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

Non-target screening in water analysis: recent trends of data evaluation, quality assurance, and their future perspectives

This trend article provides an overview of recent advancements in Non-Target Screening (NTS) for water quality assessment, focusing on new methods in data evaluation, qualification, quantification, and quality assurance (QA/QC). It highlights the evolution in NTS data processing, where open-source platforms address challenges in result comparability and data complexity. Advanced chemometrics and machine learning (ML) are pivotal for trend identification and correlation analysis, with a growing emphasis on automated workflows and robust classification models. The article also discusses the rigorous QA/QC measures essential in NTS, such as internal standards, batch effect monitoring, and matrix effect assessment. It examines the progress in quantitative NTS (qNTS), noting advancements in ionization efficiency-based quantification and predictive modeling despite challenges in sample variability and analytical standards. Selected studies illustrate NTS's role in water analysis, combining high-resolution mass spectrometry with chromatographic techniques for enhanced chemical exposure assessment. The article addresses chemical identification and prioritization challenges, highlighting the integration of database searches and computational tools for efficiency. Finally, the article outlines the future research needs in NTS, including establishing comprehensive guidelines, improving QA/QC measures, and reporting results. It underscores the potential to integrate multivariate chemometrics, AI/ML tools, and multi-way methods into NTS workflows and combine various data sources to understand ecosystem health and protection comprehensively.

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.

Nontarget Insights into the Fate of Cl-/Br-Containing DOM in Leachate during Membrane Treatment

Halogenated organic compounds in wastewater are persistent and bioaccumulative contaminants of great concern, but few are known at the molecular level. Herein, we focus on nontarget screening of halogenated dissolved organic matter (DOM) in highly concentrated organic matrices of waste leachates and their concentrates. Solid-phase extraction (SPE) was optimized before capturing halogenated signatures via HaloSeeker 2.0 software on mining full-scan high-resolution mass spectrometry (HRMS) fingerprints. This study identified 438 Cl-/Br-containing DOM formulas in 21 leachates and membrane concentrates. Among them, 334 formulas were achieved via SPE with mixed-sorbent cartridges (mixed-SPE), surpassing the 164 formulas achieved through Bond Elut PPL cartridges (PPL-SPE). Herein, only four samples identified via PPL-SPE exhibited a resolution of >50% for extracted Cl-/Br-containing DOM by either SPE. The halogenated DOM constituted 6.87% of the total DOM mass features. Nevertheless, more abundant adsorbable organic halogens deciphered waste leachates and highly concentrated waste streams as reservoirs for halogenated contaminants. Remarkably, 75.7-98.1% of Cl-/Br-containing DOM in primary membrane concentrates remained stable through the secondary membrane treatment, indicating the persistence of these unknown contaminants even post-treatment.

An integrated non-targeted and targeted analysis approach for identification of semi-volatile organic compounds in indoor dust

Household dust contains a wide variety of semi-volatile organic compounds (SVOCs) that may pose health risks. We developed a method integrating non-targeted analysis (NTA) and targeted analysis (TA) to identify SVOCs in indoor dust. Based on a combined use of gas and liquid chromatography with high-resolution mass spectrometry, an automated, time-efficient NTA workflow was developed, and high accuracy was observed. A total of 128 compounds were identified at confidence level 1 or 2 in NIST standard reference material dust (SRM 2585). Among them, 113 compounds had not been reported previously, and this suggested the value of NTA in characterizing contaminants in dust. Additionally, TA was done to avoid the loss of trace compounds. By integrating data obtained from the NTA and TA approaches, SVOCs in SRM 2585 were prioritized based on exposure and chemical toxicity. Six of the top 20 compounds have never been reported in SRM 2585, including melamine, dinonyl phthalate, oxybenzone, diheptyl phthalate, drometrizole, and 2-phenylphenol. Additionally, significant influences of analytical instruments and sample preparation on NTA results were observed. Overall, the developed method provided a powerful tool for identifying SVOCs in indoor dust, which is necessary to obtain a more complete understanding of chemical exposures and risks in indoor environments.

Traceability Research on Dendrobium devonianum Based on SWATHtoMRM

SWATHtoMRM technology was used in this experiment to further identify and trace the sources of Dendrobium devonianum and Dendrobium officinale produced in the same area using TOF and MS-MRM. After the conversion of the R package of SWATHtoMRM, 191 MRM pairs of positive ions and 96 pairs of negative ions were obtained. Dendrobium devonianum and Dendrobium officinale can be separated very well using the PCA and PLS-DA analysis of MRM ion pairs; this shows that there are obvious differences in chemical composition between Dendrobium devonianum and Dendrobium officinale, which clearly proves that the pseudotargeted metabolomics method based on SWATHtoMRM can be used for traceability identification research. A total of 146 characteristic compounds were obtained, with 20 characteristic compounds in Dendrobium devonianum. The enrichment pathways of the characteristic compounds were mainly concentrated in lipids and atherosclerosis, chagas disease, fluid shear stress and atherosclerosis, proteoglycans in cancer, the IL-17 signaling pathway, the sphingolipid signaling pathway, diabetic cardiomyopathy, arginine and proline metabolism, etc., among which the lipid and atherosclerosis pathways were more enriched, and 11 characteristic compounds affected the expression levels of IL-1, TNFα, CD36, IL-1β, etc. These can be used as a reference for research on variety improvement and active substance accumulation in Dendrobium devonianum and Dendrobium officinale.

Occurrence, distribution, and risk assessment of halogenated organic pollutants (HOPs) in marine fish muscle: The case study of Vietnam

Halogenated organic pollutants (HOPs), including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and chlorophenols (CPs), were identified in three marine fish species in Vietnam. Total PCBs, OCPs, and CPs concentrations ranged from 4.5 to 711.6 ng g^-1 lipid weight (lw), 69.9-2360 ng g^-1 lw, and 208.1-3941.2 ng g^-1 lw, respectively. CPs were the most frequently detected pollutants in the marine environment of Vietnam of the three HOPs studied, followed by OCPs and PCBs. There are significant differences in HOPs between three types of seafood in Vietnam, including yellowstripe scad, Indian mackerel, and silver pomfret in this study. Notably, the types and amounts of HOPs found in the fish were differently influenced by the economic and industrial activities of the sampled areas. Despite these findings, the consumption of HOP-contaminated fish from the study areas was found not to pose any significant health risks to Vietnam's coastal population.

Non-target and suspect screening reveal complex pattern of contamination in Arctic marine zooplankton

Although increasing, there is still limited knowledge of the presence of 'contaminants of emerging concern' in Arctic marine biota, particularly in lower trophic species. In the present study, we have applied a novel pipeline to investigate the presence of contaminants in a variety of benthic and pelagic low-trophic organisms: amphipods, copepods, arrow worms and krill. Samples collected in Kongsfjorden in Svalbard in 2018 were subject to extraction and two-dimensional gas chromatography coupled to high-resolution mass spectrometry (GC×GC-HRMS). Tentatively identified compounds included plastic additives, antioxidants, antimicrobials, flame retardants, precursors, production solvents and chemicals, insecticides, and pharmaceuticals. Both legacy contaminants (PAHs, PCBs, PBDEs, hexachlorobenzene) as well as novel and emerging contaminants (triclosan, bisphenol A, and ibuprofen) were quantified in several species using target analysis by GC-MS/MS. The significance of these discoveries is discussed considering the potential for detrimental effects caused by these chemicals, as well as suggested local and distant sources of the components to the Arctic environment.

Thin-layer chromatography coupled with HPLC-DAD/UHPLC-HRMS for target and non-target determination of emerging halogenated organic contaminants in animal-derived foods

In this study, a simple, solvent-saving, and sensitive method was established using high-performance liquid chromatography coupled with high-resolution mass spectrometry to quantitively determine 16 emerging halogenated organic contaminants (HOCs), including polyhalogenated carbazoles, halogenated phenols, and tetrabromobisphenol-A analogs, and to qualitatively identify non-target HOCs in animal-derived food samples. The sample extracts were physically frozen to remove most lipids and further purified by thin-layer chromatography according to the targets polarity. The method detection limit and method quantification limit of 16 HOCs were in the range of 0.003-9.168 and 0.010-30.601 ng·g-1 dry weight, respectively. The recoveries were within 69.1-111.0 %, the intra/inter-day precisions were 0.1-6.1 % and 0.1-6.7 %, and the matrix effects were between -12.1 and 10.8 %, all within the acceptable range. Finally, 16 HOCs were detected in nine actual samples in range of not detected-307.22 ng·g-1 dry weight. Moreover, five bromides and two chlorides were identified by using non-target analysis in animal-derived foods.

Rapid screening of polybrominated diphenyl ethers in water by solid-phase microextraction coupled with ultrahigh-resolution mass spectrometry

Polybrominated diphenyl ethers (PBDEs) are considered emerging organic contaminants that attract more attention in the environment. Herein, online coupling of solid-phase microextraction and ultrahigh-resolution mass spectrometry was developed for rapid screening of eight PBDEs in water samples. This procedure was completed in 22 min, about 6 times faster than the routine workflow such as solid-phase extraction coupled with gas chromatography-mass spectrometry. Thermal desorption and solvent-assisted atmospheric pressure chemical ionization were developed for the effective coupling of solid-phase microextraction (SPME) with ultrahigh-resolution mass spectrometry (UHRMS), which contributed to the signal enhancement and made the methodology feasible for environmental screening. The limits of detection and quantification were 0.01-0.50 ng/mL and 0.05-4.00 ng/mL, respectively. The recoveries were 57.2-75.2% for quality control samples at spiking levels of 0.8-10 ng/mL (4-50 ng/mL for BDE209), with relative standard deviation less than 19.0%. Twelve water samples from different river sites near industrial areas were screened using the developed method. The results showed that BDE-209 was the dominant PBDE (1.02-1.28 ng/mL in positive samples), but its amount was lower than the human health ambient water quality criteria. Consequently, the developed method provides a rapid and reliable way of evaluating contamination status and risks of PBDEs in aqueous environment.

Screening of pesticides and emerging contaminants in eighteen Greek lakes by using target and non-target HRMS approaches: Occurrence and ecological risk assessment

Lakes, albeit ecosystems of vital importance, are insufficiently investigated with respect to the degradation of water quality due to the organic micropollutants load. As regards Greece, screening of lake waters is scarce and concerns a limited number of contaminants. However, understanding the occurrence of contaminants of emerging concern (CECs) and other micropollutants in lakes is essential to appraise their potential ecotoxicological effects. The aim of this study was to deploy a multiresidue screening approach based on liquid chromatography-high-resolution mass spectrometry (HRMS) to get a first snapshot for >470 target CECs, including pesticides, pharmaceuticals, personal care products (PPCPs), per- and polyfluoroalkyl substances (PFASs), as well as organophosphate flame retardants (OPFRs) in eighteen Greek lakes in Central, Northern and West Northern Greece. The omnipresent compounds were DEET (N,N-diethyl-meta-toluamide), caffeine and TCPP (tris (1-chloro-2-propyl) phosphate). Maximum concentrations varied among the different classes. DEET was detected at a maximum average concentration of >1000 ng/L in Lake Orestiada, while its mean concentration was estimated at 233 ng/L. The maximum total concentrations for pesticides, PPCPs, PFASs, and OPFRs were 5807, 2669, 33.1, and 1214 ng/L, respectively, indicating that Greek lakes are still threatened by the intense agricultural activity. Besides, HRMS enabled a non-target screening by exploiting the rich content of the full-scan raw data, allowing the 'discovery' of tentative candidates, such as surfactants, pharmaceuticals, and preservatives among others, without reference standards. The potential ecotoxicity was assessed by both the risk quotient method and ECOSAR (Ecological Structure Activity Relationships) revealing low risk for most of the compounds.

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.

Suzuki C-C Coupling in Paper Spray Ionization: Microsynthesis of Biaryls and High-Sensitivity MS Detection of Aryl Bromides

Suzuki-Miyaura cross-coupling is one of the most powerful strategies for constructing biaryl compounds. However, classic Suzuki-Miyaura coupling suffers from hour-scale reaction time and competitive protodeboronation. To address these problems, a mild nonaqueous potassium trimethylsilanolate (TMSOK)-assisted Suzuki-Miyaura coupling strategy was designed for the microsynthesis of biaryls in paper spray ionization (PSI). Due to the acceleration power facilitated by microdroplet chemistry in reactive PSI, the microsynthesis of biaryls by reactive PSI was accomplished within minutes with comparable yields to the bulk, showing good substrate applicability from 32 Suzuki-Miyaura reactions of aryl bromides and aryl boronic acid/borates bearing different substituents. Based on the above TMSOK-assisted Suzuki-Miyaura coupling strategy, we further developed a high-sensitivity and selective PSI mass spectrometry (MS) method for quantitative analysis of aryl bromides, a class of environmentally persistent organic pollutants that cannot be directly detected by ambient mass spectrometry due to their low ionization efficiency. In situ derivatization of aryl bromides was achieved with aryl borates bearing quaternary ammonium groups in PSI. The proposed PSI-MS method shows good linearity over the 0.01-10 μmol L^-1 range with low detection limits of 1.8-4.8 nmol L^-1 as well as good applicability to the rapid determination of six aryl bromides in three environmental water samples. The proposed PSI-MS method also shows good applicability to brominated flame retardants (polybrominated diphenyls/diphenyl esters). Overall, this study provides a simple, rapid, low-cost, high-sensitivity, and high-selectivity strategy for trace aryl bromides and other brominated pollutants in real samples with minimal/no sample pretreatment.

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.