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 | 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 | 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.

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

Posted on 26 September, 2022 by fqm302

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.

Posted in Barley, Ergot alkaloids, Ion mobility, PID2021-127804OB-I00, QuEChERS, UHPLC, Wheat | Tagged , , | Comments Off on Ion mobility-mass spectrometry to extend analytical performance in the determination of ergot alkaloids in cereal samples.

Non-aqueous capillary electrophoresis–time of flight mass spectrometry method to determine emerging mycotoxins.

Posted on 26 September, 2022 by fqm302

Enniatins (ENN) and beauvericin (BEA) are emerging mycotoxins that have been traditionally determined by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). However, to the best of our knowledge, no analytical methods based on capillary electrophoresis (CE)–MS/MS have been reported so far. Due to their non-polar nature, in this work, a non-aqueous CE (NACE) method coupled to quadrupole time-of-flight–MS is proposed for the first time to identify and quantify these mycotoxins. Determination was achieved in 4 min under optimum conditions: 40 mM ammonium acetate in 80:20 (v/v) acetonitrile-methanol (buffer), 30 kV (voltage), 80 cm (capillary length), 20 °C (capillary temperature) and 50 mbar × 30 s (injection). Higher selectivity can be achieved when compared with LC due to the formation of exclusive CE adducts such as [M + CH3CH2NH3]+. “All Ions” acquisition mode was selected as it allows the quantification of the usual ENNs, as well as the identity confirmation of less common ENNs.

The method was validated for wheat samples, obtaining limits of quantification from 4.0 to 8.3 μg/kg depending on the emerging mycotoxin, recovery values higher than 87.4%, and intra- and inter-day precision values (RSDs) lower than 15.1% in all cases. Finally, 29 wheat samples were analyzed, finding 26 samples with concentrations of enniatin B higher than the limit of quantification (7.5–1480 μg/kg), 20 for enniatin B1 (5.2–550 μg/kg), 7 for enniatin A (10–55 μg/kg), 4 for enniatin A1 (12.6–77 μg/kg) and 5 for BEA (9.2–16.4 μg/kg). Moreover, two other ENNs were tentatively identified.

Posted in B-AGR-202-UGR20, EQC2018-004453-P, Enniatins, Mass spectrometry, Mycotoxins, NACE, RTI2018-097043-B-I00, SALLE, Wheat | Tagged , , | Comments Off on Non-aqueous capillary electrophoresis–time of flight mass spectrometry method to determine emerging mycotoxins.

Sweeping-micellar electrokinetic chromatography with tandem mass spectrometry as an alternative methodology to determine neonicotinoid and boscalid residues in pollen and honeybee samples.

Posted on 19 April, 2022 by fqm302

In this work, it is proposed for the first time an electrophoretic approach based on micellar electrokinetic chromatography coupled with tandem mass spectrometry (MEKC-MS/MS) for the simultaneous determination of nine neonicotinoids (NNIs) together with the fungicide boscalid in pollen and honeybee samples. The separation was performed using ammonium perfluorooctanoate (50 mM, pH 9) as both volatile surfactant and electrophoretic buffer compatible with MS detection. A stacking strategy for accomplishing the on-line pre-concentration of the target compounds, known as sweeping, was carried out in order to improve separation efficiency and sensitivity. Furthermore, a scaled-down QuEChERS was developed as sample treatment, involving a lower organic solvent consumption and using Z-Sep+ as dispersive sorbent in the clean-up step. Regarding the detection mode, a triple quadrupole mass spectrometer was operating in positive ion electrospray mode (ESI+) under multiple reaction monitoring (MRM). The main parameters affecting MS/MS detection as well as the composition of the sheath-liquid (ethanol/ultrapure water/formic acid, 50:49.5:0.5 v/v/v) and other electrospray variables were optimized in order to achieve satisfactory sensitivity and repeatability. Procedural calibration curves were established in pollen and honeybee samples with LOQs below 11.6 µg kg−1 and 12.5 µg kg−1, respectively. Precision, expressed as RSD, lower than 15.2% and recoveries higher than 70% were obtained in both samples. Two positive samples of pollen were found, containing imidacloprid and thiamethoxam. Imidacloprid was also found in a sample of honeybees. The obtained results highlight the applicability of the proposed method, being an environmentally friendly, efficient, sensitive and useful alternative for the determination of NNIs and boscalid in pollen and honeybee samples.

Posted in B-AGR-202-UGR20, EQC2018-004453-P, Honeybees, Insects, MEKC, Mass spectrometry, Neonicotinoids, Pesticides, Pollen, QuEChERS, RED2018-102522-T, RTI2018-097043-B-I00, Sweeping | Tagged , , , | Comments Off on Sweeping-micellar electrokinetic chromatography with tandem mass spectrometry as an alternative methodology to determine neonicotinoid and boscalid residues in pollen and honeybee samples.

Multiclass cyanotoxin analysis in reservoir waters: Tandem solid-phase extraction followed by zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry.

Posted on 29 November, 2021 by fqm302

The presence of cyanobacteria and cyanotoxins in all water bodies, including ocean water and fresh water sources, represents a risk for human health as eutrophication and climate change are enhancing their level of proliferation. For risk assessment and studies on occurrence, the development of reliable and sensitive analytical approaches able to cover a wide range of cyanotoxins is essential. This work describes the development of an HILIC-MS/MS multiclass method for the simultaneous analysis of eight cyanotoxins in reservoir water samples belonging to three different classes according to their chemical structure: cyclic peptides (microcystin-LR, microcystin-RR and nodularin), alkaloids (cylindrospermopsin, anatoxin-a) and three non-protein amino acids isomers such as β-methylamino-L-alanine, 2,4-diaminobutyric acid and N-(2-aminoethyl)glycine). A SeQuant ZIC-HILIC column was employed to achieve the chromatographic separation in less than 12 min. Previously, a novel sample treatment based on a tandem solid-phase extraction (SPE) system using mixed cation exchange (MCX) and Strata-X cartridges was investigated with the aim of extracting and preconcentrating this chemically diverse group of cyanotoxins. The Strata-X cartridge, which was configured first in the line of sample flow, retained the low polar compounds and the MCX cartridge, which was at the bottom of the dual system, retained mainly the non-protein amino acids. The optimization procedure highlighted the importance of sample ion content for the recoveries of some analytes such as the isomers β-N-methylamino-L-alanine and 2-4-diaminobutyric acid. Method validation was carried out in terms of linearity, limit of detection (LOD) and quantification (LOQ), recoveries, matrix effect and precision in terms of repeatability and intermediate precision. This work represents the first analytical method for the simultaneous analysis of these multiclass cyanotoxins in reservoir water samples, achieving LOQs in the very low range of 7·10−3 – 0.1 μg L−1. Despite high recoveries obtained at the LOQ concentration levels (101.0–70.9%), relative standard deviations lower than 17.5% were achieved.

Posted in Cyanotoxins, HILIC, Mass spectrometry, RTI2018-097043-B-I00, SPE, Water | Tagged , , | Comments Off on Multiclass cyanotoxin analysis in reservoir waters: Tandem solid-phase extraction followed by zwitterionic hydrophilic interaction liquid chromatography-mass spectrometry.

A natural deep eutectic solvent as a novel dispersive solvent in dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of pesticide residues.

Posted on 17 November, 2021 by fqm302

Current trends in analytical chemistry encourage the use of innocuous solvents to develop modern methods aligned with green chemistry. In this sense, natural deep eutectic solvents (NADESs) have emerged as a novel generation of green solvents which can be employed in sample treatments as an alternative to the toxic organic solvents commonly used so far. In this work, a new extraction method employs dispersive liquid-liquid microextraction based on a solid floating organic droplet (DLLME-SFO), by using a mixture composed of a less dense than water extraction solvent, 1-dodecanol, and a novel dispersive solvent, NADES. The methodology was proposed to extract and preconcentrate some pesticide residues (fipronil, fipronil-sulfide, fipronil-sulfone, and boscalid) from environmental water and white wine samples before analysis by liquid-chromatography coupled to ultraviolet detection (HPLC-UV). Limits of quantification (LOQs) lower than 4.5 μg L−1, recoveries above 80%, and precision, expressed as RSD, below 15% were achieved in both samples showing that the proposed method is a powerful, efficient, and green alternative for the determination of these compounds and, therefore, demonstrating a new application for NADES in sample preparation. In addition, the DLLME-SFOD-HPLC-UV method was evaluated and compared with other reported approaches using the Analytical GREEnness metric approach, which highlighted the greenness of the proposed method.

Posted in Fipronil, HPLC, NADES, RED2018-102522-T, UV-vis, Water, Wine | Tagged , | Comments Off on A natural deep eutectic solvent as a novel dispersive solvent in dispersive liquid-liquid microextraction based on solidification of floating organic droplet for the determination of pesticide residues.