MoS2 quantum dots for on-line fluorescence determination of the food additive allura red

[EN] This work presents an on-line fluorescence method for the allura red (AR) determination. The method is based on the fluorescence quenching of dots of MoS2 because of their interaction with the non-fluorescence dye. MoS2-dots were synthetized and characterized by spectroscopic techniques and High Resolution Transmission Electronic Microscopy (HR-TEM). The simultaneous injection of the nanomaterial and the dye in a flow injection analysis system allows the determination of allura red at 1.7 x 10(-6) M concentration level with a very good accuracy and precision (Er minor than 10% and RSD lower than 8%) and a sampling frequency of 180 samples per hour. Moreover, the interaction fluomphore-quencher results a dynamic inhibition mechanism. The proposed methodology was applied to the AR analysis in soft beverages and powders for gelatine preparation. Colourant concentrations of 63 +/- 2 mg/L (n = 3) and 0.30 +/- 0.01 mg/g (n = 3) were found, respectively. These results were validated by high performance liquid chromatography technique.The authors acknowledge financial support from the Spanish MICINN (MAT2017-85089-C2-2-R), the Comunidad Autonoma de Madrid (P2018/NMT-4349, TRANSNANOAVANSENS-CM).Coloma, A.; Del Pozo, M.; Martínez-Moro, R.; Blanco, E.; Atienzar Corvillo, PE.; Sánchez, L.; Petit-Domínguez, MD.... (2021). MoS2 quantum dots for on-line fluorescence determination of the food additive allura red. Food Chemistry. 345:1-8. https://doi.org/10.1016/j.foodchem.2020.128628S1834

Unveiling the collaborative effect at the cucurbit[8]urilMoS2 hybrid interface for electrochemical melatonin determination

Host-guest interactions are of paramount importance in supramolecular chemistry and in a wide range of applications. Particularly well known is the ability of cucurbit[n]urils (CB[n]) to selectively host small molecules. We show that the charge transfer and complexation capabilities of CB[n] are retained on the surface of 2D transition metal dichalcogenides (TMDs), allowing the development of efficient electrochemical sensing platforms. We unveil the mechanisms of host-guest recognition between the MoS2- CB[8] hybrid interface and melatonin (MLT), an important molecular regulator of vital constants in vertebrates. We find that CB[8] on MoS2 organizes the receptor portals perpendicularly to the surface, facilitating MLT complexation. This advantageous adsorption geometry is specific to TMDs and favours MLT electro-oxidation, as opposed to other 2D platforms like graphene, where one receptor portal is closed. This study rationalises the cooperative interaction in 2D hybrid systems to improve the efficiency and selectivity of electrochemical sensing platform

Template assisted electrodeposition of intricate BiTe structures

Trabajo presentado en la 17th European Conference on Thermoelectrics (ECT2019), celebrada en Limassol (Chipre), del 23 al 25 de septiembre de 201

Spongy Bi2Te3

Trabajo presentado en el European Materials Research Society (EMRS), celebrado en Niza (Francia), del 27 al 31 de mayo de 201

BD funcional cardiacos

Base de datos del artículo de efectos funcionales en rehabilitación cardiac

Electrodeposited Bi2Te3inside inter-connected hollowed polymers

Trabajo presentado en el 2nd Iberian Thermoelectric Workshop (ITW2019), celebrado en Ciudad Real (España), del 5 al 6 de septiembre de 2019Among the different thermoelectric materials available nowadays, bismuth telluride stands out as one of the most used in room temperature applications. In the last years, there have been many efforts to nano-structure this material in order to enhance its thermoelectric properties, in the form of thin films [1], nanowires [2], 3D nano-structures [3], etc. In this work we present a novel route to obtain bismuth telluride via template assisted electrochemical deposition. The material so deposited will replicate the hollow structure of different polymers, giving rise to spongy-like interconnected morphologies fabricated in a low-cost, easily transferrable to industry and straightforward way. Then, the main properties of these nano-structured spongy bismuth telluride structures will be studied from the morphological, crystallographical and transport points of view

Improvement of Seebeck coefficient in as-grown Bi2Te3-ySey electrodeposited films by the addition of additives and bath optimization

Bi2.0Te2.7Se0.3 is the most widely used thermoelectric n-type leg for large-scale cooling applications. However, as-grown electrodeposited Bi2Te3-ySey films typically have a Seebeck coefficient around a third of the bulk value, which sometimes can be improved with thermal annealings. In this work, we report as-grown Bi2Te3-ySey films having a Seebeck coefficient of approximately half the value of bulk without additional thermal treatments. All samples reported were deposited in baths containing no additives, sodium lignosulfonate (SLS), or both SLS plus ethylenediaminetetraacetic acid (EDTA) with a concentration of 1 M HNO3 (pH of 0 ± 0.1) and 0.6 M HNO3 (pH of 0.3 ± 0.1). For each scenario, the deposition was carried out at two different temperatures (0 °C and 5 °C). Seebeck values of −120 μV K−1 have been measured for as-grown films with an optimum morphology and stoichiometry (Bi2Te2.7Se0.3), which is ∼50% of the value obtained for this composition in bulk and the highest among as-grown electrochemically deposited films reported to date. These results are an incentive to revisit and further explore the chemistry behind the electrodeposition of bismuth telluride selenide films to improve the performance of electrodeposited thermoelectric films.M.M-G. acknowledges NSF IRES 1028071 support. D.-A. B.-T. acknowledge Fulbright fellowship support. M.M.G acknowledges the INFANTE, MAT2017-86450-C4-3-R and the ERC Starting grant NANO-Tec projects. O.C.C. wants to thank the financial support of Ramon y Cajal grant of the Spanish Government. The authors acknowledge the service from the X-SEM Laboratory at IMN, and funding from MINECO under project CSIC13-4E-1794 with support from EU (FEDER, FSE).Peer reviewe

MoS2 quantum dots for on-line fluorescence determination of the food additive allura red

This work presents an on-line fluorescence method for the allura red (AR) determination. The method is based on the fluorescence quenching of dots of MoS because of their interaction with the non-fluorescence dye. MoS-dots were synthetized and characterized by spectroscopic techniques and High Resolution Transmission Electronic Microscopy (HR-TEM). The simultaneous injection of the nanomaterial and the dye in a flow injection analysis system allows the determination of allura red at 1.7 × 10 M concentration level with a very good accuracy and precision (Er minor than 10% and RSD lower than 8%) and a sampling frequency of 180 samples per hour. Moreover, the interaction fluorophore-quencher results a dynamic inhibition mechanism. The proposed methodology was applied to the AR analysis in soft beverages and powders for gelatine preparation. Colourant concentrations of 63 ± 2 mg/L (n = 3) and 0.30 ± 0.01 mg/g (n = 3) were found, respectively. These results were validated by high performance liquid chromatography technique.The authors acknowledge financial support from the Spanish MICINN (MAT2017-85089-C2-2-R), the Comunidad Autónoma de Madrid (P2018/NMT-4349, TRANSNANOAVANSENS-CM).Peer reviewe

Electrochemical sensor based on the synergy between Cucurbit[8] uril and 2D‑MoS2 for enhanced melatonin quantification

We present the development of an electrochemical sensor towards melatonin determination based on the synergistic effect between MoS2 nanosheets and cucurbit[8]uril. For the sensor construction cucurbit[8]uril suspensions were prepared in water, and MoS2 nanosheets were obtained by liquid exfoliation in ethanol:water. The sensing platform was topographically characterized by Atomic Force Microscopy. Electrochemical Impedance Spectroscopy experiments allowed us to study the charge transfer process during melatonin oxidation. Moreover, stoichiometry of the resulting complex has also been determined. After the optimization of the sensor construction and the experimental variables involved in the Differential Pulse Voltammetric response of melatonin, detection limit of 3.80 × 10−7 M, relative errors minor than 3.8% and relative standard deviation lower than 4.4% were obtained. The proposed sensor has been successfully applied to melatonin determination in pharmaceutical and biological samples as human urine and serum, with very good recoveries ranging from 90 to 102%The authors acknowledge financial support from projects PID2020-113142RB-C21 and PID2020-113142RB-C22 and TED2021-129416A-I00 funded by MCIN/AEI/https://doi.org/10.13039/501100011033 and P2018/NMT 4349 (TRANSNANOAVANSENS-CM) funded by the Comunidad Autónoma de Madri

Unveiling the Collaborative Effect at the Cucurbit [8] uril–MoS2 Hybrid Interface for Electrochemical Melatonin Determination

[EN] Host-guest interactions are of paramount importance in supramolecular chemistry and in a wide range of applications. Particularly well known is the ability of cucurbit[n]urils (CB[n]) to selectively host small molecules. We show that the charge transfer and complexation capabilities of CB[n] are retained on the surface of 2D transition metal dichalcogenides (TMDs), allowing the development of efficient electrochemical sensing platforms. We unveil the mechanisms of host-guest recognition between the MoS2- CB[8] hybrid interface and melatonin (MLT), an important molecular regulator of vital constants in vertebrates. We find that CB[8] on MoS2 organizes the receptor portals perpendicularly to the surface, facilitating MLT complexation. This advantageous adsorption geometry is specific to TMDs and favours MLT electro-oxidation, as opposed to other 2D platforms like graphene, where one receptor portal is closed. This study rationalises the cooperative interaction in 2D hybrid systems to improve the efficiency and selectivity of electrochemical sensing platforms.Financial support from the Spanish MINECO (PID2020-113142RB-C21, PID2020-113142RB-C22, PLEC2021-007906), the Comunidad de Madrid (P2018/NMT-4349, TRANSNANOAVANSENS-CM, S2018/NMT-4367 FOTOARTCM and Y2020/NMT-6469- FOTOSURF-CM) and EU GrapheneEU Graphene Flagship core-3 program (881603