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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.