Examinando por Autor "Casado, Natalia"

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A Miniaturized QuEChERS Method Combined with Ultrahigh Liquid Chromatography Coupled to Tandem Mass Spectrometry for the Analysis of Pyrrolizidine Alkaloids in Oregano Samples
(MDPI, 2020) Izcara, Sergio; Casado, Natalia; Morante-Zarcero, Sonia; Sierra, Isabel
Recent and unexpected food alerts about relatively high amounts of pyrrolizidine alkaloids in oregano samples have stressed the need to develop analytical strategies to ensure food safety in this type of foodstu . Accordingly, this work presents the development of a miniaturized strategy based on the QuEChERS (quick, easy, cheap, e ective, rugged and safe) method combined with ultrahigh liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) for the determination of 21 pyrrolizidine alkaloids suggested by the European Food Safety Authority to be monitored in food. The analytical method was properly validated, with overall average recoveries from 77 to 96% and relative standard deviations <13% (n = 9). The method proved to be a sustainable analytical strategy which meets green analytical chemistry principles as it showed good performance by using small amounts of sample (0.2 g), organic solvents (1000 L), clean-up sorbents (175 mg) and partitioning salts (0.65 g). Its feasibility was verified through the analysis of 23 oregano samples. Of the samples analyzed, 100% were contaminated, with an average concentration of 1254 g/kg. Lasiocarpine, lasiocarpine N-oxide, europine, europine N-oxide, senecivernine, senecionine, echimidine N-oxide, lycopsamine N-oxide and intermedine N-oxide were the alkaloids which significantly contributed to the contamination of the samples.
An improved and miniaturized analytical strategy based on μ-QuEChERS for isolation of polyphenols. A powerful approach for quality control of baby foods
(Elsevier, 2018-02-22) Casado, Natalia; Perestrelo, Rosa; L. Silva, Catarina; Sierra, Isabel; S. Câmara, José
An improved and miniaturized quick, easy, cheap, effective, rugged and safe (μ-QuEChERS) strategy combined with ultra-high pressure liquid chromatography coupled to a photodiode array detection system (UHPLC-PDA) was developed and optimized for the determination of twelve polyphenols in different baby foods samples. The proposed analytical approach proved to be highly cost-effective and environmentally friendly, since it showed good extraction efficiency using few amounts of sample (0.3 g), organic solvents (1000 μL), clean-up sorbents (87.5 mg) and partitioning salts (0.2 g), producing minimal waste disposal and reducing analysis time. Method performance was validated in terms of selectivity, linearity, limits of detection and quantification, matrix effects, precision and accuracy using different baby food matrices according to their composition. The overall average recoveries ranged from 71 to 100% with relative standard deviations lower than 6% (n = 18). The method was successfully applied to commercial baby food samples (including pureed solids, juices and porridges), and their total phenolic content (TPC) and antioxidant capacity (RSA) were also investigated. Results allowed characterizing the abundance of the selected polyphenols in the samples, and the highest RSA and TPC were found in the fruit-based baby foods. Thus, this work represents a first approach to determine the nutritional quality of these products.
Application of a hybrid ordered mesoporous silica as sorbent for solid-phase multi-residue extraction of veterinary drugs in meat by ultra-high-performance liquid chromatography coupled to ion-trap tandem mass spectrometry
(Elsevier, 2016-06) Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel
A quick, sensitive and selective analytical reversed-phase multi-residue method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) operating in both positive and negative ion mode was developed for the simultaneous determination of 23 veterinary drug residues (ß-blockers, ß-agonists and Non-Steroidal Anti-inflammatory Drugs (NSAIDs)) in meat samples. The sample treatment involved a liquid-solid extraction followed by a solid-phase extraction (SPE) procedure. SBA-15 type mesoporous silica was synthetized and modified with octadecylsilane, and the resulting hybrid material (denoted as SBA-15-C18) was applied and evaluated as SPE sorbent in the purification of samples. The materials were comprehensively characterized, and they showed a high surface area, high pore volume and a homogeneous distribution of the pores. Chromatographic conditions and extraction procedure were optimized, and the method was validated according to the Commission Decision 2002/657/EC. The method detection limits (MDLs) and the method quantification limits (MQLs) were determined for all the analytes in meat samples and found to range between 0.01-18.75 ¿g/Kg and 0.02-62.50 ¿g/Kg, respectively. Recoveries for 15 of the target analytes ranged from 71-98%. In addition, for comparative purpose SBA-15-C18 was evaluated towards commercial C18 amorphous silica. Results revealed that SBA-15-C18 was clearly more successful in the multi-residue extraction of the 23 mentioned analytes with higher recovery values. The method was successfully tested to analyze prepacked preparations of mince bovine meat. Traces of propranolol, ketoprofen and diclofenac were detected in some samples.
Application of the QuEChERS Strategy as a Useful Sample Preparation Tool for the Multiresidue Determination of Pyrrolizidine Alkaloids in Food and Feed Samples: A Critical Overview
(MDPI, 2022) Casado, Natalia; Morante-Zarcero, Sonia; Sierra, Isabel
The identification of concerning high levels of pyrrolizidine alkaloids (PAs) in a wide variety of food products has raised the occurrence of these natural toxins as one of the main current issues of the food safety field. Consequently, a regulation with maximum concentration levels of these alkaloids has recently been published to monitor their occurrence in several foodstuffs. According to legislation, the analytical methodologies developed for their determination must include multiresidue extractions with high selectivity and sensitivity, as a set of 21 + 14 PAs should be simultaneously monitored. However, the multiresidue extraction of these alkaloids is a difficult task due to the high complexity of food and feed samples. Accordingly, although solid-phase extraction is still the technique most widely used for sample preparation, the QuEChERS method can be a suitable alternative for the simultaneous determination of multiple analytes, providing green extraction and clean-up of samples in a quick and cost-effective way. Hence, this review proposes an overview about the QuEChERS concept and its evolution through different modifications that have broadened its applicability over time, focusing mainly on its application regarding the determination of PAs in food and feed, including the revision of published works within the last 11 years.
Bi-functionalized mesostructured silicas as reversed-phase/strong anion-exchange sorbents. Application to extraction of polyphenols prior to their quantitation by UHPLC with ion-trap mass spectrometry detection
(SpringerLink, 2019-02-06) Casado, Natalia; Pérez-Quintanilla, Damián; Morante-Zarcero, Sonia; Sierra, Isabel
Hybrid mesostructured silicas with wormhole-like pore structure were synthesized and bi-functionalized with n-octyl (C8) and quaternary ammonium (NR4+) groups to obtain new sorbent materials for dispersive solid-phase extraction (dSPE) of polyphenols. Due to their nature of being both a reversed-phase and a strong anion-exchanger, the materials display mixed mode retention mechanism. During the synthesis, the functionalization conditions were varied to obtain materials with different functionalization degree. The resulting materials (denoted as HMS-RPC8-SAX-1, HMS-RPC8-SAX-2 and HMS-RPC8-SAX-3) show high surface area, wormhole-like framework and controlled pore size. They were evaluated for multicomponent extraction of 22 polyphenols, including phenolic acids, flavonoids and stilbenes, from spiked juice samples. The sample extracts were analyzed by ultra-high performance liquid chromatography coupled to ion-trap tandem mass spectrometry. The adsorption capability, the amount of sorbent, the eluent and the elution volume were optimized. Best performance was achieved by using HMS-RPC8-SAX-2, which is the material with the highest fraction of NR4+ groups. This material has a large extraction capability and provides high recovery values of the target analytes (70–101%) as a result of its hydrophobic and anion-exchange interactions. The detection limits for polyphenols in juice range from 1 to 560 ng mL−1.
Chiral Monolithic Silica-Based HPLC Columns for Enantiomeric Separation and Determination: Functionalization of Chiral Selector and Recognition of Selector-Selectand Interaction
(MDPI, 2021-08-29) Asmari, Mufarreh; Wang, Xiaoyu; Casado, Natalia; Piponski, Marjan; Kovalenko, Sergiy; Logoyda, Liliya; Hanafi, Rasha Sayed; El Deeb, Sami
This review draws attention to the use of chiral monolithic silica HPLC columns for the enantiomeric separation and determination of chiral compounds. Properties and advantages of monolithic silica HPLC columns are also highlighted in comparison to conventional particle-packed, fused-core, and sub-2- m HPLC columns. Nano-LC capillary monolithic silica columns as well as polymeric-based and hybrid-based monolithic columns are also demonstrated to show good enantioresolution abilities. Methods for introducing the chiral selector into the monolithic silica column in the form of mobile phase additive, by encapsulation and surface coating, or by covalent functionalization are described. The application of molecular modeling methods to elucidate the selector–selectand interaction is discussed. An application for enantiomeric impurity determination is also considered.
Comparison of high-throughput microextraction techniques, MEPS and -SPEed, for the determination of polyphenols in baby food by ultrahigh pressure liquid chromatography
(Elsevier, 2019-04-10) Casado, Natalia; Perestrelo, Rosa; L. Silva, Catarina; Sierra, Isabel; S. Câmara, José
In this study, two different high-throughput microextraction techniques, microextraction by packed sorbents (MEPS) and micro solid phase extraction (μ-SPEed®), were evaluated and compared, regarding the performance criteria, for the isolation of polyphenols from baby foods prior to their determination by ultrahigh pressure liquid chromatography (UHPLC). To achieve the best performance, influential parameters affecting extraction efficiency (including type of sorbent, number of extraction cycles, pH, elution solvent and elution volume) were systematically studied and optimized. To enable an effective comparison, selectivity, linear dynamic range, method detection (LODs) and quantification limits (LOQs), accuracy, precision and extraction yields, were determined and discussed for both techniques. Both methods provided the analytical selectivity required for the analysis of polyphenols in baby foods. However, μ-SPEed® sample treatment in combination with UHPLC-PDA has demonstrated to be more sensitive, selective and efficient than MEPS. Appropriate linearity in solvent and matrix-based calibrations, very low LODs and LOQs, ranging between 1.37 and 13.57 μg kg−1 and 4.57 – 45.23 μg kg−1, respectively, suitable recoveries (from 67 to 97%) and precision (RSD values < 5%) were achieved for the selected analytes by μ-SPEed®/UHPLC-PDA. Finally, the validated methodologies were applied to different commercial baby foods. Gallic acid, chlorogenic acid, epicatechin, ferulic acid, rutin, naringenin and myricetin are the most dominant polyphenols present in the studied baby food samples. The proposed methodology revealed a promising approach to evaluate the nutritional quality of this kind of products.
Current development and applications of ordered mesoporous silicas and other sol-gel silica-based materials in food sample preparation for xenobiotics analysis
(Elsevier, 2017) Casado, Natalia; Pérez-Quintanilla, Damián; Morante-Zarcero, Sonia; Sierra, Isabel
In the last years, sample preparation has been playing an important role in the analysis of xenobiotics in complex matrices, such as food samples. Recent advances in the development of new materials, such as ordered mesoporous silicas (OMSs) and other sol-gel silica-based materials, have gained increasing research interest in sample preparation and analytical chemistry due to their desirable characteristics and advantages versus traditional and commercial sorbents, since they enhance the analytical performance of many existing techniques or allow new ones to be developed. The aim of this review is to provide an overview with the most relevant achievements in the preparation and functionalization of OMSs and other sol-gel organic-inorganic hybrid silicas, and to give some recent examples from the last six years (from 2010 to 2016) regarding the analytical applications of these materials in sample preparation and extraction of xenobiotics from food products, including beverages and drinking water samples.
Development of Gluten-Free Bread Based on Maize and Buckwheat and Enriched with Aromatic Herbs and Spices
(MDPI, 2024-04-16) Ruiz-Aceituno, Laura; Casado, Natalia; Arriero-Romo, Emma; Morante-Zarcero, Sonia; Lázaro, Almudena; Sierra, Isabel
This work aimed to develop high-quality gluten-free bread based on maize and buckwheat with good palatability and texture properties. Different aromatic herbs and spices were incorporated as ingredients to evaluate whether their addition could influence the acceptability of consumers by improving the sensory properties of the final product. The bread formulation was first optimized through a response surface methodology. Accordingly, high specific volume, high springiness, and low hardness provided the best theoretical bread quality. However, when developing the product, some sensory defects were detected. Therefore, the addition of other ingredients (e.g., oil, sugar, and yeast) was tested. Finally, five different gluten-free bread with different combinations of aromatic herbs and spices were obtained. They were nutritionally characterized and subjected to sensory analysis by a panel of 140 consumers. The chemical composition of all bread was very similar, with only slight differences among them. Likewise, all of them received acceptable sensory scores (>5) from consumers, and some combinations of herbs and spices obtained scores higher than in the control bread (without herbs and spices). Overall, the gluten-free bread formulated with the combination of basil and oregano was the one that consumers significantly liked the most.
Dispersive solid-phase extraction of polyphenols from juice and smoothie samples using hybrid mesostructured silica followed by ultra-high-performance liquid chromatography-ion-trap tandem mass spectrometry
(ACS publications, 2018-12-20) Casado, Natalia; Morante-Zarcero, Sonia; Perez-Quintanilla, Damián; S. Câmara, José; Sierra, Isabel
A wormhole-like mesostructured silica was synthesized and modified with octadecylsilane (C18) groups. The resulting hybrid material (HMS-C18) was characterized and evaluated as sorbent for simultaneous extraction of 20 polyphenols from mixed fruit-vegetables juices and smoothies by dispersive solid-phase extraction (dSPE). The samples were first subjected to solvent extraction followed by dSPE procedure. The extraction step was optimized and combined with a reversed-phase ultra-high-performance liquid chromatography method coupled to ion-trap tandem mass spectrometry (UHPLC-IT-MS/MS), which was also optimized. HMS-C18 showed high potential to extract and purify the target analytes, being more effective than commercial C18 amorphous silica. The proposed method was validated for both samples, obtaining average recoveries from 57-99% with relative standard deviations lower than 9%. Its applicability in the analysis of commercial mixed fruit-vegetables juices and smoothies revealed mainly contents of rutin, 4-hydroxybenzoic acid, chlorogenic acid, epicatechin, caffeic acid and naringin in the samples analyzed
Editorial: Food bioactives: Cutting-edge methodologies for extraction and characterization
(Frontiers, 2022-12-09) M. Pereira, Jorge A.; Casado, Natalia; S. Câmara, José
Editorial on the Research Topic Food bioactives: Cutting-edge methodologies for extraction and characterization
Evaluation of bi-functionalized mesoporous silicas as reversed phase/cation-exchange mixed-mode sorbents for multi-residue solid phase extraction of veterinary drug residues in meat samples
(Elsevier, 2017) Sierra, Isabel; Casado, Natalia; Pérez-Quintanilla, Damián; Morante-Zarcero, Sonia
A SBA-15 type mesoporous silica was synthesized and bi-functionalized with octadecylsilane (C18) or octylsilane (C8), and sulfonic acid (SO3-) groups in order to obtain materials with reversed-phase/strong cation-exchange mixed-mode retention mechanism. The resulting hybrid materials (SBA-15-C18-SO3- and SBA-15-C8-SO3-) were comprehensively characterized. They showed high surface area, high pore volume and controlled porous size. Elemental analysis of the materials revealed differences in the amount of C18 and C8. SBA-15-C18-SO3- contained 0.19 mmol/g of C18, while SBA-15-C8-SO3- presented 0.54 mmol/g of C8. The SO3- groups anchored to the silica surface of the pore walls were 0.20 and 0.09 mmol/g, respectively. The bi-functionalized materials were evaluated as SPE sorbents for the multi-residue extraction of 26 veterinary drug residues in meat samples using ultra-high-performance liquid chromatography coupled to mass spectrometry detector (UHPLC-MS/MS). Different sorbent amounts (100 and 200 mg) and organic solvents were tested to optimize the extraction procedure. Both silicas showed big extraction potential and were successful in the extraction of the target analytes. The mixed-mode retention mechanism was confirmed by comparing both silicas with SBA-15 mesoporous silica mono-functionalized with C18 and C8. Best results were achieved with 200 mg of SBA-15-C18-SO3- obtaining recoveries higher than 70% for the majority of analytes.
Evaluation of mesostructured silica materials with diferent structures and morphologies as carriers for quercetin and naringin encapsulation
(Springer, 2021) Morante‑Zarcero, Sonia; Endrino, Alba; Casado, Natalia; Pérez‑Quintanilla, Damián; Sierra, Isabel
Two mesostructured silicas with wormhole-like pore arrangement (HMS and MSU-2) were synthesized and evaluated for the frst time as carriers for the encapsulation of two bioactive favonoids (quercetin and naringin). For comparative purposes, a hexagonal mesostructured SBA-15 silica type frequently used as encapsulating support was also prepared and tested. All the materials were characterized before and after the loading with the analytes. Diferent silica/analyte ratios were evaluated to determine the loading and encapsulation kinetics of the diferent materials. Both favonoids were successfully loaded inside the pores of the three silicas. The quercetin loading capacity of HMS was higher than SBA-15 and MSU-2 silicas, whereas for naringin SBA-15 and MSU-2 were slightly more efective. These diferences could be attributed to the molecular size of the analytes and the textural properties of the diferent materials. Nevertheless, HMS was the silica that enabled to release the highest amount of both analytes. Thus, it could be considered a suitable carrier of these favonoids and an alternative to other materials such as SBA-15. Moreover, the release process was performed under controlled conditions (pH 2.0 and 7.4) to simulate digestive conditions. Quercetin was delivered faster and more efciently from the encapsulated at pH 2.0, whereas no diferences were observed for naringin at both pHs. Finally, the antioxidant activity of the resulting encapsulates was determined. The results obtained suggested the potential use of wormhole-like mesostructured silicas as carriers to enhance the stability and bioavailability of favonoids, so they can be used in future food and biomedical applications.
Evaluation of mesostructured silicas with wormhole-like framework functionalized with hydrophobic groups as alternative sorbents for extraction of drug residues from food samples
(Elsevier, 2018-06) Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel
Different mesostructured silicas were synthesized and functionalized with octadecylsilane groups under same conditions. All materials were characterized and evaluated as sorbents for simultaneous multi-residue extraction of veterinary drugs from bovine meat samples by solid-phase extraction prior to their chromatographic analysis coupled to tandem mass spectrometry. The results obtained were compared to select the material with the highest extraction potential to achieve this purpose.
Evaluation of the thermal stability and transfer rate of pyrrolizidine alkaloids during the brewing of herbal infusions contaminated with Echium vulgare and Senecio vulgaris weeds
(Elsevier, 2023) Fernández-Pintor, Begoña; Casado, Natalia; Morante-Zarcero, Sonia; Sierra, Isabel
Pyrrolizidine alkaloids (PAs) are currently in the spotlight of food safety due to the potential health risk that their intake may entail for consumers. Among the wide variety of food products likely to be contaminated with PAs, teas and herbal teas stand out because of their cross-contamination with weeds from PA-producing plants. Accordingly, this work simulates the cross-contamination of chamomile tea samples with weeds of Senecio vulgaris and Echium vulgare to evaluate the effect of brewing on the PA content at different temperature (100 and 75 ◦C) and time (5 and 10 min) conditions. The results of the thermal degradation study revealed PAs are quite stable compounds under the conditions assayed, being the initial PA concentration the variable that strongly affected the thermal stability of these compounds, rather than the brewing temperature and time. On the other hand, it was confirmed that not all PAs are effectively transferred from the dry material to the infusion during the brewing process, leading to overall transfer rates between 13 ± 1 to 87 ± 10%. Also, it was observed that the extraction efficiency may be influenced by the type of matrix, since transfer rates were lower when the PA migration came from Echium vulgare than from Senecio vulgaris. Moreover, it was confirmed that the real content of PAs in a cup of tea can be overestimated in 2–7 times if their transfer rate is not considered during the brewing process, highlighting the importance of analyzing the infusion samples instead of the dry tea samples to correctly assess the risk exposure of consumers to these contaminants.
Improving the food safety of bakery products by simultaneously monitoring the occurrence of pyrrolizidine, tropane and opium alkaloids
(Elsevier, 2024-08-05) Vera-Baquero, Fernando L.; Casado, Natalia; Morante-Zarcero, Sonia; Sierra, Isabel
The exponential number of food alerts about concerning levels of some plant-alkaloids, such as pyrrolizidine, tropane and opium alkaloids, have stressed the need to monitor their occurrence in foods to avoid toxic health effects derived from their intake. Therefore, analytical strategies to simultaneously monitor the occurrence of these alkaloids should be developed to ensure food safety an comply with regulations. Accordingly, this work proposes an efficient multicomponent analytical strategy for the simultaneous extraction of these alkaloids from commercial bakery products. The analytical method was validated and applied to the analysis of 15 samples, revealing that 100% of them contained at least one of the target alkaloids, in some cases exceeding the maximum limits legislated. Moreover, in two samples the 3 different alkaloid families were detected. These results confirm the importance of simultaneously monitoring these alkaloids in food and highlight also considering some opium alkaloids in current legislation
Insight into the Impact of Food Processing and Culinary Preparations on the Stability and Content of Plant Alkaloids Considered as Natural Food Contaminants
(MDPI, 2023-01-29) Casado, Natalia; Casado-Hidalgo, Gema; González-Gómez, Lorena; Morante-Zarcero, Sonia; Sierra, Isabel
Pyrrolizidine alkaloids, tropane alkaloids and opium alkaloids are natural plant toxins that have recently gained special interest in food safety due to their concerning occurrence in many foods and feeds. Although a legislation for these alkaloids has recently been established, the concentration levels of these toxins in food exceed in many cases the maximum limit established by the competent authorities. Moreover, these regulations only establish maximum limits of these compounds for certain raw materials, but processed products are generally not considered. However, it is important to correctly assess the potential health risk of these alkaloids through the diet. Accordingly, this review aims to provide insight into these alkaloids and give an overview on how food processing and culinary preparation can influence their content and stability. For this purpose, the most relevant works that address the effect of heat treatment, fermentation, infusion preparation (transfer rate) and other treatments (milling, washing and soaking) on these natural toxins are reviewed. To date, this research field has been scarcely studied and many of the results published are contradictory, so it is not always possible to establish conclusive findings. In many cases, this is due to a lack of experimental design and exhaustive control of the different variables that may affect these treatments and preparations. Likewise, considering the transformation of these alkaloids into toxic degradation products it is also of high interest. Therefore, further studies are needed to delve deeper into the stability of these toxins and to understand how their content may be affected by the transformation of contaminated raw materials into processed products, so that the risk exposure of the population to these alkaloids through diet can be determined more precisely. Hence, this topic constitutes a research line of great interest for future works with many challenges to be resolved.
Miniaturized Analytical Strategy Based on μ‑SPEed for Monitoring the Occurrence of Pyrrolizidine and Tropane Alkaloids in Honey
(American Chemical Society, 2023-12-18) Casado, Natalia; Morante-Zarcero, Sonia; Sierra, Isabel
Currently, the analysis of trace-level contaminants in food must be addressed following the Green Analytical Chemistry principles and with the commitment to the Sustainable Development Goals. Accordingly, a sustainable and ecofriendly microextraction procedure based on µ-SPEed® followed by ultra-high liquid chromatography coupled to ion-trap tandem mass spectrometry analysis was developed to determine the occurrence of pyrrolizidine and tropane alkaloids in honey samples. The µ-SPEed® procedure took approximately 3 min per sample, using only 100 μL of organic solvent and 300 μL of diluted sample. The method was properly validated (overall recoveries 72-100% and precision RSD values ≤15%) and its greenness was scored at 0.61 out of 1. The method was applied to different honey samples, showing overall contamination levels from 32 to 177 µg/kg of these alkaloids. Atropine was found in all the samples, whereas retrorsine N-oxide, lasiocarpine, echimidine and echimidine N-oxide were the main pyrrolizidine alkaloids in the samples analyzed.
Miniaturized and modified QuEChERS method with mesostructured silica as clean-up sorbent for pyrrolizidine alkaloids determination in aromatic herbs
(Elsevier, 2022-06) Izcara, Sergio; Casado, Natalia; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; Sierra, Isabel
This work proposes the miniaturization and modification of the QuEChERS strategy using different large pore mesostructured silicas, non-modified and modified with amino groups (NH2), as dispersive clean-up sorbents for multi-component extraction of 21 pyrrolizidine alkaloids from different aromatic herbs, combined with ultra-high performance liquid chromatography coupled to tandem mass spectrometry analysis. The procedure was miniaturized by reducing the amounts of sample (0.2 g), solvents (2 mL), clean-up sorbents (25 mg sorbent + 150 mg MgSO4) and partitioning salts (0.65 g) employed. Best results were achieved using mesostructured silicas (LP-MS-NH2) than conventional PSA. The method was validated (overall recoveries 73–105%) and applied to the analysis of 17 samples. All the samples were contaminated with PAs (average concentration 262 µg/Kg). Thyme and basil samples were the most contaminated, whereas rosemary was the least. Lasiocarpine, senecivernine N-oxide and europine N-oxide were the main PAs that contributed to their contamination.
New Advanced Materials and Sorbent-Based Microextraction Techniques as Strategies in Sample Preparation to Improve the Determination of Natural Toxins in Food Samples
(MDPI, 2020) Casado, Natalia; Gañán, Judith; Morante-Zarcero, Sonia; Sierra, Isabel
Natural toxins are chemical substances that are not toxic to the organisms that produce them, but which can be a potential risk to human health when ingested through food. Thus, it is of high interest to develop advanced analytical methodologies to control the occurrence of these compounds in food products. However, the analysis of food samples is a challenging task because of the high complexity of these matrices, which hinders the extraction and detection of the analytes. Therefore, sample preparation is a crucial step in food analysis to achieve adequate isolation and/or preconcentration of analytes and provide suitable clean-up of matrix interferences prior to instrumental analysis. Current trends in sample preparation involve moving towards “greener” approaches by scaling down analytical operations, miniaturizing the instruments and integrating new advanced materials as sorbents. The combination of these new materials with sorbent-based microextraction technologies enables the development of high-throughput sample preparation methods, which improve conventional extraction and clean-up procedures. This review gives an overview of the most relevant analytical strategies employed for sorbent-based microextraction of natural toxins of exogenous origin from food, as well as the improvements achieved in food sample preparation by the integration of new advanced materials as sorbents in these microextraction techniques, giving some relevant examples from the last ten years. Challenges and expected future trends are also discussed.