HILIC-MS and CE-MS as complementary analytical approaches to assess the impact of exposure to polychlorinated biphenyls on the polar serum metabolome of pigs.

Posted on 7 October, 2024 by fqm302

Hydrophilic interaction liquid chromatography (HILIC) and capillary electrophoresis (CE) coupled to mass spectrometry (MS) are two of the most widely used techniques to explore and characterize the polar metabolome. Both platforms have some peculiar characteristics that make them more suitable for studying different kind of metabolites and different parts of the metabolome. Consequently, their combined use is recommended to extend the coverage of the polar metabolome, particularly when multiple metabolic pathways are expected to be perturbed, as in toxicological studies related to exposure to environmental pollutants such as polychlorinated biphenyls (PCBs). It is unclear whether chronic exposure to low doses leads to effects on the most polar metabolites.

In this work, both HILIC-MS and CE-MS platforms have been used to characterize the polar metabolome of blood serum from pigs exposed to low-doses (20 ng/kg body weight (b.w.)/day) of Aroclor 1260 (a technical mixture of PCBs). The use of both platforms aims to cover large parts of the polar metabolome to better characterize the effects of PCB exposure. The results showed that the combined use of HILIC-MS and CE-MS effectively extended the coverage of the metabolome and the interpretability of the data, highlighting their complementarity in metabolic pathways analysis. The analysis of the polar metabolome evidenced a strong effect of exposure on amino acid metabolism, affecting 10 of the 20 proteic amino acids, and a consistent overflow in the urea cycle.

This work highlights the need to implement analytical multi-platforms to better address metabolomics studies, showing the complementarity of two widely used analytical techniques (i.e. HILIC-MS and CE-MS) to study the polar metabolome in a risk assessment framework.

Posted in Exposomics, HILIC, Metabolomics, PID2020–120020RA-I00, PROYEXCEL_00195, Pig serum, Polychlorinated biphenyls | Tagged , , , | Comments Off on HILIC-MS and CE-MS as complementary analytical approaches to assess the impact of exposure to polychlorinated biphenyls on the polar serum metabolome of pigs.

Analytical challenges and opportunities in the study of endocrine disrupting chemicals within an exposomics framework.

Posted on 29 July, 2024 by fqm302

Exposomics aims to measure human exposures throughout the lifespan and the changes they produce in the human body. Exposome-scale studies have significant potential to understand the interplay of environmental factors with complex multifactorial diseases widespread in our society and whose origin remain unclear. In this framework, the study of the chemical exposome aims to cover all chemical exposures and their effects in human health but, today, this goal still seems unfeasible or at least very challenging, which makes the exposome for now only a concept. Furthermore, the study of the chemical exposome faces several methodological challenges such as moving from specific targeted methodologies towards high-throughput multitargeted and non-targeted approaches, guaranteeing the availability and quality of biological samples to obtain quality analytical data, standardization of applied analytical methodologies, as well as the statistical assignment of increasingly complex datasets, or the identification of (un)known analytes.

This review discusses the various steps involved in applying the exposome concept from an analytical perspective. It provides an overview of the wide variety of existing analytical methods and instruments, highlighting their complementarity to develop combined analytical strategies to advance towards the chemical exposome characterization. In addition, this review focuses on endocrine disrupting chemicals (EDCs) to show how studying even a minor part of the chemical exposome represents a great challenge. Analytical strategies applied in an exposomics context have shown great potential to elucidate the role of EDCs in health outcomes. However, translating innovative methods into etiological research and chemical risk assessment will require a multidisciplinary effort. Unlike other review articles focused on exposomics, this review offers a holistic view from the perspective of analytical chemistry and discuss the entire analytical workflow to finally obtain valuable results.

Posted in Endocrine disrupting chemicals, Exposomics, PROYEXCEL_00195, Review | Tagged | Comments Off on Analytical challenges and opportunities in the study of endocrine disrupting chemicals within an exposomics framework.

Assessing human exposure to pesticides and mycotoxins: optimization and validation of a method for multianalyte determination in urine samples.

Posted on 9 April, 2024 by fqm302

Humans are exposed to an increasing number of contaminants, with diet being one of the most important exposure routes. In this framework, human biomonitoring is considered the gold standard for evaluating human exposure to chemicals. Pesticides and mycotoxins are chemicals of special concern due to their health implications. They constitute the predominant border rejection notifications for food and feed in Europe and the USA. However, current biomonitoring studies are focused on a limited number of compounds and do not evaluate mycotoxins and pesticides together. In this study, an analytical method has been developed for the determination of 30 pesticides and 23 mycotoxins of concern in urine samples. A salting-out liquid–liquid extraction (SALLE) procedure was optimized achieving recoveries between 70 and 120% for almost all the compounds and limits as lower as when QuEChERS was applied. The compounds were then determined by liquid chromatography coupled to triple quadrupole mass spectrometry. Different chromatographic conditions and analytical columns were tested, selecting a Hypersild gold aQ column as the best option. Finally, the method was applied to the analysis of 45 urine samples, in which organophosphate and pyrethroid pesticides (detection rates (DR) of 82% and 42%, respectively) and ochratoxin A and deoxynivalenol (DR of 51% and 33%, respectively) were the most detected compounds. The proposed analytical method involves the simultaneous determination of a diverse set of pesticides and mycotoxins, including their most relevant metabolites, in human urine. It serves as an essential tool for biomonitoring the presence of highly prevalent contaminants in modern society.

Posted in Biomonitoring, Mass spectrometry, Mycotoxins, PID2021-127804OB-I00, PROYEXCEL_00195, Pesticides, SALLE, UHPLC, Urine | Tagged , , | Comments Off on Assessing human exposure to pesticides and mycotoxins: optimization and validation of a method for multianalyte determination in urine samples.

Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples.

Posted on 24 January, 2024 by fqm302

Cyanotoxins constitute a group of toxic secondary metabolites, the presence of which in any water body poses a major health risk. Moreover, advanced organisms such as edible plants exposed to these toxins, are a possible pathway for human exposure. Green analytical chemistry is demanding environmentally friendly analytical techniques. In this sense, we propose the use of capillary electrophoresis coupled to tandem mass spectrometry (CE-MS/MS) to determine a mixture of eight cyanotoxins belonging to three different classes: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin and anatoxin-a) and three isomeric non-protein amino acids (β-methylamino-l-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). Separation was achieved by using an acidic background electrolyte consisting of 2 M formic acid and 20% acetonitrile in water. Parameters affecting MS/MS detection and the sheath-liquid interface were also studied. Finally, a combination of pH-junction, field-amplified sample stacking (FASS) and acid barrage as online preconcentration strategies, was employed to improve sensitivity and efficiency. The online preconcentration applied, in combination with a dual cartridge solid-phase extraction (SPE) system, allows to obtain limits of detection in the very low range of µg·L−1 for these multiclass cyanotoxins in reservoir water samples (from 0.005 to 0.10 µg·L−1). Furthermore, for the first time cyanotoxins are analysed in spinach samples through CE-MS/MS using the same SPE procedure, following lyophilisation and solid-liquid extraction with 6 mL 80 % aqueous MeOH.

Posted in CZE, Cyanotoxins, FASS, Mass spectrometry, PID2021-127804OB-I00, SPE, Spinach, Water, acid barrage, pH-junction | Tagged , , , | Comments Off on Capillary electrophoresis tandem mass spectrometry to determine multiclass cyanotoxins in reservoir water and spinach samples.

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

Posted on 22 December, 2023 by fqm302

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.

Posted in Liquid-liquid extraction, Mass spectrometry, Metabolomics, PID2020–120020RA-I00, Pig serum, Polychlorinated biphenyls, UHPLC | Tagged , , , | Comments Off on Determination of bile acids in serum of pigs exposed to polychlorinated biphenyls by liquid chromatography-mass spectrometry.

Mycotoxin occurrence in milk and durum wheat samples from Tunisia using dispersive liquid–liquid microextraction and liquid chromatography with fluorescence detection.

Posted on 30 October, 2023 by fqm302

Food and feed contamination with mycotoxins is a major public health concern. Humans and animals are exposed to these toxins by consuming contaminated products throughout their lives. In this study, a method based on dispersive liquid–liquid microextraction (DLLME), followed by liquid chromatography with fluorescence detection (LC-FLD), was validated for the determination of aflatoxins (AFs) M1, B1, B2, G1, G2, zearalenone (ZEN), and ochratoxin A (OTA). The method was applied to 150 raw cow milk samples and 90 market durum wheat samples from two Tunisian climatic regions: the littoral region (Mahdia) and the continental region (Béja). This work was carried out to obtain more surveillance data to support rapid initiatives to assure safe foods and protect consumer health and to estimate the daily exposure of the Tunisian population consuming those products. AFG2 and OTA were found in wheat with incidences of 54.4 and 11.1%, respectively. On the other side, milk samples were contaminated by AFG2, AFB1, and AFB2 with incidences of 8.7%, 2.0%, and 0.67%, respectively. Some of the samples showed OTA concentrations above the maximum limit allowed by the European Union, which represents a health risk for consumers in Tunisia, where no legislation exists about the maximum content of mycotoxins in food.

Posted in Aflatoxins, DLLME, Durum wheat, Fluorescence, Milk, Mycotoxins, PID2021-127804OB-I00, PROYEXCEL_00195, Photo-induced, UHPLC | Tagged , , | Comments Off on Mycotoxin occurrence in milk and durum wheat samples from Tunisia using dispersive liquid–liquid microextraction and liquid chromatography with fluorescence detection.

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

Posted on 6 September, 2023 by fqm302

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.

Posted in Contaminants, GC, Mass spectrometry, Metabolomics, PID2020–120020RA-I00, Pig serum, Polychlorinated biphenyls | Tagged , , | Comments Off on Deeper insights into the effects of low dietary levels of polychlorinated biphenyls on pig metabolism using gas chromatography-high resolution mass spectrometry metabolomics.

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

Posted on 6 August, 2023 by fqm302

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.

Posted in CZE, HILIC, Human serum, Metabolomics, PID2020–120020RA-I00, PROYEXCEL_00195 | Tagged , , | Comments Off on A comparison of hydrophilic interaction liquid chromatography and capillary electrophoresis for the metabolomics analysis of human serum.

Analytical methods based on liquid chromatography and capillary electrophoresis to determine neonicotinoid residues in complex matrices. A comprehensive review.

Posted on 30 July, 2023 by fqm302

Neonicotinoids (NNIs) are neuro-active and systemic insecticides widely used to protect crops from pest attack. During the last decades, there has been an increase concern about their uses and toxic effects, especially to beneficial and non-target insects such as pollinators. To assess potential health hazards and the environmental impacts derived from NNIs uses, a great variety of analytical procedures for the determination of their residues and their metabolites at trace level in environmental, biological and food samples have been reported. Due to the complexity of the samples, efficient sample pretreatment methods have been developed, which include mostly clean-up and preconcentration steps. On the other hand, among the analytical techniques used for their determination, high-performance liquid chromatography (HPLC) coupled to ultraviolet (UV) or mass spectrometry (MS) detection is the most widely used, although capillary electrophoresis (CE) has also been employed in the last years, considering some improvements in sensitivity when coupling with new MS detectors. In this review, we present a critical overview of analytical methods based on HPLC and CE reported in the last decade, discussing relevant and innovative sample treatments for the analysis of environmental, food and biological samples.

Posted in B-AGR-202-UGR20, Chromatography, Electrophoresis, Neonicotinoids, Review | Tagged | Comments Off on Analytical methods based on liquid chromatography and capillary electrophoresis to determine neonicotinoid residues in complex matrices. A comprehensive review.

Determination of multiclass cyanotoxins in blue-green algae (BGA) dietary supplements using hydrophilic interaction liquid chromatography-tandem mass spectrometry.

Posted on 7 February, 2023 by fqm302

In recent years, the consumption of blue-green algae (BGA) dietary supplements is increasing because of their health benefits. However, cyanobacteria can produce cyanotoxins, which present serious health risks. In this work we propose hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) to determine cyanotoxins in BGA dietary supplements. Target toxins, including microcystin-leucine-arginine (MC-LR) and microcystin-arginine-arginine (MC-RR), nodularin, anatoxin-a and three non-protein amino acids, β-N-methylamino-L-alanine (BMAA), 2,4-diaminobutyric acid (DAB) and N-(2-aminoethyl)glycine (AEG), were separated using a SeQuant ZIC-HILIC column. Cyanotoxin extraction was based on solid–liquid extraction (SLE) followed by a tandem-solid phase extraction (SPE) procedure using Strata-X and mixed-mode cation-exchange (MCX) cartridges. The method was validated for BGA dietary supplements obtaining quantification limits from 60 to 300 µg·kg−1. Nine different commercial supplements were analyzed, and DAB, AEG, and MCs were found in some samples, highlighting the relevance of monitoring these substances as precaution measures for the safe consumption of these products.

Posted in B-AGR-202-UGR20, Blue-green algae, Cyanotoxins, HILIC, Mass spectrometry, RTI2018-097043-B-I00, SPE | Tagged , , | Comments Off on Determination of multiclass cyanotoxins in blue-green algae (BGA) dietary supplements using hydrophilic interaction liquid chromatography-tandem mass spectrometry.