Multicomponent Hydrogen-bonded Macrocyclic Assemblies from a DNA Base Toolkit

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgánica. Fecha de lectura: 14-07-201

Rapid Magnetic Dispersive solid phase extraction to preconcentration/determination of Cd and Pb in aqueous samples

A new magnetic dispersive solid phase extraction (MDSPE) method and graphite furnace atomic absorption spectrometry (GFAAS) have been combined for the analysis of Cd and Pb in environmental samples. For the preconcentration, a shell structured Fe3O4@graphene oxide nanospheres was synthetized and characterized. The material was suspended in the ionic liquid 1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4], the obtained stable colloidal suspension is named ferrofluid. GO presents excellent adsorbent properties for organic species due to the presence of the electronic π system. For this reason, the organic ligand [1,5-bis-(2-dipyridyl) methylene] thiocarbonohydrazide (DPTH) was used in order to form organic complexes of Cd and Pb. Once the DPTH ligand has been added to sample, the ferrofluid was injected and finely dispersed in the sample solution in order to extract the formed chelates. The complete adsorption of the chelates took place within few seconds then, the solid was separated from the solution with the aid of a strong magnet. Cd and Pb ions were desorbed from the material with 1 mL of acid nitric 5% solution and quantified by GFAAS. All experimental and instrumental variables were optimized. The analytical performances of the optimized method were: EF (Enrichment factor): 200 with LODs (detection limit): 0.005 and 0.004 µg L-1 and LOQs (determination limit): 0.017 and 0.013 µg L-1, for Cd and Pb, respectively. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be < 5%. The accuracy of the proposed method was verified using certified reference materials (SLRS-5, SPS-SW2, and BCR-723) and by determining the analyte content in spiked aqueous samples. Sea waters and tap water samples collected from Málaga (Spain) were also analysed. The determined values were in good agreement with the certified values and the recoveries for the spiked samples were around 100% in all cases.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Molecular Nitrides with Titanium and Group 13-15 Elements

MINISTERIO DE EDUCACIÓN Y CIENCIA, COMUNIDAD DE MADRID, UNIVERSIDAD DE ALCAL

Solid sampling determination of ZnO nanoparticles in eyeshadows by graphite furnace atomic absorption spectrometry

The application of nanoparticles (NPs) in science and technology is a fast growing field. Therefore, reliable and straightforward analytical methods are required for their fast determination in different types of samples. In this work, a method that enables the determination of the average size of ZnO NPs, besides their concentration, discriminating them from ionic zinc, has been optimized. The method is based on solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry (SS-HR-CS-GFAAS), and has been applied to determination and characterization of ZnO NPs in cosmetic samples. Recently, graphite furnace atomic absorption spectrometry has been introduced as a new tool to determine the size of nanoparticles by evaluation of the following parameters: atomization delay (tad) and atomization rate (kat). In this work both parameters (besides peak area) have been obtained from absorbance signals for a line of Zn with low sensitivity. Two multiple response surface designs have been used in order to optimize the adequate furnace program to achieve our aims. All the optimization experiments were performed using baby´s skin irritation protective cream. The optimized furnace program is shown in Table 1. Table 1. Optimized furnace program The size calibrations were performed against solid (powered) ZnO standards, from 50-nm to 500-nm sized nanoparticles. The correlation coefficients (R value) of the linear calibration were not worse than 0.9982. The optimized method was tested in other types of cosmetic samples such as eyeshadow samples with good results. The determination of the MNPs’ size was validated by transmission electron microscopy (TEM) and the Zn concentration in the solid samples was validated by atomic fluorescence spectroscopy (AFS). Acknowledgements (optional) [Garamond font, 10 points] The authors would like to thank Plan propio “Proyecto Puente” de la Universidad de Málaga for financial support of this work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Semiautomatic method for the ultra-trace arsenic speciation in environmental and biological samples via magnetic solid phase extraction prior to HPLC-ICP-MS determination

A novel magnetic functionalized material based on graphene oxide and magnetic nanoparticles (MGO) was used to develop a magnetic solid phase extraction method (MSPE) to enrich both, inorganic and organic arsenic species in environmental waters and biological samples. An automatic flow injection (FI) system was used to preconcentrate the arsenic species simultaneously, while the ultra-trace separation and determination of arsenobetaine (AsBet), cacodylate, AsIII and AsV species were achieved by high performance liquid chromatog raphy combined with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was introduced in the FI system where the MSPE was performed, then 1 mL of eluent was collected in a chromatographic vial, which was introduced in the autosampler of HPLC-ICP-MS. Therefore, preconcentration and separation/deter mination processes were automatic and conducted separately. To the best of our knowledge, this is the first method combining an automatic MSPE with HPLC-ICP-MS for arsenic speciation, using a magnetic nanomaterial based on MGO for automatic MSPE. Under the optimized conditions, the LODs for the arsenic species were 3.8 ng L− 1 AsBet, 0.5 ng L− 1 cacodylate, 1.1 ng L− 1 AsIII and 0.2 ng L− 1 AsV with RSDs <5%. The developed method was validated by analyzing Certified Reference Materials for total As concentration (fortified lake water TMDA 64.3 and seawater CASS-6 NRC) and also by recovery analysis of the arsenic species in urine, well-water and seawater samples collected in Malaga. ´ The developed method has shown promise for routine monitoring of arsenic species in environmental waters and biological fluids.This work has been partially supported by the University of Malaga (Proyecto Puente UMA), FEDER funds, Junta de Andalucia, Project UMA18FEDERJA060 and the Spanish Ministerio de Ciencia y Tecnologia (fellowship FPU18/05371). Funding for open access charge: Universidad de Málaga / CBU

Rapid magnetic microextraction to preconcentrate and determinate cadmium from environmental samples

A novel and greener ultrasonically assisted/modified cloud point extraction procedure for the preconcentration and extraction of trace cadmium from environmental samples was developed. The sorbent material was fabricated by scattering of magnetic iron nanoparticles (MNPs) over graphene oxide (GO) to obtain magnetic graphene oxide (MGO). The material was suspended in the ionic liquid 1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4]. The obtained stable colloidal suspension is named ferrofluid. GO presents excellent adsorbent properties for organic species due to the presence of the electronic π system. For this reason, the organic ligand [1,5-bis-(2-dipyridyl) methylene] thiocarbonohydrazide (DPTH) was used in order to form an organic complex of Cd. Once the DPTH ligand has been added to sample, the ferrofluid was injected and finely dispersed in the sample solution in order to extract the formed chelate as shown in Fig. 1. The complete adsorption of the quelate took place within few seconds, after that the solid was separated from the solution with the aid of a strong magnet. Cadmium ions were desorbed from the material with 1 mL of 5% acid nitric solution and quantified by electrothermal atomic absorption spectrometry (ETAAS). The main parameters affecting the extraction and the furnace program were optimized using one-at-time method. The analytical performance under optimum conditions are the following: LOD: 0.005 µg/L, LOQ: 0.017 µg/L. Linear calibration: 0-0.25 µg/L and EF: 200. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be < 5% (1.3%). The performance of the proposed procedure was checked by applying to certified reference material and spiking standard in real samplesUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Obesity-related glomerulopathy: Current approaches and future perspectives

Obesity-related glomerulopathy (ORG) is a silent comorbidity which is increasing inincidence as the obesity epidemic escalates. ORG is associated with serious healthconsequences including chronic kidney disease, end-stage renal disease (ESRD), andincreased mortality. Although the pathogenic mechanisms involved in the develop-ment of ORG are not fully understood, glomerular hemodynamic changes, renin-angiotensin-aldosterone system (RAAS) overactivation, insulin-resistance, inflamma-tion and ectopic lipid accumulation seem to play a major role. Despite albuminuriabeing commonly used for the non-invasive evaluation of ORG, promising biomarkersof early kidney injury that are emerging, as well as new approaches with proteomicsand metabolomics, might permit an earlier diagnosis of this disease. In addition, theassessment of ectopic kidney fat by renal imaging could be a useful tool to detectand evaluate the progression of ORG. Weight loss interventions appear to be effec-tive in ORG, although large-scale trials are needed. RAAS blockade has a ren-oprotective effect in patients with ORG, but even so, a significant proportion ofpatients with ORG will eventually progress to ESRD despite therapeutic efforts. It isnoteworthy that certain antidiabetic agents such as sodium-glucose cotransporter2 inhibitors (SGLT2i) or glucagon-like peptide-1 receptor agonists (GLP-1 RAs) couldbe useful in the treatment of ORG through different pleiotropic effects. In this article,we review current approaches and future perspectives in the care and treatmentof ORGInstitute of Health“Carlos III”(ISCIII), Grant/Award Numbers: JR 19/00054, CM 17/00169,PI20/01559; Funding for open access charge: Universidad de Málaga / CBU

High-fidelity noncovalent synthesis of hydrogen-bonded macrocyclic assemblies

This is the accepted version of the following article: Angewandte Chemie International Edition 54.23 (2015): 6780-6784, which has been published in final form at http://dx.doi.org/10.1002/anie.201501321A hydrogen-bonded cyclic tetramer is assembled with remarkably high effective molarities from a properly designed dinucleoside monomer. This self-assembled species exhibits an impressive thermodynamic and kinetic stability and is formed with high fidelities within a broad concentration rangeFunding from MINECO (CTQ2011-23659) and the E.U. (ERC-Starting Grant 279548) is gratefully acknowledge

Magnetic graphene oxide as a valuable material for the speciation of trace elements

Magnetic solid phase extraction (MSPE) has been explored for the application in preconcentration processes to achieve highly sensible analytical methods. Attending to the different magnetic adsorbent materials used in this field, functionalized magnetic graphene oxide (MGO) has proven to be effective for selective analysis and speciation of metals, metalloids, and derivatives in combination with several analytical techniques. Despite the increasing number of articles on speciation of trace elements using functionalized MGO as solid phase adsorbent, there are no dedicated reviews that cover the application of this novel nanomaterial, being this work pioneer in this area. This article provides a comprehensive review of the relevant literature related to the speciation of Al, Cr, As, Se, Ag, Cd, Hg, Tl and Pb, with special focus on species determined, toxicity, MGO functionalization, analytical performance, and applications, mainly to environmental and food samples. Finally, future challenges and trends related to this topic are shown.This work has been partially supported by the University of Malaga (I Plan Propio de Investigación y Transferencia, Proyecto Puente UMA and fellowship A.2.-2021 predoctoral contracts), FEDER funds, Junta de Andalucia, Project UMA18-FEDERJA-060 and the Spanish Ministerio de Ciencia y Tecnologia (fellowship FPU18/05371). Funding for open access charge: Universidad de Málaga / CBUA

Molecular Nitrides with Titanium and Rare-Earth Metals

A series of titanium-group 3/lanthanide metal complexes have been prepared by reaction of [{Ti(eta(5)-C5Me5)(mu-NH)}(3)(mu(3)-N)] (1) with halide, triflate, or amido derivatives of the rare-earth metals. Treatment of 1 with metal halide complexes [MCl3(thf)(n)] or metal trifluoromethanesulfonate derivatives [M(O3SCF3)(3)] at room temperature affords the cube-type adducts [X3M{(mu(3)-NH)(3)Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)}] (X = Cl, M = Sc (2), Y (3), La (4), Sm (5), Er (6), Lu (7); X = OTf, M = Y (8), Sm (9), Er (10)). Treatment of yttrium (3) and lanthanum (4) halide complexes with 3 equiv of lithium 2,6-dimethylphenoxido [LiOAr] produces the aryloxido complexes [(ArO)(3)M{(mu(3)-NH)(3)Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)}] (M = Y (11), La (12)). Complex 1 reacts with 0.5 equiv of rare-earth bis(trimethylsilyl)amido derivatives [M{N(SiMe3)(2)}(3)] in toluene at 85-180 degrees C to afford the corner-shared double-cube nitrido compounds [M(mu(3)-N)(3)(mu(3)-NH)(3){Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)}(2)] (M = Sc (13), Y (14), La (15), Sm (16), Eu (17), Er (18), Lu (19)) via NH(SiMe3)(2) elimination. A single-cube intermediate [{(Me3Si)(2)N}Sc{(mu(3)-N)(2)(mu(3)-NH)Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)}] (20) was obtained by the treatment of 1 with 1 equiv of the scandium bis(trimethylsilyl)amido derivative [Sc{N(SiMe3)(2)}(3)]. The X-ray crystal structures of 2, 7, 11, 14, 15, and 19 have been determined. The thermal decomposition in the solid state of double-cube nitrido complexes 14, 15, and 18 has been investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements, as well as by pyrolysis experiments at 1100 degrees C under different atmospheres (Ar, H-2/N-2, NH3) for the yttrium complex 14.Ministerio de Educación y Ciencia de España, Comunidad de Madrid, Universidad de Alcal