Search

Current sample preparation strategies for nanomaterials (NMs) analysis in soils by means single particle inductively coupled plasma mass spectrometry have significant constrains in terms of accuracy, sample throughput and applicability (i.e., type of NMs and soils). In this work, strengths and weakness of microwave assisted extraction (MAE) for NMs characterization in soils were systematically investigated. To this end, different extractants were tested (ultrapure water; NaOH, NH4OH, sodium citrate and tetrasodium pyrophosphate) and MAE operating conditions were optimized by means of design of experiments. Next, the developed method was applied to different type of metallic(oid) nanoparticles (Se-, Ag-, Pt- and AuNPs) and soils (alkaline, acid, sandy, clayey, SL36, loam ERMCC141; sludge amended ERM483). Results show that Pt- and AuNPs are preserved and quantitatively extracted from soils in 6 min (12 cycles of 30 s each) inside an 800 W oven by using 20 mL of 0.1 M NaOH solution. This methodology is applicable to soils showing a wide range of physicochemical properties except for clay rich samples. If clay soil fraction is significant (>15%), NMs are efficiently retained in the soil thus giving rise to poor recoveries (<10%). Labile NMs such as Se- and AgNPs could not be analyzed by means this approach since extraction conditions favors dissolution. Finally, when compared to current extraction methodologies (e.g., ultrasound, cloud point extraction, etc.), MAE affords better or equivalent accuracies and precision as well as higher sample throughput due to treatment speed and the possibility to work with several samples simultaneously.

Microwave induced plasma optical emission spectrometry (MIP-OES) has gained widespread attention in the last few years for trace elemental analysis. Among the new generation of MIPs it is worth to mention the microwave-sustained inductively coupled atmospheric-pressure plasma (MICAP) for which previous works have shown similar detection capabilities to those afforded by ICP-OES. Nevertheless, this instrument has not been applied yet to complex matrix sample analysis. Therefore, the goal of this work is to evaluate MICAP-OES performance (e.g., analytical figures of merit, matrix effects, etc.) for elemental analysis of samples of different nature (e.g., environmental, food and polymers). To this end, both spectral and non-spectral interferences were investigated for 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mg, Mn, Ni, Pb, Sr, Tl, Zn) in the presence of inorganic acid, organic and saline solutions and compared to a 5 % w w−1 HNO3 solution. Unlike previous MIPs, experimental data showed that the optimum nebulizer gas flow rate for a given emission wavelength was mostly independent of matrix characteristics. Regarding matrix effects, this device was highly robust operating both inorganic acid and organic matrices. Interestingly, when operating saline matrices, changes on emission signal by easily ionizable elements were less significant than those early reported by alternative MIP cavities. Moreover, due to MICAP spectrometer design employed allows real-time simultaneous analysis, Rh, Pd, Sc and Y were suitable internal standards to minimize non-spectral interferences. Finally, MICAP-OES can be successfully applied to the elemental analysis of different complex matrix samples (i.e., CRM-DW1 Drinking water; BCR-146 Sewage sludge industrial; BCR-185 Bovine liver; BCR-278R Mussel tissue; NIST-1549 Non-fat milk powder; ERM-EC681k Polyethylene (high level) and BCR-483 Sewage sludge amended soil).

Microwave-assisted extraction (MAE) treatments seem to be a promising sample preparation strategy to isolate nanomaterials (NMs) from environmental samples prior to single particle inductively coupled plasma mass (spICP-MS) determination. Nevertheless, because previous studies make use of domestic microwave ovens (DMOs), several shortcomings arise that compromise the analysis such as lack of control of experimental variables, limited operating conditions, and uncontrolled sample heating leading to irreproducibility issues. The goal of this work is to adapt previously developed MAE treatments for soil and air filters with the DMO apparatus to state-of-the-art scientific microwave ovens (SMOs) in order to standardize current analytical protocols for NM characterization. Results show that, by working with an SMO, non-labile metallic NMs (Pt-AuNPs) are quantitively extracted from soil and air filter samples unaltered in 10 min and 6 min, respectively, at 1200 W by using 10 mL of NaOH 0.1 M solution. The use of a SMO system allows improving accuracy (above 10% of the particle recovery), precision (above 5% of the RSD) and sample throughput (above 4-fold) when compared to the DMO ones. According to these findings, MAE seems to be a powerful strategy for routine analysis of non-labile NMs in environmental samples.

It has been reported that volcanoes release several tonnes of mercury per year among other heavy metals through eruptions, fumaroles, or diffuse soil degassing. Since a high percentage of the world's population lives in the vicinity of an active volcano, the aim of this study is to evaluate the accumulation of these metals in the central nervous system and the presence of cellular mechanisms of heavy metal detoxification such as metallothioneins. To carry out this study, wild mice (Mus musculus) chronically exposed to an active volcanic environment were captured in Furnas village (Azores, Portugal) and compared with those trapped in a reference area (Rabo de Peixe, Azores, Portugal). On the one hand, the heavy metal load has been evaluated by analyzing brain and cerebellum using ICP-MS and a mercury analyzer and on the other hand, the presence of metallothionein 2A has been studied by immunofluorescence assays. Our results show a higher load of metals such as mercury, cadmium and lead in the central nervous system of exposed mice compared to non-exposed individuals and, in addition, a higher immunoreactivity for metallothionein 2A in different areas of the cerebrum and cerebellum indicating a possible neuroprotection process.

Haloferax mediterranei has revealed a high bioremediation potential for several inorganic anions (e.g., nitrates and nitrites) and metals from hypersaline waters and brines. However, it is unclear, to date, whether this microorganism allows Cd (II) bioremediation. Consequently, the main objective of this work was to assess the Cd (II) bioremediation potential of Hfx. mediterranei R4. To this end, Hfx. mediterranei cell growth rate and metal bioaccumulation were investigated using different culture media (complex, CM, and defined medium, DM) containing Cd (II) up to 1 mM. In addition, the elemental profile of the biomass (i.e., Al, Ba, Ca, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Sr and Zn) has also been monitored to gain insight into the metabolic processes that may be taking place at the intracellular level for Cd (II) removal. Because of the formation of CdS precipitate, CM is not a suitable culture media for evaluating Cd bioremediation since metal concentration could not be appropriately controlled. When operating in DM, it was observed that the cell doubling time increases three times in the presence of Cd (II). Hfx. mediterranei can bioaccumulate Cd, showing the highest significant accumulation at concentrations of 0.4 mM (108 ± 12 mg Cd/g dry tissue). Finally, the presence of Cd (II) affects the content of K, Mg, Mn and Zn in the biomass, by increasing K levels up to 27 ± 18% and Mn up to 310 ± 140% and reducing Mg levels up to 55 ± 36% and Zn up to 30 ± 4%. These results suggest that different mechanisms are involved in Cd (II) tolerance by Hfx. mediterranei, resulting in increasing the cell concentration of stress-tolerant elements in the biomass (K and Mn), while lowering the concentration of elements which Cd (II) competes with (Mg and Zn), and that all affects the physiological response of the organism by decreasing its growth rate.

The Tsuji–Trost reaction of allylic acetates with nucleophiles is optimized using a task-specific ionic liquid (TSIL)-palladium complex in a very efficient manner. Several nucleophiles and allylic systems are studied obtaining very high yields of the corresponding products with total n-selectivity. The reaction is surveyed employing inexpensive allylic alcohols and 3-acyloxindole derivatives affording the expected allylated molecules after a deacylative process. The robustness of the catalytic system is assessed. The recovery and recycling of the whole catalytic system with the ionic liquid is also analyzed and the results are compared with previously reported articles in the literature.

Whey protein (WP) as a dietary supplement for athletes and gym-users is characterized by a content of high-quality amino acids. The benefits of their consumption are well-known and mainly related to the improvements of strength and body composition. Nevertheless, there is a scarce information about the risk associated to their elemental composition. The aim was to evaluate the total content and bioavailability of twenty-five elements in twenty whey protein powder samples, using Inductively Coupled Plasma Mass Spectrometry, and to evaluate the possible risk associated to the excessive daily intake of such products. Results showed that Na, K, Ca and Mg were the most predominant elements. After Hierarchical Cluster Analysis three different groups of whey protein supplements were observed. ANOVA analysis indicates that the concentration of the Na, K and Mg above mentioned elements is the key for the observed classification. The average elemental bioavailable fraction in the stomach is 45 % whereas in the intestine is 64 %. Most of the elements tested (nineteen) show gastric bioavailability higher than 60 %, being Al the lowest (37 %) and Co the highest one (76 %). According to our results, previously published data and recommendations of producers, WP samples can be considered save from the elemental composition point of view.

The number of works devoted to nanomaterials characterization in organic matrices by means spICP-MS grows every year, but limited information is available about the non-spectral interferences generated by this type of matrices. A better understanding of this interference is a prerequisite for developing more robust methodologies and improving spICP-MS metrology. The goal of this work is to investigate non-spectral interferences due to organics on nanoparticles (NPs) characterization (i.e., number concentration and size distribution) by means spICP-MS. To this end, the influence of NPs composition and size (i.e., Au-, Pt- and SeNPs), carbon source (i.e., 6% w w-1 glycerol and 10% w w-1 ethanol), ICP-MS operating conditions (i.e., sampling depth and nebulizer gas flow) and instrument design on matrix effects have been evaluated. It was observed that 10% w w-1 ethanol give rise to positive matrix effects on the number concentration due to changes on aerosol generation and transport with regard water standards. Irrespective of the organic source employed, either positive or negative bias on the size distributions can be obtained and these effects depend on plasma operating conditions, instrument characteristics and NPs composition. In addition to changes on transport efficiency, matrix effects on size distribution also depend on plasma characteristics and carbon-based charge transfer reactions (Au and Se). Organic non-spectral interferences can be mitigated by means internal standardization. When operating with 10% w w-1 ethanol, two internal standards (ionic solution plus a NPs suspension of known concentration) are simultaneously required for correcting changes on analyte ionization and transport. For 6% w w-1 glycerol, however, just a single internal standard (ionic solution) is necessary since this matrix does not affect aerosol generation and analyte transport. A novel measurement procedure is proposed for measuring the internal standards and the NPs of interest wi

Single particle inductively coupled plasma mass spectrometry (spICP-MS) has been explored for the determination of metallic nanoparticles (NPs) in air. Different extraction strategies (i.e., direct immersion, hard cap espresso, ultrasound-assisted and microwave-assisted extraction) and extracting solvents (i.e., citric acid, trisodium citrate, potassium nitrate, sodium nitrate, thiourea, disodium pyrophosphate and ammonium hydroxide) were investigated for platinum and gold NPs recovery from glass and microquartz fiber filters with a nominal size cut-off of 300 nm. Results show that metallic NPs are preserved and quantitatively extracted from the filter in 4 min inside an 800 W microwave oven by using 40 mL of a 2.0% w w−1 NH4OH solution. For the remaining extraction procedures, either incomplete recoveries or NPs degradation occur. As regards the influence of filter material, microquartz fiber affords better NPs capturing performance than glass fiber ones, enabling the quantification of NPs with diameters above 28 nm. This methodology has been successfully applied to determine PtNPs in filters from environmental monitoring stations and to gain insight into NPs transport through ICP-MS sample introduction system. Care should be taken during spICP-MS calibration since biased results might be obtained due to differences on NPs transport efficiency between standards and samples.

Se propone incentivar el interés de los más jóvenes por la ciencia y promover actitudes críticas a través de dos experimentos de laboratorio: ¿Quién anda ahí? y Fuego de colores: el secreto de los fuegos artificiales.

Los indicadores académicos de la signatura Química de las Disoluciones del Grado en Ciencias del Mar de la Universidad de Alicante son significativamente inferiores al promedio de la titulación. Este trabajo continúa con el estudio comenzado en la red del año pasado, implementando las nuevas estrategias docentes y analizando la satisfacción del alumnado con las mismas. Con este fin, se ha distribuido una encuesta al alumnado del curso académico 2020-2021 de Química de las Disoluciones del Grado en Ciencias del Mar de la Universidad de Alicante. A través de las encuestas se pretende conocer la opinión de los alumnos y alumnas de las nuevas metodologías docentes implantadas durante este curso. Además, estas nuevas estrategias se adaptan a la nueva situación generada por la pandemia asociada a la COVID-19, ya que se fomenta el trabajo no presencial tanto en las clases de teoría como en las de prácticas. La información obtenida del alumnado junto con las reflexiones sobre la misma del profesorado que constituye esta red puede ser de gran utilidad para mejorar los indicadores académicos y el proceso de enseñanza-aprendizaje en la asignatura de Química de las Disoluciones del Grado en Ciencias del Mar de la Universidad de Alicante.

In the past few years, microwave induced plasma optical emission spectrometry (MIP-OES) has generated great interest as an alternative technique to inductively coupled plasma-based techniques due to its lower operational cost. Since MIP-OES suffers from severe matrix effects due to easily ionizable elements (EIEs) (Na, Ca, etc.), it is unclear whether this technique could be employed for elemental bioavailability studies in soils and sediments since the main extractant solutions employed in such works may contain high levels of these elements. Thus, the aim of this work was to evaluate the feasibility of MIP-OES as a detector for such applications. To this end, the influence of different extractant solutions (0.25 mol L−1 MgCl2, 0.25 mol L−1 CaCl2, 0.10 mol L−1 acetic acid, 0.05 mol L−1 Na2EDTA, 0.25 mol L−1 NaNO3, 0.25 mol L−1 NaOAc/HOAc and 0.10 mol L−1 NH2OH·HCl) on the analyte emission of several elements (As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Rh, Se, Sr and Zn) was investigated. Results were compared to those obtained using a reference solution made of 5% w w−1 HNO3 solution. For saline extractant solutions, both the optimum nebulizer gas flow rate (Qg) and analyte emission were modified with regard to the reference solution. In general, the optimum Qg was reduced by between 0.1 and 0.2 L min−1 for both ionic and atomic lines. Under optimum Qg conditions, analyte emission was supressed by saline solutions except for atomic lines with an upper electronic state below 4 eV, which were enhanced. The magnitude of matrix effects was strongly dependent on EIE ionization energy. The lower the ionization energy, the greater the matrix effects were registered. No measurable matrix effects were registered on both Qg and analyte emission within experimental uncertainties for NH2OH·HCl and acetic acid extractant solutions. Experimental data suggest that matrix effects were related to changes in plasma characteristics and the analyte excitation/ionization mechanism. To

Inductively coupled plasma mass spectrometry (ICP-MS) has been traditionally employed in life sciences for total element content and speciation studies. Nonetheless, using element-tagged antibodies, ICP-MS also serves as a detector for immunoassays thus allowing the determination of organic molecules (i.e. proteins, biomarkers, toxins, etc.) and cells. When compared to conventional immunoassay detection approaches (e.g. fluorescence, UV/VIS absorbance, etc.), ICP-MS offers several unique and attractive features such as: (i) high sensitivity and selectivity; (ii) multiplexed capabilities; (iii) large dynamic range; and (iv) robustness for the analysis of both liquid and solid samples. However, despite the above-mentioned features, immunoassays based on ICP-MS detection are mostly unknown among scientists in life sciences and not real breakthrough has yet produced for routine clinical applications. This work reviews the most recent developments and applications of immunoassays based on ICP-MS detection over the last years, emphasising current challenges and future trends of this promising analytical tool.

In inductively coupled plasma optical emission spectrometry (ICP-OES), the presence of carbon in the matrix strongly affects (positively and negatively) the emission signal of atomic lines. However, the emission signal of ionic lines is mostly unaffected by this concomitant. The goal of this work is to gain insight into the origin of carbon matrix effects on the signal of atomic lines in ICP-OES. To this end, the emission signal of a total of 3608 lines (i.e., 1755 atomic and 1853 ionic lines) of 62 elements (Ag, Al, As, Au, B, Ba, Be, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hg, Ho, I, In, Ir, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Re, Rh, S, Sb, Sc, Se, Sm, Sn, Sr, Tb, Te, Th, Ti, Tm, U, V, Y, Yb, Zn and Zr) were registered for carbon containing solutions (20 g L−1) prepared from glycerol. Results were compared to those obtained operating a 1% w w−1 HNO3 solution. Compared to the HNO3 reference solution, emission signals for As, B, Hg, I, P, Se and Te atomic lines were increased for the carbon containing solution. However, signal suppression was noticed for the signal emission of Ag, Al, Ba, Be, Ca, Cd, Co, Cr, Cs, Eu, Fe, Ga, Ge, K, Ho, In, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Ni, Pb, Pd, Pr, Pt, Re, Rh, S, Sb, Sc, Sn, Sr, Ti, Tm, V, Y and Zr atomic lines. No measurable matrix effects within experimental uncertainties were registered for Au, Cu, Ir, Gd and Zn atomic lines. As regards Ce, Dy, Er, Nd, Sm, Tb, Th, U and Yb no clear conclusion about matrix effects was feasible due to the limited atomic emission wavelengths monitored. Experimental results showed that the intensity of matrix effects depends on both analyte ionization energy and the energy of the electronic upper level involved in the electronic transition. Matrix effects on atomic emission lines can be explained by the simultaneous occurrence of different mechanisms: (i) charge transfer reactions; (ii) collisional ionization; and (iii) collisional excitation with carbon

Los líquidos iónicos (IL) son unos disolventes constituidos principalmente por pares iónicos y cuyo punto de fusión se encuentra por debajo de los 100 ºC. Desde su descubrimiento a principios del siglo XX hasta la actualidad, el uso de los ILs en todos los campos de la Química ha experimentado un crecimiento exponencial debido a sus propiedades físicoquímicas únicas (e.g. estabilidad química, conductividad, presión de vapor, etc.). En este sentido, los ILs pueden funcionalizarse con diferentes grupos funcionales de tal forma que presenten propiedades adicionales (task-specific ionic liquids, TSILs). Así, por ejemplo, los TSILs se han utilizado en catálisis en combinación con diversos metales o como agente quelantes para la recuperación de metales. A pesar de los númerosos estudios realizados hasta la fecha, sigue habiendo un gran desconocimiento a cerca del potencial de los TSIL en catálisis y extracción-preconcentración de metales. En la presente Tesis Doctoral se ha sintetizado el TSIL hexafluorofosfato de 1-butil-2-(difenilfosfino)-3-metilimidazolio y, gracias a su capacidad coordinante por el grupo fosfano, se ha empleado en combinación con diversos metales como catalizador de: (i) cicloadiciones 1,3-dipolares de iluros de azometino y alquenos electrofílicos (metal: Ag); (ii) acoplamientos Suzuki-Miyaura (metal: Pd); y (iii) alilaciones Tsuji-Trost (metal: Pd). En todos los casos, los complejos catalíticos formados muestran una gran eficiencia catalítica y reciclabilidad (>8 ciclos catalíticos). Por otro lado, debido a la estabilidad de los complejos formados entre este TSILy Pd, se ha desarrollado un método de análisis para determinar Pd en productos farmacéuticos. Para ello, se utilizó una metodología basada en la microextracción líquido-líquido y la determinación de Pd se realizó mediante espectroscopía de emisión óptica con plasma acoplado inductivamente. Los resultados obtenidos muestran que esta nueva metodología analítica presenta numerosas ventajas (i.e.

Los indicadores académicos de la signatura Química de las Disoluciones (QD) del Grado en Ciencias del Mar de la Universidad de Alicante son significativamente inferiores al promedio de la titulación. El objetivo de esta Red Docente es identificar qué aspectos y contenidos de QD presentan una mayor dificultad con objeto de seleccionar e implementar las metodologías docentes más adecuadas para motivar a los estudiantes y garantizar que se alcanzan los resultados de aprendizaje previstos en la Guía Docente de la asignatura. Con este fin, se ha distribuido una encuesta a los estudiantes que están cursando la asignatura este año, así como los que ya la han superado, para identificar sus dificultades. Según la información obtenida, las dificultades están relacionadas con una formación deficiente en Matemáticas y Química que les dificultad enormemente el aprendizaje y el trabajo no presencial y, como resultado, se produce una gran desmotivación. Para revertir esta situación, se propone modificar la metodología de trabajo (i.e. seminarios, tutorías y prácticas de laboratorio) y evaluación y la elaboración de material docente específico para las actividades no presenciales.

This work explores, for the first time, the strengths and weaknesses of the Conical torch in ICP-OES operating methanol and 1-propanol solutions ranging from 30% to 100% w w−1. To this end, Conical torch performance has been evaluated considering: (i) plasma fundamental properties; (ii) plasma robustness; (iii) carbon-based background emission; and (iv) analytical figures of merit. For the sake of comparison, a Fassel torch has been employed as a reference. Results show that the discharge for the Conical torch is highly robust and plasma characteristics (i.e., excitation temperature and electron number density) are mostly unaffected by the introduction of pure and hydroalcoholic solutions of methanol and 1-propanol. In contrast, the discharge for the Fassel torch is severely affected by organics introduction and it is not feasible to operate methanol solutions above 30% w w−1. Because torch geometry and improved gas flow patterns, the Conical torch affords higher emission signal (2-fold) than the Fassel torch. Nevertheless, the detection limits for both torches are comparable, which is due to the increase in both (carbon-based) background emission and signal noise for the Conical torch. From these results and considering that the Conical torch requires less r.f. power (35%) and argon consumption (55%) than the Fassel one, it is beyond doubt that the former torch is more advantageous for those applications requiring the analysis of alcohol solutions (i.e. extraction procedures and chromatographic separations).

Determination of As, Cd and Pb in food samples by means of inductively coupled plasma optical emission spectrometry (ICP-OES) is challenging due to detection limits being close to the maximum levels established by current international food security policies. This work evaluates the benefits and drawbacks of knotted reactor extraction (KR) and dispersive liquid–liquid microextraction (DLLME) for the simultaneous ultratrace determination of the above-mentioned elements by ICP-OES. To this end, ICP-OES experimental conditions were optimized to minimize the negative effects of organics on plasma characteristics. Next, both KR and DLLME were optimized using the experimental design for the simultaneous As, Cd and Pb preconcentration. KR- and DLLME-ICP-OES methods were compared and applied to the analysis of different food samples, representative of the commodities regulated by the EU policy. Results in this work show that both KR and DLLME allow successful toxic element analysis in foods according to current EU policies. Nevertheless, DLLME is a more attractive approach than KR. First, DLLME allows the simultaneous determination of As, Cd and Pb, while KR is just limited to the last two elements, since As-complexes are not efficiently retained within the system. When compared to conventional ICP-OES analysis (i.e., no preconcentration), DLLME improves limits of detection (LOD) on average by 40-fold for As, Cd and Pb, whereas KR improves it by just 10-fold. For both methodologies, LOD improvement is derived from the preconcentration procedure as well as the beneficial effect of organics on aerosol generation and transport to the plasma compared to aqueous samples. Finally, DLLME affords higher sample throughput and consumption index than KR.

La determinación de metales y metaloides en muestras medioambientales se suele realizar mediante técnicas de Espectrometría Atómica debido a su: (i) exactitud y precisión; (ii) sensibilidad; (iii) límites de detección del orden de los µg kg-1 - ng kg-1; (iv) velocidad de análisis; y (iv) capacidad multielemental para determinar varios analitos de forma simultánea. No obstante, el análisis de muestras medioambientales mediante estas técnicas no está exento de dificultades ya que la matriz de este tipo de muestras (p. ej. sales, materia orgánica, etc.), así como los reactivos empleados durante el pretratamiento de muestra (p. ej. ácidos, disolventes orgánicos, etc.), pueden dar lugar a interferencias (espectrales y no espectrales) que afecten negativamente a la exactitud y precisión de los análisis. A pesar de los numerosos estudios realizados hasta la fecha, existe todavía un gran desconocimiento sobre el origen de los efectos de matriz en las técnicas de Espectrometría Atómica y, en particular, para la Espectrometría de Emisión Atómica de Plasma Acoplado Inductivamente (ICP-AES) y la Espectrometría de Emisión Atómica de Plasma Inducido por Microondas (MIP-AES). En la presente Tesis Doctoral se han estudiado los efectos de matriz derivados de los concomitantes más habituales en el análisis de muestras medioambientales (sales, ácidos y carbono) sobre la señal de emisión en ICP-AES y MIP-AES y, a partir de la información obtenida, se han desarrollado diferentes métodos analíticos para la determinación de metales y metaloides en muestras medioambientales libres de interferencias. En primer lugar, se ha investigado la influencia del C sobre la señal de emisión (atómica e iónica) en ICP-AES para 62 elementos y sus posibles implicaciones prácticas al analizar muestras medioambientales. A partir de los conocimientos obtenidos, se ha desarrollado un método analítico para evaluar el papel de la Cymodocea nodosa en la movilización de elementos traza en el ecosistema marino de

Con objeto de garantizar la calidad de los alimentos tanto desde el punto de vista nutricional como toxicológico, existen diferentes normativas a nivel internacional para el control del contenido de metales y metaloides en alimentos. Este tipo de determinaciones se suele llevar a cabo mediante técnicas de Espectrometría Atómica por su sencillez y parámetros analíticos (p.ej. límite de detección, precisión, velocidad, etc.). No obstante, debido a la complejidad que presentan las matrices de los alimentos (i.e. grasas, proteínas, etc.) y a los bajos niveles de concentración de algunos elementos, se requiere de un tratamiento de extracción-preconcentración previo. Con este fin, se ha utilizado en la bibliografía la Microextracción Dispersiva Líquido-Líquido (DLLME). Sin embargo, el uso combinado de DLLME y técnicas de Espectrometría Atómica para la determinación de metales en alimentos sigue presentado limitaciones, como: (i) empleo de disolventes extractantes no adecuados según los principios de la Química Verde; (ii) escaso aprovechamiento del acoplamiento de DLLME y la Espectrometría de Emisión mediante Plasma de Acoplamiento Inductivo (ICP-AES) por los efectos de matriz que producen los extractantes orgánicos en el plasma; (iii) falta de criterio para seleccionar las condiciones de trabajo óptimas en ICP-AES para trabajar con extractos de DLLME; y (iv) escasa aplicación de DLLME a muestras de alimentos complejas (p.ej. vino, chocolate, etc.). En la presente Tesis Doctoral se han desarrollado nuevos métodos de análisis elemental en alimentos mediante el uso combinado de la Microextracción Dispersiva Líquido-líquido (DLLME) y técnicas Espectroscópicas Atómicas. En primer lugar, se ha investigado la posibilidad de utilizar el líquido iónico hexafluorofosfato de 1-butil-3-metilimidazolio como medio de extracción en DLLME para la determinación de Cd y Pb en muestras de vino mediante Espectrometría de Absorción Atómica con Horno de Grafito. Los resultados demuestran que

The 1-butyl-3-methyl-2-(diphenylphosphino)imidazalolium hexafluorophosphate is prepared and used as a water-soluble ligand in the Suzuki-Miyaura reaction. This ligand and palladium chloride generates a new active catalyst for the Suzuki coupling reaction between aryl iodides or bromides with arylboronic acids in neat water. This catalyst can be recycled and reused for the coupling reaction of 4-bromobenzonitrile with phenylboronic acid for at least six runs with low decreasing in catalytic activity.

Fundamental studies about non-spectral interferences in high-power microwave induced plasma optical emission spectrometry (MIP-OES) are very limited so far. The goal of this work is to investigate non-spectral interferences originating from calcium (0.5% w w−1 calcium nitrate), carbon (5.0% w w−1 glycerol) and sulfur (5.0% w w−1 sulfuric acid) matrices in commercial high-power MIP-OES based on a Hammer cavity. To this end, the influence of the nebulizer gas flow rate on the signal of several atomic and ionic lines of a total of 10 elements (As, Co, Cu, Mg, Mn, Mo, Sc, Se, Sr and Zn) has been studied for each matrix. Compared to the 1.0% w w−1 nitric acid reference solution, the emission signal for atomic lines with Esum values lower than 3.26 eV was enhanced in the presence of calcium but it was suppressed for the remaining atomic and ionic lines tested. Calcium matrix effects originate from changes in both plasma excitation conditions and ion–atom equilibrium. With regard to the 5.0% w w−1 glycerol and 5.0% w w−1 sulfuric acid solutions, no signal changes were noticed for the 1.0% w w−1 nitric acid solution since no significant differences were observed either in the aerosol size and transport or in the plasma excitation conditions. A comparison of matrix effects in MIP-OES with those obtained in inductively coupled plasma optical emission spectrometry (ICP-OES) under similar experimental conditions reveals that the former source is more sensitive to the presence of the calcium matrix. In contrast, MIP-OES is a more robust technique for elemental analysis when operating with 5.0% w w−1 glycerol and 5.0% w w−1 sulfuric acid solutions. In fact, matrix-based signal enhancements observed in ICP-OES for As and Se are eliminated when operating in MIP-OES.

The synthesis of a task‐specific ionic liquid (TSIL) based on a BMIM ionic liquid phosphane is achieved by modification of the original procedure. It is used as a ligand with AgOAc, and the resulting complex is fully characterized. This catalytic system promotes the 1,3‐dipolar cycloaddition of stabilized azomethine ylides and electrophilic alkenes using a green methodology. The green character was analyzed using an overall set of parameters finding the optimal conditions and individualized separation/purification methods for each cycloadduct. The determination of the most important green metrics is reported in this survey, demonstrating the value of this methodology on a laboratory scale or even at an industrial level.

During mining activities historically developed at Sierra Minera (Cartagena-La Unión, Spain), high amounts of trace elements were discharged to the Mar Menor coastal lagoon mainly through El Beal Wadi. The objective of this study is to establish the role played by the Cymodocea nodosa in the coastal marine dynamics of trace elements at the mouth of the wadi. To this end, the content of nine trace elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in different marine environmental compartments (i.e. marine and coastal sediments, C. nodosa tissues collected from live seagrass and C. nodosa beach cast litter) at two different locations were determined by inductively coupled plasma atomic emission spectrometry. The results showed that the seagrass C. nodosa could mobilise part of the elements present in marine sediments and water, thereby causing their re-accumulation in the coastal sediments through the C. nodosa beach cast litter.

El creciente número de estudiantes con necesidades especiales en las universidades españolas ha dispuesto que se empiecen a tomar medidas para regular la docencia de este tipo de estudiantes. En base a esto, la Universidad de Alicante creó en el año 2015 un documento que regulaba los derechos de estos estudiantes en función de la necesidad que tuvieran, concediéndoles lo que se denomina adaptaciones curriculares. Sin embargo, la implantación de estas adaptaciones no ha sido tarea fácil. La incorporación de una plataforma para gestionarlas ha deshumanizado el proceso. Los estudiantes no se ponen en contacto con los docentes porque piensan que al estar la aplicación no es necesario y, como consecuencia, muchos docentes desconocen quienes son los estudiantes a los que tienen que aplicar la adaptación curricular. Y entre docentes y estudiantes se encuentra el Programa de Acción Tutorial (PAT), que se encarga de hacer de intermediario para controlar que el proceso de adaptación curricular se realice con normalidad. Por este motivo, este curso 2017-2018 el PAT de la Facultad de Ciencias ha querido hacer un estudio del funcionamiento de las adaptaciones curriculares para detectar las posibles deficiencias en el proceso y mejorarlas en cursos posteriores.

Haptens (i.e. biomolecules which molecular weight is lower than 10 kDa) determination by inductively coupled plasma mass spectrometry (ICP-MS) is usually performed by means of competitive immunoassays. In these immunoassays, analyte quantification is indirectly carried out using two different tracer species (i.e. antibodies or antigen-protein conjugates). However, the benefits (and drawbacks) derived from using a given tracer species have not been systematically investigated so far. The goal of this work is to evaluate the influence of the tracer species employed in competitive immunoassays on the analytical figures of merit for aflatoxin M1 (AFM1) determination in milk samples. To this end, three different strategies have been developed and evaluated, namely: (i) antibody binding inhibition assay (ABIA); (ii) capture inhibition assay (CIA); and (iii) capture bridge inhibition assay (CBIA). Experimental results show that the use of the antibody as tracer species (as in the ABIA approach) affords better analytical figures of merit for AFM1 determination than using the antigen-protein conjugate as the tracer one (as in the CIA and CBIA strategies). The limit of detection afforded by ABIA strategy (i.e. 0.1 ng kg-1) for AFM1 determination was 1000-fold and 50-fold lower regarding the CIA and CBIA strategies, respectively. In the case of the ABIA approach, the characteristics of the metal nanoparticle label employed to detect the tracer species is critical on the analytical figures of merit. However, when the hapten-protein conjugates are used as tracer species, immunocomplex formation is severely hampered by steric effects caused by the protein moiety and, consequently, the characteristics of the metal nanoparticle label is not critical in the immunoassay performance. The different immunoassay strategies were successfully validated for AFM1 determination in milk samples using a certified reference material of whole milk powder (ERM-BD283) according to European Conformi

Este trabajo analiza y revisa la metodología usada para el asesoramiento y supervisión de alumnado propio y acogido en programas de movilidad nacionales e internacionales en la Facultad de Ciencias de la Universidad de Alicante (UA). Con la investigación realizada en el marco de este proyecto se han identificado las debilidades y fortalezas de los métodos de asesoramiento y supervisión académica tanto de alumnado propio de la Facultad que cursa estudios en otras universidades españolas o extranjeras, así como de alumnado nacional e internacional acogida en nuestra Facultad. Con los resultados de dicho análisis, se realiza una propuesta de acciones de mejora para el proceso de asesoramiento y supervisión (antes, durante y al finalizar la movilidad). Las asignaturas donde se implantarán en el curso 18-19 los resultados de esta investigación docente son todas las que constituyen los títulos de Grado de la Facultad de Ciencias de la Universidad de Alicante.

La Espectrometría de Masas mediante ionización en Plasma Acoplado Inductivamente (ICP-MS) es una técnica de análisis elemental que permite cuantificar la mayor parte de los elementos de la tabla periódica de forma rápida y a niveles de ultratraza. A lo largo de la última década, y debido a sus características analíticas, el ICP-MS se ha utilizado como sistema de detección en inmunoensayos para la determinación de bioméculas. A pesar de los avances que se han producido, este tipo de estrategias todavía no están exentas de inconvenientes. Entre los retos que aún están por resolver, se encuentran: (i) desarrollo de metodologías para la determinación de haptenos (biomoléculas de bajo peso molecular < 10 kDa), (ii) falta de criterio para seleccionar el tipo de inmunoensayo más adecuado para una aplicación bioanalítica dada, sobre todo cuando se trabaja con haptenos; y (iii) escaso aprovechamiento del potencial del ICP-MS (sensibilidad, límites de detección, capacidad de análisis multielemental, etc.). En la presente Tesis Doctoral se han desarrollado nuevos métodos de análisis de biomoléculas con detección mediante ICP-MS tratando de solucionar los inconvenientes citados con anterioridad. Los métodos se han aplicado al análisis de tóxinas en alimentos y de biomarcadores oncológicos en fluidos biológicos (suero). En primer lugar, debido a la gran preocupación existente por la seguridad alimentaria y el efecto de la alimentación sobre la salud humana, se ha desarrollado una nueva metodología para la cuantificación de la aflatoxina M1 (hapteno) en muestras de leche que cumpliera con los niveles de seguridad requeridos por las actuales políticas internacionales. Por otro lado, se han comparado diferentes formatos de inmunoensayos competitivos para la determinación de esta misma aflatoxina en leche. Además se ha estudiado el efecto de la naturaleza química y del tamaño de las nanopartículas (es decir, Ag / Au, 80 nm / 40 nm) empleadas en los inmunoensayos sobre los parámetros

Lanthanide polymer-labelled antibodies were investigated to improve the analytical figures of merit of homogeneous immunoassays with inductively coupled plasma mass spectrometry (ICP-MS) detection for multiplexed biomarker analysis in human serum samples. Specific monoclonal antibodies against four cancer biomarkers (CEA, sErbB2, CA 15.3 and CA 125) were labelled with different polymer-based lanthanide group to increase the number of metal labels per binding site. After the immunoreaction of the biomarkers with the specific antibodies, antigen-antibody complexes were separated by size-exclusion chromatography followed by ICP-MS detection. The polymer label could be loaded with 30-times more atoms of the lanthanide that the lanthanide-DOTA complex traditionally used for this purpose elsewhere [1] which resulted in a 10-fold improvement in both sensitivity and detection limits. Analytical figures of merit obtained with the lanthanide polymer labelling strategy make the detection of the biomarkers feasible below the threshold reference values used in clinical analysis. This labelling method was successfully validated by analyzing a control human serum spiked with the four biomarkers at three different concentration levels. For all the biomarkers studied, the recovery values ranged from 95% to 110% whereas inter-assay and intra-assay precision were lower than 8%. Results obtained with this approach were equivalent to those obtained by heterogenous-based immunoassays based on the detection by electro-chemiluminescence or ELISA. However, the method developed offers better analytical figures of merit using a smaller amount of sample.

Coupling dispersive liquid-liquid micro-extraction (DLLME) to inductively coupled plasma atomic emission spectrometry (ICP-AES) is usually troublesome due to the limited plasma tolerance to the organic solvents usually employed for metal extraction. This work explores different coupling strategies allowing the multi-element determination by ICP-AES of the solutions obtained after DLLME procedures. To this end, three of the most common extractant solvents in DLLME procedures (1-undecanol, 1-butyl-3-methyl-imidazolium hexafluorophosphate and chloroform) have been selected to face most of the main problems reported in DLLME-ICP-AES coupling (i.e., those arising from the high solvent viscosity and volatility). Results demonstrate that DLLME can be successfully coupled to ICP-AES after a careful optimization of the experimental conditions. Thus, elemental analysis in 1-undecanol and 1-butyl-3-methyl-imidazolium hexafluorophosphate extracts can be achieved by ICP-AES after a simple dilution step with methanol (1:0.5). Chloroform can be directly introduced into the plasma with minimum changes in the ICP-AES configuration usually employed when operating with aqueous solutions. Diluted inorganic acid solutions (1% w w−1 either nitric or hydrochloric acids) have been successfully tested for the first time as a carrier for the introduction of organic extractants in ICP-AES. The coupling strategies proposed have been successfully applied to the multi-element analysis (Al, Cu, Fe, Mn, Ni and Zn) of different water samples (i.e. marine, tap and river) by DLLME-ICP-AES.

En los últimos cursos, el Programa de Acción Tutorial (PAT) de la Facultad de Ciencias de la Universidad de Alicante se ha centrado en organizar cursos y seminarios que pudieran ser aprovechados por todos sus estudiantes. Cursos sobre técnicas de estudio y organización, planificación de cara a los exámenes, o seminarios sobre movilidad europea y no europea son algunas de las actividades que se realizaron en cursos anteriores. En el presente curso 2016/2017, el curso que se decidió organizar para nuestros estudiantes se tituló “Prepara tu futuro laboral: emprendimiento y búsqueda de empleo,” cuyos objetivos principales fueron presentarles herramientas para la búsqueda de empleo, enseñarles las herramientas sobre emprendimiento y los servicios disponibles que tiene la universidad en el caso que quieran montar una empresa, y las salidas profesionales que tienen las titulaciones de Ciencias. Una vez finalizado el curso, se les pasó a todos los estudiantes asistentes una encuesta de opinión, donde indicaron principalmente cuáles fueron las charlas que les parecieron más interesantes. Las charlas sobre herramientas para la búsqueda de empleo fueron las más valoradas, seguidas de las charlas sobre la investigación cómo salida laboral y la preparación de las oposiciones de secundaria.

Desde el PAT de la Facultad de Ciencias de la Universidad de Alicante queremos potenciar las competencias transversales de los estudiantes organizando algunos seminarios-cursos-charlas que les puedan ser de utilidad para su desarrollo como personas. En este sentido, en el presente curso académico organizado un curso de CONTINUA titulado: “Prepara tu Futuro Laboral: Emprendimiento y Búsqueda de Empleo”, especialmente enfocado a nuestros estudiantes de la Facultad de Ciencias de últimos cursos de Grado, con el fin de que les permita tener una serie de herramientas para la búsqueda de empleo y para potenciar el emprendimiento y que les pueda ser de utilidad a la finalización de sus estudios. Por otra parte, este curso académico se ha producido un relevo en los tutores/as PAT de algunas titulaciones que impartimos desde la Facultad de Ciencias. Para ayudarles en su comienzo como tutores/as, se han elaborado una serie de materiales para los nuevos tutores/as PAT.

En la red docente “Seguimiento del grado en Química: curso 2016-17”, formada por los coordinadores de las comisiones de semestre del grado en Química de la Facultad de Ciencias y la coordinadora del grado en Química, se ha analizado la información extraída de las reuniones periódicas (al menos dos por semestre) de las ocho comisiones de semestre (correspondientes a los cuatro cursos del grado en Química). El objetivo es conseguir una coherencia tanto en la distribución de contenidos, como en las metodologías docentes y de evaluación de las materias que componen el plan de estudios del Grado en Química de la Universidad de Alicante. Los resultados de este trabajo están permitiendo identificar posibles problemas y plantear propuestas de mejora en los sistemas de evaluación así como en la organización docente de la titulación.

Se ha creado un grupo de trabajo constituido por profesores que tienen experiencia en la supervisión de movilidad (tanto nacional como internacional) de alumnos y de profesores de la Facultad de Ciencias de la Universidad de Alicante. El objetivo de este grupo de trabajo para la investigación en docencia es valorar el grado de participación del colectivo de PDI (personal docente e investigador) en programas/actividades de movilidad. Asimismo, se pretende identificar cuáles son las principales fuentes de financiación (al margen de los programas oficiales) que favorecen la movilidad del PDI. A partir de la de la información recabada, se plantean propuestas de mejora para potenciar la movilidad de profesores e investigadores de la Facultad de Ciencias (tanto incoming como outgoing), así como para mejorar el registro de actividades de movilidad realizadas por el PDI de la Facultad en los sistemas de control oficial de movilidad de la Universidad de Alicante, ya que la movilidad real del PDI encontrada es mucho mayor que la que oficialmente se registra en el marco de programas oficiales ERASMUS+ (teaching staff) o Programa Propio para el fomento de las relaciones internacionales de la Universidad de la Alicante (PPI).

La internacionalización es uno de los objetivos principales en la educación, y la multiculturalidad y el multilingüismo dos retos importantes. El uso de las aplicaciones móviles con fines educativos ha adquirido gran relevancia en los últimos años gracias a un modelo comunicativo, sencillo, inter pares, en línea, ubicuo, informal, abierto y cooperativo. En este trabajo se analiza primero la motivación de los estudiantes en programas de movilidad internacional; en segundo lugar, se investiga el proceso de integración e inclusión de estudiantes internacionales; tercero, se examina la interacción entre estudiantes locales e internacionales a lo largo de un cuatrimestre. Un total de 47 estudiantes de diferentes disciplinas de Ciencias y Letras, incluyendo 35 internacionales de 14 países diferentes, fueron divididos en dos grupos, control (comunicación tradicional) y experimental (comunicación por app IM). Los resultados del experimento muestran una mejora en la percepción de su competencia intercultural y una sensación de mayor progreso en la adquisición de una segunda lengua (L2) gracias al uso de la app. La interacción entre estudiantes españoles e internacionales, tradicionalmente baja por la existencia de grupos primarios, se incrementa gracias a la comunicación por medio de la app.