Environmental chiral analysis of beta-blockers: evaluation of different n-alkyl-modified SBA-15 mesoporous silicas as sorbents in solid-phase extraction

The extraction and preconcentration of chiral beta-blockers in environmental water was evaluated by solidphase extraction (SPE) employing an SBA-15 ordered mesoporous silica functionalised with alkyl chains of different length. The materials were characterised by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption isotherm measurements and elemental analysis. Important parameters influencing extraction efficiency, including the type and amount of sorbent and the breakthrough volume, were optimised. The results obtained showed that the organic chain length played an important role in the behaviour of these sorbents. Under optimised conditions, using 200 mg SBA-15-C8 as sorbent, a simple analytical method based on off-line SPE coupled to chiral capillary electrophoresis with diode array detection (SPE-chiral CE-DAD) was developed. Method detection and quantification limits were lower than 0.6 and 1.9 mu g L-1 respectively for all enantiomers, with a preconcentration factor of 500-fold. The method was successfully applied to the chiral analysis of atenolol, metoprolol, pindolol and propranolol in river and sewage water samples. Satisfactory recoveries (between 86 +/- 2 and 98 +/- 1 %) and repeatability (relative standard deviation (RSD) < 9 %, n = 3) were obtained. Metoprolol was detected in sewage water at a concentration of 10.7 and 9.9 mu g L-1 and an enantiomeric fraction of 0.52 and 0.48 for the first- and the second-migrating enantiomers respectively. These results emphasise the importance of enantioselective analysis for environmental risk assessment

One-pot synthesized functionalized mesoporous silica as a reversed-phase sorbent for solid-phase extraction of endocrine disrupting compounds in milks

A new procedure for the determination of 12 naturally occurring hormones and some related synthetic chemicals in milk, commonly used as growth promoters in cattle, is reported. The method is based on liquid–liquid extraction followed by solid-phase extraction (SPE) using a new one-pot synthesized ordered mesoporous silica (of the SBA-15 type) functionalized with octadecyl groups (denoted as SBA-15-C18-CO) as reversed-phase sorbent. The analytes were eluted with methanol and then submitted to HPLC with diode array detection. Under optimal conditions, the method quantification limit for the analytes ranged from 0.023 to 1.36 μg/mL. The sorbent affored the extraction of estrone, 17β-estradiol, estriol, progesterone, hexestrol, diethylstilbestrol, 4-androstene-3,17-dione, ethinylestradiol, 17α-methyltestosterone, nandrolone, prednisolone and testosterone with mean recoveries ranging from 72% to 105% (except for diethylstilbestrol) with RSD < 11%. These results were comparable and, in some cases, even better than those obtained with other extraction methods, therefore SBA-15-C18-CO mesoporous silica possess a high potential as a reversed-phase sorbent for SPE of the 12 mentioned endocrine disrupting compounds in milk samples

Ordered mesoporous silica functionalized with beta-cyclodextrin derivative for stereoisomer separation of flavanones and flavanone glycosides by nano-liquid chromatography and capillary electrochromatography

In this paper a chiral stationary phase (CSP) was prepared by the immobilization of a beta-CD derivative (3,5-dimethylphenylcarbamoylated beta-CD) onto the surface of amino-functionalized spherical ordered mesoporous silica (denoted as SM) via a urea linkage using the Staudinger reaction. The CSP was packed into fused silica capillaries 100 mu m I.D. and evaluated by means of nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) using model compounds for the enantio- and the diastereomeric separation. The compounds flavanone, 2'-hydroxyflavanone, 4'-hydroxyflavanone, 6hydroxyflavanone, 4'-methoxyflavanone, 7-methoxyfiavanone, hesperetin, hesperidin, naringenin, and naringin were studied using reversed and polar organic elution modes. Baseline stereoisomer resolution and good results in terms of peak efficiency and short analysis time of all studied flavonoids and flavanones glycosides were achieved in reversed phase mode, using as mobile phase a mixture of MeOH/H2O, 10 mM ammonium acetate pH 4.5 at different ratios. For the polar organic mode using 100% of MeOH as mobile phase, the CSP showed better performances and the baseline chiral separation of several studied compounds occurred in an analysis time of less than 10 min. Good results were also achieved by CEC employing two different mobile phases. The use of MeOH/H2O, 5 mM ammonium acetate buffer pH 6.0 (90/10, v/v) was very effective for the chiral resolution of flavanone and its methoxy and hydroxy derivatives. (C) 2017 Elsevier B.V. All rights reserved

Development of a digital mission diary based on overcoming different challenges to improve the academic performance of students in the degree of Food Science and Technology

[EN] This work describes the implementation of a teaching innovation activity based on gamification within the degree in Food Science and Technology at the Rey Juan Carlos University during the 2022-2023 academic year. The activity was carried out voluntarily in the subject of Analysis and Control of Food Quality in the 3rd year to get an extra score in the final grade. The main objective was to encourage the study, motivation and autonomous work of the students. Accordingly, the activity involved the development of a digital mission diary by each student based on overcoming a set of challenges related to the solid phase extraction technique used in food analysis field. These challenges were part of a training itinerary with different levels that the students had to overcome week by week. The results obtained show an improvement in the academic performance of the participating students, who, by carrying out the activity, have also developed general and specific skills useful to improve their understanding of other degree subjects and to address their Final Degree Project.[ES] Este trabajo describe la implantación de una actividad de innovación docente basada en la metodología activa de la gamificación dentro del grado en Ciencia y Tecnología de los Alimentos de la Universidad Rey Juan Carlos durante el curso académico 2022-2023. La actividad se realizó en la asignatura de Análisis y Control de la Calidad de los Alimentos de 3º curso de forma voluntaria para conseguir una puntuación extra en la calificación final. El principal objetivo fue incentivar el estudio, la motivación y el trabajo autónomo de los estudiantes. Para ello, la actividad consistió en la creación de un diario de misión digital por parte de cada estudiante basado en la superación de un conjunto de retos relacionados con la técnica de extracción en fase sólida en el análisis de alimentos. Estos retos formaban parte de un itinerario formativo con distintos niveles que debían ir superando semana a semana. Los resultados obtenidos demuestran una mejora del rendimiento académico de los estudiantes participantes, los cuales al realizar la actividad también han desarrollado competencias generales y específicas útiles para mejorar la compresión de otras asignaturas del grado y para abordar su Trabajo Fin de Grado.Escuela Superior de Ciencias Experimentales y Tecnología de la Universidad Rey Juan Carlos a través de la Ayuda concedida en la Convocatoria para la distribución de presupuestos de 2023 destinados a Actividades de Innovación Docente en la ESCETCasado, N.; Gañán, J.; González Gómez, L.; Casado Hidalgo, G.; Morante Zarcero, S.; Sierra, I. (2023). Creación de un diario de misión digital basado en la superación de distintos retos para mejorar el rendimiento académico de los estudiantes del grado en Ciencia y Tecnología de los Alimentos. Editorial Universitat Politècnica de València. 626-640. https://doi.org/10.4995/INRED2023.2023.1656062664

Influence of the electrografting method on the performances of a flow electrochemical sensor using modified electrodes for trace analysis of copper (II).

International audienceThe performances of carboxylate- and cyclam-modified graphite felt electrodes prepd. by different electrografting methods for trace anal. of copper (II) were compared to det. the influence of the immobilization process of the linkers on the sensor properties. The derivatization performed by cathodic redn. of diazonium salts and by anodic oxidn. of amines in org. and aq. media was first evaluated by cyclic voltammetry and XPS analyses, showing a higher surface coverage for the redn. process. Cyclam was subsequently attached on the COOH-modified graphite felts by a coupling reaction. The modified electrodes were then employed in a flow anal. system for trace anal. of copper (II) ions. The influence of the surface coverage and the nature of the linker on the electrochem. signal obtained by linear sweep stripping voltammetry anal. after a preconcn. step performed at open circuit was highlighted. The selectivity estd. in the presence of lead used as a common ion interferent was higher when a selective receptor was used and depends on the nature of the linker. [on SciFinder(R)

Molecular Modeling Study of Chiral Separation and Recognition Mechanism of β-Adrenergic Antagonists by Capillary Electrophoresis

Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the –OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy

A Miniaturized QuEChERS Method Combined with Ultrahigh Liquid Chromatography Coupled to Tandem Mass Spectrometry for the Analysis of Pyrrolizidine Alkaloids in Oregano Samples

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 foodstuff. Accordingly, this work presents the development of a miniaturized strategy based on the QuEChERS (quick, easy, cheap, effective, 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 &lt;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 &micro;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 &micro;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

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

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

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

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