showing 14 related works from this author
Simultaneous determination of third-generation synthetic cannabinoids in oral fluids using cyclodextrin-silica porous sorbents
2022
Abstract A microporous material made of cyclodextrin units covalently immobilized into a silica network has found an innovative bioanalytical application in the sample clean-up and simultaneous isolation of three synthetic cannabinoids (ADB-CHMICA, MMB-CHMICA, and MDMB-CHMCZCA) from human oral fluid through solid-phase extraction. The subsequent quantitation is carried out using liquid chromatography coupled to fluorescence detection. The optimized experimental procedure gives recoveries ranging from 76% to 96% in oral fluid samples spiked with the studied cannabinoids at the µg L-1 level. High selectivity is obtained through the extraction procedure due to the presence of cyclodextrin in t…
Bimodal porous silica nanomaterials as sorbents for an efficient and inexpensive determination of aflatoxin M1 in milk and dairy products
2020
Abstract An extraction procedure was developed for the determination of aflatoxin M1 in milk and dairy products. A sorbent based on UVM-7 mesoporous silica was used as solid phase for the sample clean-up, and the analyte determination was carried out by HPLC coupled to a fluorescence detector. The material architecture was characterized by transmission electronic microscopy, X-ray diffraction, 29Si NMR and nitrogen adsorption-desorption. After the optimization of extraction parameters, the influence of the matrix has been evaluated, obtaining recoveries in the range 78–105% for whole and skimmed milk and yogurt matrix. The reusability of the material was also proved. The sensitivity of the …
Host-guest interactions for extracting antibiotics with a γ-cyclodextrin poly(glycidyl-co-ethylene dimethacrylate) hybrid sorbent
2021
Abstract A procedure for the solid-phase extraction of antibiotics (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and sparfloxacin) in water has been developed. The sorbent used is based on a poly(glycidyl-co-ethylene dimethacrylate) network, whose previously modified surface has been functionalized with γ-cyclodextrin through a click-chemistry reaction. The architecture of the material has been characterized by thermogravimetric analysis, N2 adsorption-desorption, Raman spectroscopy, confocal microscopy, and scanning electron microscopy, showing good capability to be used as a filler for extraction cartridges. The optimization of the extraction methodology shows good intra-day and inter…
Cyclodextrins as a Key Piece in Nanostructured Materials: Quantitation and Remediation of Pollutants
2021
Separation and pre-concentration of trace pollutants from their matrix by reversible formation of inclusion complexes has turned into a widely studied field, especially for the benefits provided to different areas. Cyclodextrins are non-toxic oligosaccharides that are well known for their host–guest chemistry, low prices, and negligible environmental impact. Therefore, they have been widely used as chiral selectors and delivery systems in the pharmaceutical and food industry over time. However, their use for extraction purposes is hampered by their high solubility in water. This difficulty is being overcome with a variety of investigations in materials science. The setting-up of novel solid…
Enhancing extraction performance of organophosphorus flame retardants in water samples using titanium hierarchical porous silica materials as sorbent…
2021
Abstract A sorbent for the extraction of organophosphorus flame retardants has been proposed, based on UVM-7 (University of Valencia Materials) mesoporous silica doped with titanium. Designed cartridges have been applied to the extraction and preconcentration of flame retardants in water samples, followed by gas chromatography coupled to a mass spectrometry detector. Firstly, UVM-7 materials with different contents of titanium were synthesized and characterized by several techniques, thus confirming the proper mesoporous architecture. The potential of these materials was assessed in comparison with their morphological properties, resulting Ti50-UVM-7 the best solid phase. Several extraction…
A new proposal for the determination of polychlorinated biphenyls in environmental water by using host-guest adsorption
2020
Abstract Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants whose wide industrial use has been banned over the years in most countries due to their persistence and bioaccumulation. In fact, the International Agency for Research on Cancer defined them in 2016 as carcinogenic to humans based on sufficient evidence of an increased risk of cancer, being children and pregnant or lactating women the most vulnerable population subgroups. In this work, a new alternative for the determination of polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180) in water samples has been developed by using a cyclodextrin-containing silica microparticulated material as …
A city-level analysis of air pollution, climate and COVID-19 early spread during the Spanish lockdown
2020
AbstractThe COVID-19 outbreak has escalated into the worse pandemic of the present century. The fast spread of the new SARS-CoV-2 coronavirus has caused devastating health and economic crises all over the world, with Spain being one of the worst affected countries in terms of confirmed COVID-19 cases and deaths per inhabitant. In this situation, the Spanish Government declared the lockdown of the country. The variations of air pollution in terms of fine particulate matter (PM2.5) levels in seven cities of Spain are analyzed here considering the effect of meteorology during the national lockdown. The possible associations of PM2.5pollution and climate with COVID-19 accumulated cases were als…
Do Social Chemophobic Attitudes Influence the Opinions of Secondary School Students?
2021
For some time now, chemistry has not had a good reputation in society. The population identifies this discipline with industries and pollution, while its positive contributions are usually ignored. This fear of chemistry may affect the opinion of society toward not only science, but also the scientific work itself. To assess the prevalence of this social phenomenon among them, a group of 351 preuniversity students was surveyed and the answers provided were analyzed based on their characteristics (age, sex, and location). The results support the usefulness of the developed questionnaire and show that there already exists a tendency to reject everything “containing chemicals” or that “is not …
Comparison of the solid-phase extraction efficiency of a bounded and an included cyclodextrin-silica microporous composite for polycyclic aromatic hy…
2016
Solid-phase extraction is one of the most important techniques for sample purification and concentration. A wide variety of solid phases have been used for sample preparation over time. In this work, the efficiency of a new kind of solid-phase extraction adsorbent, which is a microporous material made from modified cyclodextrin bounded to a silica network, is evaluated through an analytical method which combines solid-phase extraction with high-performance liquid chromatography to determine polycyclic aromatic hydrocarbons in water samples. Several parameters that affected the analytes recovery, such as the amount of solid phase, the nature and volume of the eluent or the sample volume and …
Comparison of silica-based materials for organophosphorus pesticides sampling and occupational risk assessment.
2020
Abstract A novel air sampler has been designed containing a sorbent based on UVM-7 mesoporous silica doped with Ti. The sorbent has been applied for the determination of organophosphorus pesticides in occupational air, followed by gas chromatography with mass spectrometry detection. Thus, several silica materials with different structures (mesoporous UVM-7 and microporous xerogels) were synthesized, and modified with the addition of Ti and Fe. The structure of these materials was proved by transmission electronic microscopy, energy-dispersive X-ray, X-ray diffraction, nitrogen adsorption-desorption and UV–Vis and Raman spectroscopy. The potential of these materials for the retention of pest…
Changes in air pollution during COVID-19 lockdown in Spain: a multi-city study
2021
Highlights • Variations in air quality in terms of CO, SO2, PM10, O3 and NO2 levels were studied • The lockdown of Spain was not able to reduce severe air pollution in all its forms • Significant reductions of NO2 levels were achieved in most cities • Increases of O3 pollution levels were found in several cities
Design, characterization and comparison of materials based on β and γ cyclodextrin covalently connected to microporous silica for environmental analy…
2018
Abstract Determination of organic pollutants in environmental samples presents great difficulties due to the lack of sensitivity and selectivity in many of the existing analytical methods. In this work, the efficiency of materials based on silica structures containing bounded γ-cyclodextrin has been evaluated to determinate phenolic compounds and polycyclic aromatic hydrocarbons in air and water samples, respectively, in comparison with materials made of β-cyclodextrin. According to the results obtained for the material characterization, the new γ-cyclodextrin solid phase does not apparently present any porosity when used in air samples, but it has been shown to work efficiently for the pre…
Determination of phenolic compounds in air by using cyclodextrin-silica hybrid microporous composite samplers
2015
An analytical method for the determination of phenolic compounds in air samples based on the use of cyclodextrin-silica hybrid microporous composite samplers is proposed. The method allows the determination of phenol, guaiacol, cresol isomers, eugenol, 4-ethylphenol and 4-ethylguaiacol in workplaces according to the Norm UNE-EN 1076:2009 for active sampling. Therefore, the proposed method offers an alternative for the assessment of the occupational exposure to phenol and cresol isomers. The detection limits of the proposed method are lower than those for the NIOSH Method 2546. Storage time of samples almost reaches 44 days. Recovery values for phenol, guaiacol, o-cresol, m-cresol, p-cresol,…
Study of silica-structured materials as sorbents for organophosphorus pesticides determination in environmental water samples
2018
Abstract A novel sorbent based on a UVM-7 mesoporous silica doped with Ti has been synthesized and used for solid-phase extraction of several organophosphorus pesticides in environmental water samples followed by gas chromatography coupled to a nitrogen-phosphorus selective detector. Thus, mesoporous silica materials doped with Ti and Fe as well as immobilized cyclodextrin silica-based supports were prepared and morphologically characterized by several techniques such as transmission electronic microscopy, nitrogen adsorption-desorption and X-ray diffraction. These sorbents were comparatively evaluated, and Ti25-UVM-7 material was selected as the best solid phase. After optimization of extr…