis (NTA), have resulted in ever larger sets of data on associated chemical profiles. More than ever, the implementation of advanced data analysis strategies is essential to elucidate profiles and extract new knowledge from these large data sets. Specifically focusing on the data analysis step, this review summarizes the recent progress in integrating data analysis tools into TA and NTA workflows to address the challenging characterization of chemical mixtures in environmental and food matrices. As fish matrices are relevant in both aquatic pollution and consumer exposure perspectives, fish was chosen as the main theme to illustrate this review, although the present document is equally relevant to other food and environmental matrices. The key features of TA and NTA data sets were reviewed to illustrate the challenges associated with their analysis. Advanced filtering strategies to mine NTA data sets are presented, with a particular focus on chemical filters and discriminant analysis. Further, the applications of supervised and unsupervised multivariate analysis methods to characterize exposure to chemical mixtures, and their associated challenges, is discussed.

Nandrolone and estradiol biomarkers identification in bovine urine applying a liquid chromatography high-resolution mass spectrometry metabolomics approach

With the aim of specifically investigating patterns associated with three steroid treatments (17β-nandrolone, 17β-estradiol, and 17β-nandrolone + 17β-estradiol) in bovine, an reversed phase liquid chromatography (RPLC)-electrospray ionization (ESI)(+/-)-high-resolution mass spectrometry (HRMS) study was conducted to characterize the urinary profiles of involved animals. Although specific fingerprints with strong differences could be highlighted between urinary metabolite profiles within urine samples collected on control and treated animals, it appeared further that significant discriminations could also be observed between steroid treatments, evidencing thus specific patterns and candidate biomarkers associated to each treatment. An MS-2 structural elucidation step enabled level-1 identification of two biomarkers mainly involved in energy pathways, in relation to skeletal muscle functioning. These results make it possible to envisage a global strategy for the detection of anabolic practices involving steroids, while at the same time providing clues as to the compounds used, which would facilitate the confirmation stage to follow.

Coupling Complete Blood Count and Steroidomics to Track Low Doses Administration of Recombinant Growth Hormone: An Anti-Doping Perspective

Growth Hormone (GH) under its human recombinant homologue (rhGH), may be abused by athletes to take advantage of its well-known anabolic and lipolytic properties; hence it is prohibited in sports by the World Anti-Doping Agency. Due to the rapid turnover of rhGH, anti-doping screening tests have turned to monitor two endocrine biomarkers (IGF-I and P-III-NP), but unfortunately, they show population-wise variability, limiting the identification rate of rhGH users. Previous studies have evidenced the numerous effects of GH on human physiology, especially in hematopoiesis and steroidogenesis. In this work, aiming to discover novel physiological rhGH biomarkers, we analyzed the complete blood count and the steroidomics profile of healthy, physically active, young males treated either with EPO + rhGH or EPO + placebo. The time-trends of these two physiological routes have been analyzed through geometric trajectory analysis (GTA) and OPLS-DA. Individuals supplemented with micro-doses of rhGH exhibited different leukopoietic and steroidal profiles compared to the control population, suggesting a role of the rhGH in both pathways. In the article, hypotheses on the observed differences are discussed according to the most recent literature and compared to results in animal models. The use of leukopoietic and steroidal biomarkers together with endocrine biomarkers (IGF-1 and P-III-NP) allows to correctly classify over 98% of samples with no false positives, miss-classifying only one single sample (false negative) over a total of 56; a promising result, if compared to the current rhGH detection strategies.

Extending the Lipidome Coverage by Combining Different Mass Spectrometric Platforms: An Innovative Strategy to Answer Chemical Food Safety Issues

From a general public health perspective, a strategy combining non-targeted and targeted lipidomics MS-based approaches is proposed to identify disrupted patterns in serum lipidome upon growth promoter treatment in pigs. Evaluating the relative contributions of the platforms involved, the study aims at investigating the potential of innovative analytical approaches to highlight potential chemical food safety threats. Serum samples collected during an animal experiment involving control and treated pigs, whose food had been supplemented with ractopamine, were extracted and characterised using three MS strategies: Non-targeted RP LC-HRMS; the targeted Lipidyzer™ platform (differential ion mobility associated with shotgun lipidomics) and a homemade LC-HRMS triglyceride platform. The strategy enabled highlighting specific lipid profile patterns involving various lipid classes, mainly in relation to cholesterol esters, sphingomyelins, lactosylceramide, phosphatidylcholines and triglycerides. Thanks to the combination of non-targeted and targeted MS approaches, various compartments of the pig serum lipidome could be explored, including commonly characterised lipids (Lipidyzer™), triglyceride isomers (Triglyceride platform) and unique lipid features (non-targeted LC-HRMS). Thanks to their respective characteristics, the complementarity of the three tools could be demonstrated for public health purposes, with enhanced coverage, level of characterization and applicability.

Accumulation of short-, medium-, and long- chain chlorinated paraffins in tissues of laying hens after dietary exposure

Reliable human health risk assessment associated with chlorinated paraffins (CPs) exposure is limited by the lack of data on the fate of this complex family of contaminants. To gain knowledge on the accumulation and distribution of CPs in biota after ingestion, laying hens were dietary exposed to technical mixtures of short- (SCCPs), medium- (MCCPs), or long-chain (LCCPs) CPs of various chlorine contents during 91 days, at 200 ng/g of feed, each. Adipose tissue, liver, muscle and serum were collected at the steady-state, along with excreta. All C₁₀-C₃₆ CPs were detected in liver. However, differences were observed in CP distribution: LCCPs high %Cl were retained in the liver; LCCPs low %Cl circulated through the serum and were distributed in the different compartments, but were mostly excreted through the eggs; SCCPs and MCCPs were found in all tissues at similar levels. Finally, a mass balance indicated a potential for biotransformation.

Auto-deconvolution and molecular networking of gas chromatography-mass spectrometry data

We engineered a machine learning approach, MSHub, to enable auto-deconvolution of gas chromatography-mass spectrometry (GC-MS) data. We then designed workflows to enable the community to store, process, share, annotate, compare and perform molecular networking of GC-MS data within the Global Natural Product Social (GNPS) Molecular Networking analysis platform. MSHub/GNPS performs auto-deconvolution of compound fragmentation patterns via unsupervised non-negative matrix factorization and quantifies the reproducibility of fragmentation patterns across samples.

Auto-deconvolution and molecular networking of gas chromatography-mass spectrometry data

We engineered a machine learning approach, MSHub, to enable auto-deconvolution of gas chromatography-mass spectrometry (GC-MS) data. We then designed workflows to enable the community to store, process, share, annotate, compare and perform molecular networking of GC-MS data within the Global Natural Product Social (GNPS) Molecular Networking analysis platform. MSHub/GNPS performs auto-deconvolution of compound fragmentation patterns via unsupervised non-negative matrix factorization and quantifies the reproducibility of fragmentation patterns across samples.

Enantiomeric fraction of hexabromocyclododecanes in foodstuff from the Belgian market

Diet is considered a major route of human exposure to hexabromocyclododecane, a chiral environmental contaminant. A previous study reported on the occurrence of hexabromocyclododecane diastereoisomers in food items of animal origin collected in Belgium. The present study reports further results on corresponding enantiomeric fractions of the same samples. None of the samples could be considered as racemic for the α-isomer suggesting that foodstuff contamination occurred prior to death of the corresponding producing animal and was not the result of the food item being in contact with technical HBCDD. Non-racemic chiral signatures were also observed for β- and γ-isomers. We conclude that, depending on their dietary habits, different individuals might be overall exposed to non-racemic profiles. Considering that toxicological effects are enantiomer-dependent, this could modulate potential adverse effects.

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.

Making complex measurements of meat composition fast: Application of rapid evaporative ionisation mass spectrometry to measuring meat quality and fraud

Increasing demands are being placed on meat producers to verify more about their product with regards to safety, quality and authenticity. There are many methods that can detect aspects of these parameters in meat, yet most are too slow to keep up with the demands of modern meat processing plants and supply chains. A new technology, Rapid Evaporative Ionisation Mass Spectrometry (REIMS), has the potential to bridge the gap between advanced laboratory measurements and technology that can screen for quality, safety and authenticity parameters in a single measurement. Analysis with REIMS generates a detailed mass spectral fingerprint representative of a meat sample without the need for sample processing. REIMS has successfully been used to detect species fraud, detect use of hormones in meat animals, monitor meat processing and to detect off flavours such as boar taint. The aim of this review is to summarize these and other applications to highlight the potential of REIMS for meat analysis. Sampling methods and important considerations for data analysis are discussed as well as limitations of the technology and remaining challenges for practical adoption.

Addressing Main Challenges Regarding Short- and Medium-Chain Chlorinated Paraffin Analysis Using GC/ECNI-MS and LC/ESI-MS Methods

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).

Interlaboratory and Interplatform Study of Steroids Collision Cross Section by Traveling Wave Ion Mobility Spectrometry

Collision cross section (CCS) databases based on single-laboratory measurements must be cross-validated to extend their use in peak annotation. This work addresses the validation of the first comprehensive ^TWCCS_N2 database for steroids. First, its long-term robustness was evaluated (i.e., a year and a half after database generation; Synapt G2-S instrument; bias within ±1.0% for 157 ions, 95.7% of the total ions). It was further cross-validated by three external laboratories, including two different TWIMS platforms (i.e., Synapt G2-Si and two Vion IMS QToF; bias within the threshold of ±2.0% for 98.8, 79.9, and 94.0% of the total ions detected by each instrument, respectively). Finally, a cross-laboratory ^TWCCS_N2 database was built for 87 steroids (142 ions). The cross-laboratory database consists of average ^TWCCS_N2 values obtained by the four TWIMS instruments in triplicate measurements. In general, lower deviations were observed between ^TWCCS_N2 measurements and reference values when the cross-laboratory database was applied as a reference instead of the single-laboratory database. Relative standard deviations below 1.5% were observed for interlaboratory measurements (<1.0% for 85.2% of ions) and bias between average values and ^TWCCS_N2 measurements was within the range of ±1.5% for 96.8% of all cases. In the context of this interlaboratory study, this threshold was also suitable for ^TWCCS_N2 measurements of steroid metabolites in calf urine. Greater deviations were observed for steroid sulfates in complex urine samples of adult bovines, showing a slight matrix effect. The implementation of a scoring system for the application of the CCS descriptor in peak annotation is also discussed.

Isolation of homogeneous fractions from wheat water-soluble arabinoxylans. Influence of the structure on their macromolecular characteristics

Water-soluble arabinoxylans from wheat flour were purified and fractionated by graded ethanol precipitation. Six fractions were obtained at 20% (F20), 30% (F30), 40% (F40), 50% (F50), 60% (F60), and 70% (F70) saturation with ethanol. Neutral sugars and (1)H NMR analyses revealed differences in structural characteristics. The Ara/Xyl ratio and the amount of Xylp residues disubstituted increased with ethanol concentration. Ferulic acid content was higher in fractions precipitated at low ethanol percentage. Fractions were refractionated by SEC, leading to 46 subfractions with low polydispersity index. Substitution degree was apparently linearly related to the amount of disubstituted Xylp. Macromolecular characteristics (M(w), [eta], R(G), q, nu) determined by multiangle laser light scattering and viscosimetry were similar among all fractions. A rather flexible conformation was determined for the arabinoxylans, in conflict with the admitted rodlike conformation. The substitution degree had no influence on the conformation or on the rigidity of the polymers. Evidence for the presence of ferulic acid dimers in the water-soluble arabinoxylans is provided, which probably explains the unexpected conformation and macromolecular characteristics.