https://hdl.handle.net/2072/478813 2026-04-10T01:41:23Z 2026-04-10T01:41:23Z Ilieva, Sonia Petkov, Nikolay Gargallo Gómez, Raimundo Novakov, Christo Ragelow, Miroslav Todorova, Nadezhda Vasilev, Aleksey Chesmedzhieva, Diana https://hdl.handle.net/2445/222206 2025-11-19T19:22:53Z 2025-07-14T11:59:58Z

Bioaggregachromism of Asymmetric Monomethine CyanineDyes as Noncovalent Binders for Nucleic Acids Ilieva, Sonia; Petkov, Nikolay; Gargallo Gómez, Raimundo; Novakov, Christo; Ragelow, Miroslav; Todorova, Nadezhda; Vasilev, Aleksey; Chesmedzhieva, Diana Two new asymmetric monomethine cyanine dyes, featuring dimethoxy quinoliniumor methyl quinolinium end groups and benzothiazole or methyl benzothiazole endgroups were synthesized. The chemical structures of the two dyes—(E)-6,7-dimethoxy-1-methyl-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium iodide (3a) and(E)-4-((3,5-dimethylbenzo[d]thiazol-2(3H)-ylidene)methyl)-1,2-dimethylquinolin-1-ium iodide(3b)—were confirmed through NMR spectroscopy and MALDI-TOF mass spectrometry.A new methodology was developed to study monocationic dyes in the absence of amatrix and cationizing compounds in MALDI-TOF mass experiments. The newly synthesizeddyes contain hydrophobic functional groups attached to the chromophore, enhancingtheir affinity for the hydrophobic regions of nucleic acids within the biological matrix. Thedyes’ photophysical properties were investigated in aqueous solutions and DMSO, as wellas in the presence of nucleic acids. The dyes exhibit notable aggregachromism in both pureaqueous and buffered solutions. The observed aggregation phenomena were further elucidatedusing computational methods. Fluorescence titration experiments revealed that uponcontact with nucleic acids, the dyes exhibit bioaggregachromism–aggregachromism on thesurfaces of the respective biomolecular matrix (RNA or DNA). This bioaggregachromismwas further confirmed by CD spectroscopy. Given the pronounced aggregachromismdetected, we conclude that the dyes investigated in this study are highly suitable for useas fluorogenic probes in biomolecular recognition techniques. The unique absorption andfluorescence spectra of these dyes make them promising fluorogenic markers for variousbioanalytical methods related to biomolecular recognition.

2025-07-14T11:59:58Z Fuguet i Jordà, Elisabet Amézqueta, Susana Guiteras, Jacinto López, José Fermin Rigol Parera, Anna Benavente Moreno, Fernando J. (Julián) https://hdl.handle.net/2445/218283 2025-02-03T07:30:08Z 2025-01-30T18:42:33Z

Mejora del aprendizaje en química analítica a través de actividades teórico-prácticas: acercar el laboratorio al aula y el aula al laboratorio Fuguet i Jordà, Elisabet; Amézqueta, Susana; Guiteras, Jacinto; López, José Fermin; Rigol Parera, Anna; Benavente Moreno, Fernando J. (Julián) Un problema recurrente en los estudios de Química es la dificultad que presenta el estudiantado para relacionar los conceptos teóricos con las aplicaciones prácticas y viceversa. En este trabajo se muestra el desarrollo de dos actividades de Química Analítica básica, dirigidas a una asignatura teórica y a otra práctica, con la finalidad de interrelacionar sus conocimientos y mejorar los aprendizajes. En la asignatura teórica se ha introducido una sesión de laboratorio demostrativa que da pie a una actividad que se trabaja simultáneamente a las explicaciones teóricas del profesor sobre equilibrios en disolución. En la asignatura práctica se ha profundizado en los conceptos teóricos de una valoración potenciométrica a partir de la reproducción del experimento con un simulador. En ambos casos las valoraciones, tanto por parte del profesorado como del alumnado, han sido altamente positivas y se ha constatado que ambas actividades cumplen el propósito para el cual fueron diseñadas.

2025-01-30T18:42:33Z Hermassi, H. Granados i Juan, Mercè Valderrama, C, Ayora, C. Cortina Pallàs, José Luis https://hdl.handle.net/2445/207250 2024-11-26T17:25:45Z 2024-02-07T16:52:19Z

Recovery of rare earth elements from acidic mine waters by integration of a selective chelating ion-exchanger and a solvent impregnated resin Hermassi, H.; Granados i Juan, Mercè; Valderrama, C,; Ayora, C.; Cortina Pallàs, José Luis A polymeric ion-exchange resin, incorporating methyl-amino-phosphonic (TP260) functionalities, and a solvent impregnated resin (SIR) incorporating tri-methylpentylphosphinic acid (TP272), were evaluated for the selective separation of Rare Earth Elements (REE) from Transition (TE), post -Transition (PTE), and Alkaline Earth (AE) Elements in acidic mine waters (AMW). The influence of the functional groups nature and the acidity dependence were studied and their effects on efficiencies for REE removal and separation from TE/PTE were analysed Both resins provided good separation factors of REE from TE/PTE by acidity control of the treated effluent once Fe(III), the major component in AMW, had been removed by precipitation. The TP272 resin, containing tri-methylpentylphosphinic acid (Cyanex 272) onto the polymeric network, showed higher affinity towards Heavy REE (HRRE) than for Light REE (LRRE) by acidity control (pH > 4). Higher pre-concentration factors were achieved for TP272 impregnated resin (e.g., 20–30) in comparison with the TP260 phosphonic resin (2−5), as the pH extraction window is in the moderate pH region (1−5). The integration in series of both resins could be used to separate and recover HREE and LREE from TE/PTE from AMW generated concentrates could be used to recover REE as secondary resources for the clean energy technology industry.

2024-02-07T16:52:19Z Fabregat-Palau, Joel Rigol Parera, Anna Yu, Zhiqiang Vidal Espinar, Miquel https://hdl.handle.net/2445/206281 2024-11-26T17:25:37Z 2024-01-24T18:03:32Z

Using a batch test to derive sorption data of fluoroquinolone antibiotics in humic acids Fabregat-Palau, Joel; Rigol Parera, Anna; Yu, Zhiqiang; Vidal Espinar, Miquel Fluoroquinolone antibiotics (FQs) are of concern due to their disrupting effects on environmental bacterial communities. Evaluating FQ sorption by soil components is important to understand their interaction with soils and to address their environmental (bio)availability. However, data in soil organic components, especially humic acids, are scarce. Batch experiments following OECD guidelines are suitable for testing the sorption of pollutants in solid matrices. Here, we applied this methodology, with specific changes in the experimental setup, to derive sorption data and to identify the factors affecting sorption of four common FQs in seven humic acids with contrasting properties. The effect of shaking time, pH, calcium concentration in solution and dissolved organic carbon (DOC) content on the quantification of the solid-liquid distribution coefficient (Kd) of norfloxacin in three reference humic acids was evaluated. Sorption reversibility and sorption analogy of four FQs were additionally assessed in these three reference materials, whereas the effect of initial norfloxacin concentration was evaluated in the overall set of seven humic acids. Sorption was fast, strong, non-linear, irreversible and affected by changes in the pH and calcium levels in solution. The bell-shaped sorption trend at varying pH values confirmed the key role of FQ speciation in sorption and the high Kd values indicated a positive effect of soil organic matter components on FQ sorption in bulk soils at environmentally relevant pH values. •Relevant factors affecting sorption of pollutants in environmental matrices must be considered to derive Kd values with low variability and high representativeness. •In this article we modify the experimental conditions of standard batch tests to identify the factors that affect the sorption of FQs in humic acids. •The methodological approach followed can be extrapolated to the evaluation of other combinations of pollutant and environmental matrix.

2024-01-24T18:03:32Z