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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., (© 2024. The Author(s).)

A fundamental step in addressing the global problem of mycotoxins is the development of highly sensitive, multi-class extraction and detection methods. This constitutes a field of research that has in recent years enjoyed a steady advance. Such methods, generally based on liquid chromatography coupled to mass spectrometry, are widely reported successfully detecting various mycotoxins in different food and feed samples. In this work, an innovative approach to multi-class mycotoxin control is proposed, offering specific advantages: a broader inclusion of more mycotoxin classes, robust and thorough extraction for all target compounds despite their varied chemical properties, and determination of all analytes from a single injection. The method involved the extraction and quantification of the main mycotoxins produced by Aspergillus, Fusarium, and Penicillium fungi, as well as their reported derivatives, together with 12 other compounds most commonly produced by Claviceps purpurea. The popularly reported QuEChERS technique has been reduced to a simple "salting-out liquid-liquid extraction" (SO-LLE) to obtain the most efficient extraction of the aforementioned mycotoxin classes in a very short time. This is in particular extremely important in ensuring correct determination of individual ergot alkaloids, for which short and robust sample preparation as well as short analytical sequences were key for minimizing the epimerization during analysis. The analyses of wheat and maize samples were performed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. Matrix-matched calibration curves were established and limits of quantification were below the maximum levels established by the EU regulation. The precision (repeatability and intermediate precision) was lower than 13% in all cases and recoveries ranged between 60 and 98% in maize and between 62 and 103% in wheat, fulfilling the current legislation. The method was applied to study the co-occurrence of these mycotoxins in wheat (n = 13) and maize (n = 15) samples from six European countries. A successful quantification of 23 different mycotoxins, from all major classes, in 85% of wheat and 93% of maize samples was achieved.

Ochratoxin A (OTA) is a mycotoxin naturally found in various foods, including wine. As OTA is considered as a possible human carcinogen, the maximum concentration for this compound has been established at 2 μg kg(-1) in wine by the EU (Directive (CE) No 1881/2006). Typically, immunoaffinity columns have been used for its extraction. However, simpler, more efficient and less contaminant extraction systems are demanding. In this work, dispersive liquid-liquid microextraction using ionic liquid as extractant solvent (IL-DLLME) and the QuEChERS procedure, have been evaluated and compared for extraction of OTA in wine samples. Laser-induced fluorescence (LIF, He-Cd Laser excitation at 325 nm) coupled with capillary HPLC has been used for the determination of OTA, using a sodium dodecyl sulfate micellar solution in the mobile phase to increase the fluorescence intensity. Matrix-matched calibration curves were established for both methods, obtaining LODs (3× S/N) of 5.2 ng·L(-1) and 85.7 ng·L(-1) for IL-DLLME and QuEChERS, respectively. Clean extracts were obtained for white, rose and red wines with both methods, with recoveries between 88.7-94.2% for IL-DLLME and between 82.6-86.2% for QuEChERS. The precision was evaluated in terms of repeatability (n = 9) and intermediate precision (n = 15), being ≤ 8.5% for IL-DLLME and ≤ 5.4% for QuEChERS.

Dispersive liquid-liquid microextraction (DLLME) has been proposed for the extraction and preconcentration of 12 carbamate pesticides in juice samples, followed by their determination by micellar electrokinetic chromatography with diode-array detection. To improve sensitivity, an on-capillary sample concentration method based on sweeping has been developed. Also, separations were performed in an extended light path fused-silica capillary; the separation buffer consisted of 100 mM borate and 50 mM SDS (pH 9.0) with 5% acetonitrile. Samples were introduced by hydrodynamic injection, dissolved in the separation buffer, but free of micelles. Several parameters of the DLLME procedure (such as type and volume of extraction and dispersive solvents, pH, salt addition, and extraction time) were optimized. Recoveries obtained for fortified juice samples (banana, pineapple, and tomato) at three different concentration levels, ranged from 78% to 105%, with relative standard deviations lower than 9%. The limits of detection ranged from 1 to 7 μg l(-1). Moreover, the method is fast, simple, and environmentally friendly.

A sensitive capillary electrophoresis-laser-induced fluorescence method has been developed for the determination of six fluoroquinolones of human (ofloxacin, lomefloxacin, and norfloxacin) and veterinary use (danofloxacin, enrofloxacin, and sarafloxacin) in different kinds of water. Fluorescence detection was achieved using a He-Cd laser, with a wavelength of 325 nm. Separation was performed in a fused-silica capillary, and conditions were optimized to obtain the most adequate separation and with the best sensitivity. The separation was carried out in a 70-cm-long capillary (75 microm internal diameter, effective length 55 cm) by using a 125 mM phosphoric acid separation buffer at pH 2.8, with 36% of methanol. The water sample pretreatment involved the separation and preconcentration of the analytes by solid phase extraction. Two reverse-phase cartridges have been evaluated, namely Oasis hydrophilic-liphophilic balance and Strata-X; the latter provided the best recoveries for the selected analytes. The method shows very low detection limits (0.3-1.9 ng/L) with acceptable recoveries and precisions and has been successfully applied to the analysis of well and tap water samples.

In this paper we review applications of capillary electrophoresis (CE) to the determination of antibiotic residues in food derived from animals and in environmental samples. Although many CE methods have been used to determine antibiotics in the pharmaceutical field (drug quality control or therapeutic monitoring in biological samples), food and environmental applications have been increasing in recent years. Due to the maximum residue limits established by the EU, in Directive 2377/90/EEC, for foodstuffs of animal origin and considering the low levels that can be found in environmental or waste waters or soils, different strategies to increase sensitivity have been developed, including off-line preconcentration, on-line stacking modes to use higher sample volumes, or in-line solid-phase extraction. Also, several detection techniques, such as fluorescence, laser-induced fluorescence, electrochemical detection, or mass spectrometry have been used; the last of these also enables unequivocal identification of the residues, required by Commission Decision 2002/657/EC. All these aspects will be discussed in this paper, in relation to the main groups of antibiotics used in veterinary and human medicine, for which applications in food and environmental samples have been developed by using CE as an efficient alternative to liquid chromatography.

A new strategy is proposed for verifying if recovery factor is constant and independent of the real analyte content of samples. A signal-recovery function has been developed on the basis of measurement of spiked test samples before and after a pre-treatment step and considering, as starting point, a recent IUPAC recommendation which distinguishes between two terms--recovery factor, R, and apparent recovery, R*. Apparent recovery includes recovery factor and a new recovery term proposed in a previous paper by the authors, named calibration recovery, R(C). The signal-recovery function is obtained directly from the measured analytical signals instead of from the concentrations, simplifying the calculations. A linear signal-recovery curve indicates that the recovery factor is constant in the analyte concentration range studied experimentally and, in this way, a single recovery factor can be calculated. The usefulness of the proposed method has been shown by quantification of the pesticide carbaryl by two different flow-injection analysis methods with chemiluminescent detection based on the luminol and TCPO systems. Good results were obtained from both methods.