Exposure science, in its broadest sense, studies the interactions between stressors (chemical, biological, and physical agents) and receptors (e.g. humans and other living organisms, and non-living ...items like buildings), together with the associated pathways and processes potentially leading to negative effects on human health and the environment. The aquatic environment may contain thousands of compounds, many of them still unknown, that can pose a risk to ecosystems and human health. Due to the unquestionable importance of the aquatic environment, one of the main challenges in the field of exposure science is the comprehensive characterization and evaluation of complex environmental mixtures beyond the classical/priority contaminants to new emerging contaminants.
The role of advanced analytical chemistry to identify and quantify potential chemical risks, that might cause adverse effects to the aquatic environment, is essential. In this paper, we present the strategies and tools that analytical chemistry has nowadays, focused on chromatography hyphenated to (high-resolution) mass spectrometry because of its relevance in this field. Key issues, such as the application of effect direct analysis to reduce the complexity of the sample, the investigation of the huge number of transformation/degradation products that may be present in the aquatic environment, the analysis of urban wastewater as a source of valuable information on our lifestyle and substances we consumed and/or are exposed to, or the monitoring of drinking water, are discussed in this article. The trends and perspectives for the next few years are also highlighted, when it is expected that new developments and tools will allow a better knowledge of chemical composition in the aquatic environment. This will help regulatory authorities to protect water bodies and to advance towards improved regulations that enable practical and efficient abatements for environmental and public health protection.
•The role of modern analytical chemistry is essential in exposure science.•Hyphenation of chromatography and HRMS allows the identification of many organic contaminants in the aquatic environment.•Different strategies (target, suspect, non-target) are used for the broad investigation of emerging chemical risks in water.•Monitoring programs and risks assessments are normally focused on parent contaminants.•Little information exists on occurrence and (eco)toxicological effects of transformation products/metabolites in water.
Liquid chromatography coupled to quadrupole‐based tandem mass spectrometry (QqQ) is termed the “gold standard” for bioanalytical applications because of its unpreceded selectivity, sensitivity, and ...the ruggedness of the technology. More recently, however, high‐resolution mass spectrometry (HRMS) has become increasingly popular for bioanalytical applications. Nonetheless, this technique is still viewed, either as a screening technology or as a research tool. Although HRMS is actively discussed during scientific conferences, it is yet to be widely utilised in routine laboratory settings and there remains a reluctance to use HRMS for quantitative measurements in regulated environments. This paper does not aim to comprehensively describe the potential of the latest HRMS technology, but rather, it focuses on what results can be obtained and outlines the author's experiences over a period of many years of the routine application of various forms of HRMS instrumentation. Fifteen years ago, some nine different QqQ methods were used in the author's laboratory to analyse a variety of different veterinary drug resides. Today, many more analytes are quantified by seven HRMS methods and just three QqQ methods remain in use for the analysis of a small set of compounds yet to be upgraded to HRMS analysis. This continual upgrading and migration of analytical methods were accompanied by regularly participating in laboratory proficiency tests (PTs). The PT reports (covering a range of analytes and analytical methods) were used to compare the accuracy of HRMS‐ versus QqQ‐based measurements. In the second part of this paper, the particular strengths and limitations of HRMS for both method development and routine measurements are critically discussed. This also includes some anecdotal experiences encountered when replacing QqQ assays with HRMS methods.
Atmospheric water-soluble organic carbon (WSOC) is a critical component of airborne particulates. It significantly affects the Earth's energy balance, air quality, and human health. Despite its ...importance, the molecular composition and sources of WSOC remain unclear, particularly in non-urban areas. In this study, we collected total suspended particulate (TSP) samples from three sites in northern China: Erenhot (remote site), Zhangbei (rural site), and Jinan (urban site). The WSOC components were analyzed using high-performance liquid chromatography coupled with high-resolution mass spectrometry. The results showed that the formula numbers of identified compounds exhibited a decreasing trend of Jinan (2647) > Zhangbei (2046) > Erenhot (1399). Among the assigned formulas, CHO compounds were the most abundant category for all three sites, accounting for 33 %–38 % of the identified compounds, followed by the CHON compounds with contributions of 27 %–30 %. In the remote site of Erenhot, CHO compounds were dominated by oxidized unsaturated organic compounds, and CHON compounds were mainly low-oxygenated aliphatic compounds, suggesting a significant influence of primary emissions. In contrast, the urban site of Jinan showed higher contributions of CHO and CHON compounds with elevated oxidation degrees, indicating the influence of more extensive secondary oxidation processes. Atmospheric WSOC in Erenhot and Zhangbei had abundant reduced sulfur-containing species, likely from coal or diesel combustion, while that in Jinan was characterized by aliphatic organosulfates and nitrooxy-organosulfates, which are mainly associated with traffic emissions and biogenetic sources, respectively. These findings reveal significant differences in the molecular composition of WSOC in different atmospheric environments and improve our understanding of the chemical properties, potential sources, and transformations of organic aerosols.
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•Atmospheric WSOC from remote, rural, and urban sites were characterized by HPLC-HRMS.•Number of WSOC molecules showed a trend of urban (2647) > rural (2046) > remote (1339).•Molecular weight, oxidation and unsaturation levels of remote WSOC were the lowest.•Secondary processes contributed significantly to WSOC composition in the urban area.•Reduced CHOS and CHONS compounds were predominant in the remote and rural sites.
Surfactants are surface‐active agents widely used in numerous applications in our daily lives as personal care products, domestic, and industrial detergents. To determine complex mixtures of ...surfactants and their degradation products, unselective and rather insensitive methods, based on colorimetric and complexometric analyses are no longer employable. Analytical methodologies able to determine low concentration levels of surfactants and closely related compounds in complex matrices are required. The recent introduction of robust, sensitive, and selective mass spectrometry (MS) techniques has led to the rapid expansion of the surfactant research field including complex mixtures of isomers, oligomers, and homologues of surfactants as well as their chemically and biodegradation products at trace levels. In this review, emphasis is given to the state‐of‐the‐art MS‐based analysis of surfactants and their degradation products with an overview of the current research landscape from traditional methods involving hyphenate techniques (gas chromatography‐MS and liquid chromatography‐MS) to the most innovative approaches, based on high‐resolution MS. Finally, we outline a detailed explanation on the utilization of MS for mechanistic purposes, such as the study of micelle formation in different solvents.
•Structured chromatograms improve reliability of compound identification.•Improved mass spectral quality in pulsed elution-LC × LC-HRMS.•Better understanding retention in the pulsed elution-LC × ...LC.•Improved pulse shape control and accuracy at low pulse volumes.•Flexible method development in pulsed elution-LC × LC.
Due to the decoupling of the first (1D) and second (2D) dimension in pulsed elution-LC × LC (PE-LC × LC), method development is more flexible and straightforward compared to fast comprehensive LC × LC where the dependencies of key parameters between the two dimensions limits its flexibility. In this study we present a method for pulse generation, which is based on a switching valve alternating between one pump that delivers the gradient and a second pump that delivers low eluotrophic strength for the pause state. Consequently, the dwell volume of the system was circumvented and 7.5, and 3.75 times shorter pulse widths could be generated at flow rates of 0.2, and 0.4 mL/min with satisfactory accuracies between programmed and observed mobile phase composition (relative deviation of 6.0 %). We investigated how key parameters including pulse width and step height, 2D gradient time and flow rate affected the peak capacity in PE-LC × LC. The conditions yielding the highest peak capacity for the PE-LC × LC- high-resolution mass spectrometry (HRMS) system were applied to a wastewater effluent sample. The results were compared to a one dimensional (1D)-LC-HRMS chromatogram. The peak capacity increased with a factor 34 from 112 for the 1D-LC run to 3770 for PE-LC × LC-HRMS after correction for undersampling. The analysis time for PE-LC × LC-HRMS was 12.1 h compared to 67.5 min for the 1D-LC-HRMS run. The purity of the mass spectra improved for PE-LC × LC-HRMS by a factor 2.6 (p-value 3.3 × 10−6) and 2.0 (p-value 2.5 × 10−3) for the low and high collision energy trace compared to the 1D-LC-HRMS analysis. Furthermore, the signal-to-noise ratio (S/N) was 4.2 times higher (range: 0.06–56.7, p-value 3.8 × 10−2) compared to the 1D-LC-HRMS separation based on 42 identified compounds. The improvements in S/N were explained by the lower peak volume obtained in the PE-LC × LC-HRMS.
Groundwater is a major drinking water resource, but its quality is threatened by a broad variety of anthropogenic micropollutants (MPs), originating from agriculture, industry, or households, and ...undergoing various transformation processes during subsurface passage. To determine a worst-case impact of pesticide application in agriculture on groundwater quality, a target and suspect screening for more than 300 pesticides and more than 1100 pesticide transformation products (TPs) was performed in 31 Swiss groundwater samples which predominantly originated from areas with intensive agriculture. To assess additional urban contamination sources, more than 250 common urban MPs were quantified. Most of the screened pesticide TPs were experimentally observed by the pesticide producers within the European pesticide registration. To cover very polar pesticide TPs, vacuum-assisted evaporative concentration was used for enrichment, followed by liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). Based on intensity, isotope pattern, retention time, and in silico fragmentation, the suspect hits were prioritised and verified. We identified 22 suspects unequivocally and five tentatively; 13 TPs are reported here for the first time to be detected in groundwater. In 13 out of 31 groundwater samples, the total concentration of the 20 identified and quantified suspects (1 pesticide and 19 pesticide TPs) exceeded the total concentration of the 519 targets (236 pesticides and TPs; 283 urban MPs) for which we screened. Pesticide TPs had higher concentrations than the parent pesticides, illustrating their importance for groundwater quality. The newly identified very polar chlorothalonil TP R471811 was the only compound detected in all samples with concentrations ranging from 3 to 2700 ng/L. Agricultural MP concentration and detection frequency correlated with agricultural land use in the catchment, except for aquifers, where protective top layers reduced MP transport from the surface. In contrast to agricultural MPs, urban MPs displayed almost no correlation with land use. The dominating entry pathway of urban MPs was river bank filtration.
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•Suspect screening in groundwater revealed 13 new pesticide transformation products.•Drinking water quality endangered by chlorothalonil transformation products.•23 of 130 detected compounds (556 quantified) above 0.1 μg/L.•Land use and hydrogeological setting strongly drove micropollutant pattern.
A platform for archiving liquid chromatography high-resolution mass spectrometry (LC-HRMS) data was developed for the retrospective suspect screening of thousands of environmental pollutants with the ...ambition of becoming a European and possibly global standard. It was termed Digital Sample Freezing Platform (DSFP) and incorporates all the recent developments in the HRMS screening methods within the NORMAN Network. In the workflow, raw mass spectral data are converted into mzML, then mass spectral and chromatographic information on thousands of peaks of each sample is extracted into Data Collection Templates. The ‘digitally frozen’ samples can be retrospectively screened for the presence of virtually any compound amenable to LC–MS using a combination of information on its (i) exact mass, (ii) predicted retention time window in the chromatogram, (iii) isotopic fit and (iv) qualifier fragment ions. Its potential was demonstrated on monitoring of 670 antibiotics and 777 REACH chemicals from the Joint Black Sea Surveys (JBSS).
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•An overview of the current HRMS screening steps is presented in an automatized tool.•Digital archiving and retrospective suspect screening were integrated in DSFP.•DSFP enables enhanced data mining and visualization capabilities.•54 seawater, 19 sediment and 12 biota samples were screened for 1447 substances.•80 chemicals from the REACH registry and 12 antibiotics were detected.
Lumacaftor is a transmembrane conductance regulator potentiator drug, prescribed for the treatment of cystic fibrosis in patients who are homozygous for the F508del mutation. Quantitation of ...lumacaftor besides its degradation products and ivacaftor was achieved on a fused‐core silica particle column packed with pentafluorophenylpropyl stationary phase (Ascentis Express F5, 2.7 μm particle size 100 mm × 4.6 mm; Supelco) using gradient elution (A: 0.1% v/v formic acid in water, B: 0.1% v/v formic acid in acetonitrile the mobile phase pH 2.5). A constant flow rate at 1 mL/min was applied, and the detection was realized using a photodiode array detector set at 216 nm. The pseudo tablet formulation of the lumacaftor/ivacaftor fixed‐dose combination preparation, namely, Orkambi®, was prepared in vitro and used for the analytical performance validation and method application studies. In addition, five novel degradation products, four of which even have no Chemical s Services registry number, were identified using high‐resolution mass spectrometry instrument, and their possible mechanisms of formation were proposed. According to current literature, this paper can be regarded as the most comprehensive liquid chromatographic study on lumacaftor determination, among its counterparts.
The formation of chlorinated organic compounds in concrete debris exposed to reactive chlorine was studied to search for markers specific to chlorine gas exposure. Concrete materials of different ...origins were exposed to a range of species of reactive chlorine including bleach, humid and dry chlorine gas at different concentrations. Chlorinated organic compounds in concrete extracts were analysed by targeted gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS) and by non-targeted screening using the corresponding high-resolution techniques (GC-HRMS and LC-HRMS). Overall, different levels and species of chlorinated organic compounds namely chlorophenols, chlorobenzenes, chloromethoxyphenols, chloromethylbenzenes and chloral hydrate were identified in these chlorinated concrete extracts; two examples of diagnostic markers for neat chlorine exposure were trichloromethylbenzene and tetrachlorophenol. The old concrete samples from the 1930s and 1950s had the most chlorinated organic compounds after exposure to neat chlorine gas. Lignin or lignin degradation products were identified as probable candidates for phenolic precursor molecules in the concrete samples. Multivariate data analysis (OPLS-DA) shows distinct patterns for bleach and chlorine exposure. The chlorinated chemicals and specific markers for chlorine gas discovered in our research assist other laboratories in forensic investigations of chlorine gas attacks.
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•Chlorinated markers were detected by non-targeted analysis after chlorine exposure.•Tetrachlorophenol and trichloromethylbenzene are main markers of neat chlorine gas.•The concrete samples from the 1930s and 1950s had the most chlorinated compounds.•Lignin or lignin degradation products are probable phenolic precursors in concrete.•Multivariate data analysis shows distinct patterns for bleach and chlorine exposure.
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•SUPRAS tailoring enhances their applicability in biomass valorization.•Sponge-like SUPRAS of 1,2-octanediol were optimal for extraction of phenolics.•Both highly polar glycoside ...conjugates and less polar polyphenols were extracted.•Total phenolic content was 3 times higher than with ethanol (9.6 ± 0.2 mg GAE/g FW).•SUPRAS were made up of cosmetic authorized ingredients.
Polyphenols are one of the most appreciated antioxidants nowadays. Industry has an enormous interest in their efficient extraction from vegetal biomass, but most of current methods are neither eco-friendly nor cost-effective. Supramolecular solvents (SUPRAS), made up of self-assembled amphiphilic aggregates, have shown a great potential for the extraction of bioactives from biomass as well as for the compliance with many green chemistry criteria. Comparative studies on the extraction capability of different types of SUPRAS are essential for their application-oriented tailoring. In this study, seven SUPRAS made up of reverse hexagonal aggregates and sponge-like structures were synthesized in a variety of hydro-organic mixtures from 1-octanol and 1,2-octanediol, respectively, and their capability for the extraction of polyphenols from raspberries was evaluated. SUPRAS were characterized in terms of formation phase diagrams, composition and structure. Sponge-like SUPRAS of 1,2-octanediol, which had abundant aqueous interconnected channels (35.5–39% w/w), showed excellent solubilisation properties for both the highly polar polyphenol glycoside conjugates and the less polar polyphenols. Optimal values were obtained with SUPRAS of 1,2-octanediol and 1,3-propanediol that provided a total polyphenolic content of 9.57 ± 0.19 mg GAE/g FW sample. This value was up to three times higher than that obtained with ethanolic extracts. Polyphenol glycosides (from quercetin, naringenin, kaempferol, coumaric acid and catechin) were the predominant identified metabolites.
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