The use of nanocomposites in the microextraction context

La etapa de tratamiento de muestra es el cuello de botella de la mayoría de procedimientos analíticos. Su evolución en los últimos años ha estado marcada por la automatización, la miniaturización y la simplificación. Además, es la etapa que más influye en la calidad de la información obtenida. En general, las técnicas de tratamiento de muestra juegan un papel importante en la mejora de la sensibilidad, a través de la preconcentración de los analitos, y de la selectividad, por su aislamiento de la matriz de la muestra. La investigación desarrollada en esta Tesis Doctoral ha estado centrada en el diseño y empleo de nuevos materiales sorbentes en microextracción en fase sólida. Todos los materiales sintetizados pueden considerarse materiales híbridos o composites, ya que se obtienen por combinación de dos o más tipos de componentes. Estos materiales poseen la ventaja de combinar diferentes propiedades en un mismo material o de potenciar una de ellas y son ampliamente usados en técnicas de tratamiento de muestra. En este sentido, el uso de polímeros presenta una gran ventaja, ya que pueden ser diseñados a medida para favorecer la interacción con un determinado tipo de analitos. Así, pueden introducirse en la red polimérica varios grupos funcionales con características químicas diferentes (desde grupos no polares hasta de intercambio iónico). Además, su estabilidad química, mecánica y térmica, permite su uso en diversas técnicas de extracción, como: extracción en fase sólida (SPE) o microextracción en película delgada. Teniendo en cuenta lo anteriormente expuesto, la Tesis Doctoral ha tenido como objetivo general el avance en el campo de las técnicas de microextracción, haciendo uso de nuevos materiales sorbentes. En concreto, se han llevado a cabo diferentes síntesis de composites que combinan polímeros con nanopartículas (NPs) de diferente naturaleza, las cuales dotan a los materiales de nuevas propiedades. Dichos materiales se han aplicado a la resolución de problemas analíticos de carácter medioambiental, agroalimentario y clínico

Intercambio de ligando en nanopartículas de Au protegidas por monocapas de mercaptopurina

III Encuentro sobre Nanociencia y Nanotecnología de Investigadores y Tecnólogos Andaluce

Inclusive-photon production and its dependence on photon isolation in pp collisions at s√ = 13 TeV using 139 fb−1 of ATLAS data

Measurements of differential cross sections are presented for inclusive isolated-photon production in pp collisions at a centre-of-mass energy of 13 TeV provided by the LHC and using 139 fb−1 of data recorded by the ATLAS experiment. The cross sections are measured as functions of the photon transverse energy in different regions of photon pseudorapidity. The photons are required to be isolated by means of a fixed-cone method with two different cone radii. The dependence of the inclusive-photon production on the photon isolation is investigated by measuring the fiducial cross sections as functions of the isolation-cone radius and the ratios of the differential cross sections with different radii in different regions of photon pseudorapidity. The results presented in this paper constitute an improvement with respect to those published by ATLAS earlier: the measurements are provided for different isolation radii and with a more granular segmentation in photon pseudorapidity that can be exploited in improving the determination of the proton parton distribution functions. These improvements provide a more in-depth test of the theoretical predictions. Next-to-leading-order QCD predictions from JETPHOX and SHERPA and next-to-next-to-leading-order QCD predictions from NNLOJET are compared to the measurements, using several parameterisations of the proton parton distribution functions. The measured cross sections are well described by the fixed-order QCD predictions within the experimental and theoretical uncertainties in most of the investigated phase-space region

Charged-hadron production in pp, p+Pb, Pb+Pb, and Xe+Xe collisions at sNN−−−√ = 5 TeV with the ATLAS detector at the LHC

This paper presents measurements of charged-hadron spectra obtained in pp, p+Pb, and Pb+Pb collisions at s√ or sNN−−−√ = 5.02 TeV, and in Xe+Xe collisions at sNN−−−√ = 5.44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb−1, 28 nb−1, 0.50 nb−1, and 3 μb−1, respectively. The nuclear modification factors RpPb and RAA are obtained by comparing the spectra in heavy-ion and pp collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor RpPb shows a moderate enhancement above unity with a maximum at pT ≈ 3 GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct pT-dependence with a local maximum at pT ≈ 2 GeV and a local minimum at pT ≈ 7 GeV. This dependence is more distinguishable in more central collisions. No significant |η|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe RAA better in central collisions and in the pT range from about 10 to 100 GeV

Measurements of Zγ+jets differential cross sections in pp collisions at s√ = 13 TeV with the ATLAS detector

Differential cross-section measurements of Zγ production in association with hadronic jets are presented, using the full 139 fb−1 dataset of s√ = 13 TeV proton–proton collisions collected by the ATLAS detector during Run 2 of the LHC. Distributions are measured using events in which the Z boson decays leptonically and the photon is usually radiated from an initial-state quark. Measurements are made in both one and two observables, including those sensitive to the hard scattering in the event and others which probe additional soft and collinear radiation. Different Standard Model predictions, from both parton-shower Monte Carlo simulation and fixed-order QCD calculations, are compared with the measurements. In general, good agreement is observed between data and predictions from MATRIX and MiNNLOPS, as well as next-to-leading-order predictions from MADGRAPH5_AMC@NLO and SHERPA