A novel magnetic molecularly imprinted polymer for selective extraction and determination of quercetin in plant samples

Molecularly imprinted polymers that mimic the binding mechanism of antibodies and their antigens exhibit several advantages, such as fast synthesis, low cost, high stability, and allow to overcome the ethical issues associated with antibody farming in animals. Herein, a novel strategy combining the magnetic molecularly imprinted polymer (MMIP) as an artificial antibody with a fluorescence procedure for the detection of quercetin in plant samples was designed. The MMIP was synthesized via a radical polymerization process to recognize specific functional groups of quercetin using a green technique based on high energy ultrasound irradiation. The developed MMIP was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning/transmission electron microscopy, and thermal gravimetric analysis, which confirmed the successful preparation of MMIP. The adsorption capacity and selectivity of the MMIP for quercetin and other interferents analogous were performed. The MMIP was applied in the solid-phase extraction (SPE) technique as a selective sorbent for the sample preparation. Besides, a sensitive fluorometric method for the quantitation of quercetin was developed. A linear response was obtained within the concentration of 0.005e1.25 mg mL 1 of quercetin. The limit of detection and quantitation were 1.1 ng mL 1 and 3.7 ng mL 1, respectively. The average recoveries for quercetin were between 92.2% and 104.7% with an RSD less than 5.06% in spiked orange juice and tea extract samples. Furthermore, the developed procedure was successfully combined with a new paperbased analytical device for on-site smartphone analysis of quercetin. © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Rapid extraction and detection of ellagic acid in plant samples using a selective magnetic molecularly imprinted polymer coupled to a fluorescence method

A remarkable growth was noticed in the development of molecularly imprinted polymers (MIPs), which have used as efficient synthetic antibodies that contain selective cavities to the target molecule. Hereunder, a novel strategy using MIP as a sorbent in solid-phase extraction was coupled to a fluorescence method for ellagic acid (EA) purification and immediate detection. The synthesis of magnetic-MIP (MMIP) using a rapid and green ultrasound technology was assessed by central composite design to determine the optimal polymerization conditions for a high-imprinting polymer. The MMIP was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and scanning/transmission electron microscopy, which accurately confirmed the functional, magnetic, and morphological features of MMIP. The prepared MMIP was demonstrated to be selective for EA compared to many similar phenols. The spectrofluorometric method showed a linear range from 0.05 to 2 μg·mL−1 of EA, and the limits of detection (LOD) and quantification (LOQ) were 0.005 and 0.02 μg·mL−1, respectively. Besides, the novel proposed smartphone method using the ultraviolet lamp as the excitation source presented a linear range from 0.2 to 4 μg·mL−1, a LOQ of 0.2 μg·mL−1, and a LOD of 0.07 μg.mL−1. The proposed strategy revealed high efficiency in the extraction and detection of EA in grape, redberry, and green tea. Effectively, the calculated recoveries were ranging from 80 to 102% with low values of relative standard deviation ([removed]10 página

In-Situ and Experimental Evidence for Acidic Weathering of Rocks and Soils on Mars

Experimental data for alteration of synthetic Martian basalts at pH=0-1 indicate that chemical fractionations at low pH are vastly different from those observed during terrestrial weathering. Rock analyses from Gusev crater are well described by the relationships apparent from low pH experimental alteration data. A model for rock surface alteration is developed which indicates that a leached alteration zone is present on rock surfaces at Gusev. This zone is not chemically fractionated to a large degree from the underlying rock interior, indicating that the rock surface alteration process has occurred at low fluid-to-rock ratio. The geochemistry of natural rock surfaces analyzed by APXS is consistent with a mixture between adhering soil/dust and the leached alteration zone. The chemistry of rock surfaces analyzed after brushing with the RAT is largely representative of the leached alteration zone. The chemistry of rock surfaces analyzed after grinding with the RAT is largely representative of the interior of the rock, relatively unaffected by the alteration process occurring at the rock surface. Elemental measurements from the Spirit, Opportunity, Pathfinder and Viking 1 landing sites indicate that soil chemistry from widely separated locations is consistent with the low-pH, low fluid to rock ratio alteration relationships developed for Gusev rocks. Soils are affected principally by mobility of FeO and MgO, consistent with alteration of olivine-bearing basalt and subsequent precipitation of FeO and MgO bearing secondary minerals as the primary control on soil geochemistry

Transformations de mesures de Gibbs

Nous considerons deux bases mesurables (, f, i, f) et ( *, f *, i *, f *) et une transformation (, ) f/f *-admissible. Nous montrons que si p est une mesure de gibbs associee a une f-specification = ( v) v e i satisfaisant la condition de dynkin (i.e. Les images des noyaux v, par , sont constantes sur les classes d'equivalence de ), alors sa mesure image p par est une mesure de gibbs associee a une f *-specification * obtenue a partir de par une transformation de renormalisation r , . En particulier, lorsque est gibbsienne (i.e. Definie a partir d'un f-hamiltonien h et d'une f-specification de reference o), nous donnons des conditions suffisantes, sur h et o, qui garantissent le resultat precedent. Nous developpons dans la suite plusieurs applications de ce resultat. Nous montrons d'abord, comment construire des mesures de gibbs sur l'espace quotient / et sur un domaine fondamental de la relation d'equivalence , a partir de mesures de gibbs sur . Nous en deduisons une construction de mesures de gibbs sur l'espace des orbites et sur un domaine fondamental d'un groupe . Nous nous interessons ensuite a une loi gibbsienne p d'une collection infinie de processus de markov (x i) i zd en interaction, et nous montrons que sa mesure image par une transformation de dynkin est la loi gibbsienne de la collection infinie de processus de markov y = (y i) i zd = ((x i) i zd) en interaction. Enfin, par transformation de systemes gradients stochastiques, nous obtenons des resultats sur l'existence des solutions, leur unicite et des informations concernant les lois initiales reversibles, pour les dynamiques images, comme l'equation interface de ginzburg-landau.LILLE1-BU (590092102) / SudocSudocFranceF

Paper-Based Analytical Device for One-Step Detection of Bisphenol-A Using Functionalized Chitosan

Bisphenol-A (BPA) is defined as one of the endocrine disrupting compounds. The accurate and inexpensive colorimetric paper-based analytical devices (PADs) are of crucial importance for BPA analysis. In this context, we developed for the first time a new PAD modified with chitosan and sulfamethoxazole (Chitosan-PAD) for the visual detection of BPA in water. The PAD was characterized by Fourier-transform infrared spectroscopy, which confirmed its modification by the functionalized chitosan. A yellow coloration was developed when a small volume of BPA was added to the Chitosan-PAD, allowing for visual and smartphone detection. This new strategy is based on a specific combination of BPA with chitosan and sulfamethoxazole that provides a hight selectivity to the Chitosan-PAD. The proposed PAD was successfully employed in combination with a pre-concentration step for the detection of 0.01 µg mL−1 of PBA with the naked eye using a 10-fold preconcentration factor. The PAD was effectively applied for BPA quantification in water samples with good recoveries. The developed PAD provides a green and cost-effective strategy for the on-site and one-step detection of BPA in water samples

Educació intercultural a través de la música i la dansa a l’Educació Primària: una proposta didàctica

[cat] La música té la capacitat de transmetre valors i emocions comunes a totes les cultures. Per aquest motiu, la música juntament amb la dansa formen l'eina idònia per a establir un diàleg intercultural. El present document, recull vuit propostes d'intervenció educativa, dirigides a complir el principal objectiu d'aquest treball; afavorir la convivència entre l'alumnat d'Educació Primària a través de la música i la dansa. La metodologia emprada en aquest treball consisteix a fer una cerca d'informació per establir un marc teòric en el qual posteriorment basarem l'elaboració de les nostres activitats didàctiques interculturals en l'àrea de música, dirigides a l'alumnat del segon cicle d'Educació Primària concretament al cinquè curs. Amb aquesta proposta d'intervenció, pretenem crear una eina d'utilitat per a la pràctica docent.[eng] Music has the capacity to transmit values and emotions common to all cultures . For this reason , music together with dance is the ideal tool to establish an intercultural dialogue . This document includes eight proposals for educational intervention , aimed at fulfilling the main objective of this work : to promote coexistence among primary school students through music and dance . The methodology u sed in this work consists of a search for information to establish a theoretical framework on which we will later b ase the development of our intercultural teaching activities in the area of music , aimed at students in the second cycle of primary education , specifically in the fifth year . With this proposal of intervention , we intend to create a u seful tool for teaching practice

Comparación de métodos de extracción de hidrocarburos policíclicos aromáticos (PAHs) de muestras aire (Filtros PM10)

[spa] La etapa del tratamiento de las muestras antes de ser analizadas es un paso crítico que tiene repercusión en los resultados. En la actualidad, uno de los métodos más utilizados para la extracción de hidrocarburos policíclicos aromáticos (PAHs) es la extracción mediante ultrasonidos con una mezcla de diclorometano-hexano. En este trabajo se plantea otro método de extracción asistida por microondas, también propuesto por la norma UNE-EN-15549 "Método normalizado para la medición de la concentración de benzo(a)pireno en el aire ambiente", que es menos tedioso y utiliza menos disolventes que la extracción asistida por ultrasonidos. Así, el objetivo de este trabajo es comparar ambos protocolos de extracción para los PAHs identificados como contaminantes prioritarios por la EPA, en términos de eficiencias de extracción y límites de detección (LOD) y de cuantificación (LOQ). Para la cuantificación de los PAHs se utilizó la técnica cromatográfica HPLC con detección por fluorescencia. El protocolo de extracción asitida por microondas (EAM) incluye una reducción del volumen con la ayuda de un rotavapor, hasta sequedad. Posteriormente, se reconstituye el residuo seco con hexano y se pasa por una columna de fraccionamiento para eliminar los compuestos alifáticos presentes en la muestra. Finalmente, se vuelve a llevar a sequedad y se reconstituye con acetonitrilo. Los resultados de la EAM mostraron rendimientos de extracción aceptables (entre 50 y 101%). Además, es una metodología menos tediosa que el método con extracción por ultrasonidos y presenta LODs y LOQs en su gran mayoría, más bajos. Se puede afirmar que la EAM es más conveniente, con un menor tiempo de análisis, límites de detección más bajos, y reduce la cantidad de disolventes, siendo más amigable con el medio ambiente.[eng] The sample pre-treatment is a critical step that has an impact on the results. At present, one of the most widely used methods for the extraction of polycyclic aromatic hydrocarbons (PAHs) is extraction by means of ultrasound with a dichloromethane-hexane mixture. In this work, another microwave-assisted extraction method is proposed, also proposed by the UNE-EN-15549 standard “Standard method for measuring the concentration of benzo(a)pyrene in ambient air”, which is less tedious and decrease the use of solvents than ultrasonic assisted extraction. Thus, the objective of this work is to compare both extraction protocols for the PAHs, identified as priority pollutants by the EPA, in terms of extraction efficiencies and limits of detection (LOD) and quantification (LOQ). For the quantification of PAHs, HPLC chromatographic technique with fluorescence detection was used. The microwave-assisted extraction (MAE) protocol includes a volume reduction with the help of a rotary evaporator, until dry. Subsequently, the dry residue is reconstituted with hexane and passed through a fractionation column to eliminate the aliphatic compounds present in the sample. Finally, it is returned to dryness and reconstituted with acetonitrile. The results of microwave-assisted extractions showed acceptable extraction yields (between 50 and 101%). Furthermore, it is a less tedious methodology than the ultrasound extraction method, and presents lowest LODs and LOQs, for the most of PAHs. It can be concluded that MAE is more convenient, with a shorter analysis time, lower detection limits, and reduces the amount of solvents, being more friendly to the environment

Paper-Based Analytical Device for One-Step Detection of Bisphenol-A Using Functionalized Chitosan

Bisphenol-A (BPA) is defined as one of the endocrine disrupting compounds. The accurate and inexpensive colorimetric paper-based analytical devices (PADs) are of crucial importance for BPA analysis. In this context, we developed for the first time a new PAD modified with chitosan and sulfamethoxazole (Chitosan-PAD) for the visual detection of BPA in water. The PAD was characterized by Fourier-transform infrared spectroscopy, which confirmed its modification by the functionalized chitosan. A yellow coloration was developed when a small volume of BPA was added to the Chitosan-PAD, allowing for visual and smartphone detection. This new strategy is based on a specific combination of BPA with chitosan and sulfamethoxazole that provides a hight selectivity to the Chitosan-PAD. The proposed PAD was successfully employed in combination with a pre-concentration step for the detection of 0.01 µg mL−1 of PBA with the naked eye using a 10-fold preconcentration factor. The PAD was effectively applied for BPA quantification in water samples with good recoveries. The developed PAD provides a green and cost-effective strategy for the on-site and one-step detection of BPA in water samples

Pneumopathies à l'Anadron (à propos d'une observation)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF