The importance of multidimensionality in the tunneling effect.
Authorship
D.C.A.G.
Double bachelor degree in Physics and Chemistry
D.C.A.G.
Double bachelor degree in Physics and Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
This work consists of an in-depth study of the crucial role played by quantum tunneling in chemical kinetics, focusing on two systems that are particularly sensitive to this phenomenon: the tautomerizations of Thiouracils and the formation of Vitamin D. By means of ab initio simulations, various theoretical models are studied to calculate reaction rate constants using both one-dimensional and multidimensional formulations. The canonical variational transition state theory will be used, comparing different methods to compute the quantum contributions to the rate constant, including one-dimensional models such as Eckart’s, historically relevant but poorly aligned with experimental data, and multidimensional models, where zero curvature tunneling and small curvature tunneling will be analyzed. By comparing the results obtained with the different methods, the study aims to identify which model best represents the real kinetic behavior of the system, thereby determining the importance of taking the multidimensional nature of these into account. This study aims to improve the prediction of reaction rates, along with a deeper understanding of the molecular mechanisms involved, offering an essential approach for various fields of research.
This work consists of an in-depth study of the crucial role played by quantum tunneling in chemical kinetics, focusing on two systems that are particularly sensitive to this phenomenon: the tautomerizations of Thiouracils and the formation of Vitamin D. By means of ab initio simulations, various theoretical models are studied to calculate reaction rate constants using both one-dimensional and multidimensional formulations. The canonical variational transition state theory will be used, comparing different methods to compute the quantum contributions to the rate constant, including one-dimensional models such as Eckart’s, historically relevant but poorly aligned with experimental data, and multidimensional models, where zero curvature tunneling and small curvature tunneling will be analyzed. By comparing the results obtained with the different methods, the study aims to identify which model best represents the real kinetic behavior of the system, thereby determining the importance of taking the multidimensional nature of these into account. This study aims to improve the prediction of reaction rates, along with a deeper understanding of the molecular mechanisms involved, offering an essential approach for various fields of research.
Direction
FERRO COSTAS, DAVID (Tutorships)
FERRO COSTAS, DAVID (Tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Topotactic oxygen exchange in transition metal oxides via solid electrolytes
Authorship
C.A.P.
Bachelor of Chemistry
C.A.P.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
This research work focuses on the study of the physicochemical properties of ceramic oxide films with the composition La1-xSrxFeO3 as well as the structural changes induced by topotactic O2- exchange, driving the material through different metastable phases. The compounds under study were prepared using the sol-gel method, and after several high-temperature treatments, targets were obtained. These targets were epitaxially grown on LSAT substrates via pulsed laser deposition (PLD), in the form of thin films. This growth was carried out in a stable oxygen atmosphere in order to obtain films with a composition such as SrFeOx, where x takes an approximate value of x=2.5. The resistivity of each film was measured. Following this, each sample was also grown (again by PLD) on a YSZ substrate, incorporating a thin intermediate layer of CeO2. Then, O2- ions were injected through one side of the film by applying a known negative voltage, inducing the deintercalation of oxygen from O3 to O3-x. This results in a structural transformation (from perovskite to brownmillerite, or vice versa if O2- is inserted using a positive potential difference), along with changes in electrical conductivity and optical properties. Structural and compositional characterization was carried out using X-ray diffraction (XRD), X-ray reflectivity (XRR), and scanning electron microscopy (SEM). Furthermore, the variability of these properties, as well as the phase evolution and electrical conductivity during oxidation and reduction, are correlated with the electronic structure and with the relative energy positions of the oxygen and metal bands.
This research work focuses on the study of the physicochemical properties of ceramic oxide films with the composition La1-xSrxFeO3 as well as the structural changes induced by topotactic O2- exchange, driving the material through different metastable phases. The compounds under study were prepared using the sol-gel method, and after several high-temperature treatments, targets were obtained. These targets were epitaxially grown on LSAT substrates via pulsed laser deposition (PLD), in the form of thin films. This growth was carried out in a stable oxygen atmosphere in order to obtain films with a composition such as SrFeOx, where x takes an approximate value of x=2.5. The resistivity of each film was measured. Following this, each sample was also grown (again by PLD) on a YSZ substrate, incorporating a thin intermediate layer of CeO2. Then, O2- ions were injected through one side of the film by applying a known negative voltage, inducing the deintercalation of oxygen from O3 to O3-x. This results in a structural transformation (from perovskite to brownmillerite, or vice versa if O2- is inserted using a positive potential difference), along with changes in electrical conductivity and optical properties. Structural and compositional characterization was carried out using X-ray diffraction (XRD), X-ray reflectivity (XRR), and scanning electron microscopy (SEM). Furthermore, the variability of these properties, as well as the phase evolution and electrical conductivity during oxidation and reduction, are correlated with the electronic structure and with the relative energy positions of the oxygen and metal bands.
Direction
RIVADULLA FERNANDEZ, JOSE FRANCISCO (Tutorships)
RIVADULLA FERNANDEZ, JOSE FRANCISCO (Tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Chaotropic effect in the synthesis of nanoparticles
Authorship
A.D.S.
Bachelor of Chemistry
A.D.S.
Bachelor of Chemistry
Defense date
09.18.2025 16:30
09.18.2025 16:30
Summary
This thesis, presented as a final degree project in Chemistry by USC, aims to study the chaotropic effect and its potential application in the synthesis of nanoparticles. The starting point is a theoretical and historical introduction in which key concepts such as the Hofmeister series, the relationship between chaotropicity and hydrophobicity are defined, highlighting similarities and differences, and the concept of superchaotropicity is also introduced. On the other hand, the general context of nanoparticles is presented, highlighting their relevance and most notable properties. Its synthesis process is also described and the use of chaotropic agents as an innovative tool is presented. In the discussion part, we will first focus on exploring how different types of chaotropic ions influence important medium parameters such as solvent, concentration, pH, temperature, and viscosity. Subsequently, we will analyze in detail the reagents and media necessary for the synthesis of nanoparticles, as well as the role that chaotropic and superchaotropic ions play within this process. Therefore, the use of chaotropic agents could pave the way for more environmentally friendly synthesis strategies by reducing the need for conventional stabilizers or reducers, which are often more toxic or polluting. This approach not only contributes to the development of greener and more sustainable chemistry but also improves the functionality and stability of the resulting nanomaterials.
This thesis, presented as a final degree project in Chemistry by USC, aims to study the chaotropic effect and its potential application in the synthesis of nanoparticles. The starting point is a theoretical and historical introduction in which key concepts such as the Hofmeister series, the relationship between chaotropicity and hydrophobicity are defined, highlighting similarities and differences, and the concept of superchaotropicity is also introduced. On the other hand, the general context of nanoparticles is presented, highlighting their relevance and most notable properties. Its synthesis process is also described and the use of chaotropic agents as an innovative tool is presented. In the discussion part, we will first focus on exploring how different types of chaotropic ions influence important medium parameters such as solvent, concentration, pH, temperature, and viscosity. Subsequently, we will analyze in detail the reagents and media necessary for the synthesis of nanoparticles, as well as the role that chaotropic and superchaotropic ions play within this process. Therefore, the use of chaotropic agents could pave the way for more environmentally friendly synthesis strategies by reducing the need for conventional stabilizers or reducers, which are often more toxic or polluting. This approach not only contributes to the development of greener and more sustainable chemistry but also improves the functionality and stability of the resulting nanomaterials.
Direction
GIMENEZ LOPEZ, MARIA DEL CARMEN (Tutorships)
VILA FUNGUEIRIÑO, JOSE MANUEL (Co-tutorships)
GIMENEZ LOPEZ, MARIA DEL CARMEN (Tutorships)
VILA FUNGUEIRIÑO, JOSE MANUEL (Co-tutorships)
Court
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
The saffron: composition, properties and potencial applications
Authorship
A.F.C.
Bachelor of Chemistry
A.F.C.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Crocus sativus, commonly known as saffron plant, is highly valued globally since ancient times, not only for the organoleptic properties of the spice derived from its dried stigmas, characteristic for its intensity of color, bitter taste and unique aroma; but also because it contains a high concentration of bioactive compounds that give it unique properties with a large repertoire of applications and benefits for human health. These applications range from the most traditional use, as in food seasoning or cosmetics, to the most pioneering, still under development, in various therapies in medicine and pharmacy, focused on its power of action in the central nervous system and cellular protection. It is not possible to understand their multifaceted action capacity without studying their phytochemical richness. Among the more than 150 biocompounds identified, the apocarotenoids stand out, where crocetin, crocin, picrocrocin and safranal play a central role in the identifying properties of saffron. Also of great importance are the flavonoids, which are found in great variety and complement the antioxidant and anti-inflammatory activity, the main properties of saffron, from which many of the beneficial effects under study are cemented and potentiated. This paper focuses on scientific studies carried out in recent years in order to carry out a review, gathering as much information as possible and providing an overview of these aspects as a basis for future studies.
Crocus sativus, commonly known as saffron plant, is highly valued globally since ancient times, not only for the organoleptic properties of the spice derived from its dried stigmas, characteristic for its intensity of color, bitter taste and unique aroma; but also because it contains a high concentration of bioactive compounds that give it unique properties with a large repertoire of applications and benefits for human health. These applications range from the most traditional use, as in food seasoning or cosmetics, to the most pioneering, still under development, in various therapies in medicine and pharmacy, focused on its power of action in the central nervous system and cellular protection. It is not possible to understand their multifaceted action capacity without studying their phytochemical richness. Among the more than 150 biocompounds identified, the apocarotenoids stand out, where crocetin, crocin, picrocrocin and safranal play a central role in the identifying properties of saffron. Also of great importance are the flavonoids, which are found in great variety and complement the antioxidant and anti-inflammatory activity, the main properties of saffron, from which many of the beneficial effects under study are cemented and potentiated. This paper focuses on scientific studies carried out in recent years in order to carry out a review, gathering as much information as possible and providing an overview of these aspects as a basis for future studies.
Direction
BUJAN NUÑEZ, MARIA CARMEN (Tutorships)
BUJAN NUÑEZ, MARIA CARMEN (Tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
Microplastic Analysis in Environmental Samples Using Spectroscopic Techniques
Authorship
N.F.G.
Bachelor of Chemistry
N.F.G.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Microplastics (MPs) are an increasingly important contaminant to consider, as their production is rising and, consequently, more MPs are being released into the environment, with growing presence in both air and oceans. This means that humans may inhale or ingest them, potentially leading to respiratory and digestive problems. Due to these impacts, their analysis in environmental samples is of vital importance. This study aimed to identify an effective method for analyzing MPs in sewage sludge samples. Several techniques were applied, including optical microscopy, Raman spectroscopy, density separation, and chemical digestion. One of the major problems in this type of sample is the high amount of organic matter, which affects the results of both optical microscopy and Raman spectroscopy. Therefore, the digestion step is crucial. Different methods were compared, such as the use of Fenton's reagent as a catalyst and the use of successive digestions, to evaluate which is the most efficient.
Microplastics (MPs) are an increasingly important contaminant to consider, as their production is rising and, consequently, more MPs are being released into the environment, with growing presence in both air and oceans. This means that humans may inhale or ingest them, potentially leading to respiratory and digestive problems. Due to these impacts, their analysis in environmental samples is of vital importance. This study aimed to identify an effective method for analyzing MPs in sewage sludge samples. Several techniques were applied, including optical microscopy, Raman spectroscopy, density separation, and chemical digestion. One of the major problems in this type of sample is the high amount of organic matter, which affects the results of both optical microscopy and Raman spectroscopy. Therefore, the digestion step is crucial. Different methods were compared, such as the use of Fenton's reagent as a catalyst and the use of successive digestions, to evaluate which is the most efficient.
Direction
ABOAL SOMOZA, MANUEL (Tutorships)
PEÑA VAZQUEZ, ELENA MARIA (Co-tutorships)
ABOAL SOMOZA, MANUEL (Tutorships)
PEÑA VAZQUEZ, ELENA MARIA (Co-tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Procedure to obtain carbocyclic beta aminoacids in the multigram scale. A bibliographic search
Authorship
A.G.T.
Bachelor of Chemistry
A.G.T.
Bachelor of Chemistry
Defense date
09.18.2025 16:30
09.18.2025 16:30
Summary
This work consists of a bibliographic study of two carbocyclic beta amino acids, ACHC (2-aminocyclohexane-1-carboxylic acid) and ACPC (2-aminocyclopentane-1-carboxylic acid). The ultimate goal is to find the most efficient and economical synthesis methods. Throughout this work, several searches were conducted in various databases, primarily SciFinder. The primary objective was to identify derivatives of these molecules that could serve as synthetic precursors or as intermediates in synthetic routes. These searches explored various structural modifications, both in the carboxylic acid and amine functional groups, and in both simultaneously. The filters used and the main information obtained from the bibliographies are described for each search. Special attention was paid to the three currently most convenient protecting groups for peptide synthesis: Cbz, Boc, and Fmoc. This paper briefly describes some potential applications of beta amino acids, highlighting their role in foldamer formation and their use in fields such as biomedicine, where they can act as antimicrobial, anticancer, or neuroprotective agents. Finally, it presents some synthetic routes to obtain these compounds, with particular emphasis on those that yield products with trans stereochemistry in enantiopure form.
This work consists of a bibliographic study of two carbocyclic beta amino acids, ACHC (2-aminocyclohexane-1-carboxylic acid) and ACPC (2-aminocyclopentane-1-carboxylic acid). The ultimate goal is to find the most efficient and economical synthesis methods. Throughout this work, several searches were conducted in various databases, primarily SciFinder. The primary objective was to identify derivatives of these molecules that could serve as synthetic precursors or as intermediates in synthetic routes. These searches explored various structural modifications, both in the carboxylic acid and amine functional groups, and in both simultaneously. The filters used and the main information obtained from the bibliographies are described for each search. Special attention was paid to the three currently most convenient protecting groups for peptide synthesis: Cbz, Boc, and Fmoc. This paper briefly describes some potential applications of beta amino acids, highlighting their role in foldamer formation and their use in fields such as biomedicine, where they can act as antimicrobial, anticancer, or neuroprotective agents. Finally, it presents some synthetic routes to obtain these compounds, with particular emphasis on those that yield products with trans stereochemistry in enantiopure form.
Direction
SANCHEZ PEDREGAL, VICTOR MANUEL (Tutorships)
SANCHEZ PEDREGAL, VICTOR MANUEL (Tutorships)
Court
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
Ecophysiological aspects and impacts of the invasive plant Tradescantia fluminensis: A review paper
Authorship
M.G.V.
Double bachelor degree in Chemistry and Biology
M.G.V.
Double bachelor degree in Chemistry and Biology
Defense date
09.11.2025 10:00
09.11.2025 10:00
Summary
Tradescantia fluminensis, commonly known as wandering Jew or inch plant, is a member of the Commelinaceae family and originates from South America. It is a perennial, herbaceous species with highly branched stems, reaching heights between 30 and 60 centimeters. It has been introduced to almost every country in the world for ornamental purposes and remains very common in gardening today. Due to this artificial geographic expansion, it has become problematic in many countries because of its invasive nature and demographic expansion, growing very rapidly in shady and moist environments. This species primarily establishes itself in riparian forests and poses a significant threat to these habitats in places like Australia, New Zealand, and the United States, as well as in Mediterranean European countries such as Portugal, Italy, and Spain. In Spain, Galicia is one of the most affected areas, along with the Cantabrian and Mediterranean coasts and the Canary Islands. This paper presents a literature review of documents referring to T. fluminensis, aiming to select the most relevant and, when possible, the most recent information regarding its impact on biodiversity, control or eradication methods that can be applied, and the potential benefits that can be obtained from this species. The reviewed works highlight that T. fluminensis affects both flora and fauna, reducing the diversity and cover of native vegetation and altering the abundance and diversity of invertebrates. From a management perspective, some authors emphasize that biological control methods are the most advisable, although herbicides such as triclopyr can also be used. Regarding the potential uses of the plant, paper production and the extraction of antioxidant compounds are considered, although further exploration of management strategies is needed that focus on making use of plant waste generated through mechanical control methods such as manual removal.
Tradescantia fluminensis, commonly known as wandering Jew or inch plant, is a member of the Commelinaceae family and originates from South America. It is a perennial, herbaceous species with highly branched stems, reaching heights between 30 and 60 centimeters. It has been introduced to almost every country in the world for ornamental purposes and remains very common in gardening today. Due to this artificial geographic expansion, it has become problematic in many countries because of its invasive nature and demographic expansion, growing very rapidly in shady and moist environments. This species primarily establishes itself in riparian forests and poses a significant threat to these habitats in places like Australia, New Zealand, and the United States, as well as in Mediterranean European countries such as Portugal, Italy, and Spain. In Spain, Galicia is one of the most affected areas, along with the Cantabrian and Mediterranean coasts and the Canary Islands. This paper presents a literature review of documents referring to T. fluminensis, aiming to select the most relevant and, when possible, the most recent information regarding its impact on biodiversity, control or eradication methods that can be applied, and the potential benefits that can be obtained from this species. The reviewed works highlight that T. fluminensis affects both flora and fauna, reducing the diversity and cover of native vegetation and altering the abundance and diversity of invertebrates. From a management perspective, some authors emphasize that biological control methods are the most advisable, although herbicides such as triclopyr can also be used. Regarding the potential uses of the plant, paper production and the extraction of antioxidant compounds are considered, although further exploration of management strategies is needed that focus on making use of plant waste generated through mechanical control methods such as manual removal.
Direction
RETUERTO FRANCO, JOSE CARLOS RUBÉN (Tutorships)
RODRIGUEZ PARRA, JONATAN (Co-tutorships)
RETUERTO FRANCO, JOSE CARLOS RUBÉN (Tutorships)
RODRIGUEZ PARRA, JONATAN (Co-tutorships)
Court
PRIETO LAMAS, BEATRIZ LORETO (Chairman)
BASELGA FRAGA, ANDRES (Secretary)
AMIGO VAZQUEZ, FRANCISCO JAVIER (Member)
PRIETO LAMAS, BEATRIZ LORETO (Chairman)
BASELGA FRAGA, ANDRES (Secretary)
AMIGO VAZQUEZ, FRANCISCO JAVIER (Member)
Electrochemical synthesis and structural study of metal complexes with polydentate ligands
Authorship
M.G.V.
Double bachelor degree in Chemistry and Biology
M.G.V.
Double bachelor degree in Chemistry and Biology
Defense date
09.18.2025 16:00
09.18.2025 16:00
Summary
This work describes the synthesis of cobalt, nickel, and zinc complexes with the ligand (Z)-N-isonicotinoylpicolinohydrazonamide (HLA), as well as a lead complex with the ligand (Z)-N-benzoylpicolinohydrazonamide (HLB), using an electrochemical synthesis method. This procedure has proven to be a highly effective technique, allowing the formation of complexes with high purity and an electrochemical efficiency of 0.5, which demonstrates that the metal is oxidized to M(II) in all the compounds. All complexes were characterized using the following experimental analytical techniques: elemental analysis, infrared spectroscopy, 1H and 13C nuclear magnetic resonance and X-ray diffraction.
This work describes the synthesis of cobalt, nickel, and zinc complexes with the ligand (Z)-N-isonicotinoylpicolinohydrazonamide (HLA), as well as a lead complex with the ligand (Z)-N-benzoylpicolinohydrazonamide (HLB), using an electrochemical synthesis method. This procedure has proven to be a highly effective technique, allowing the formation of complexes with high purity and an electrochemical efficiency of 0.5, which demonstrates that the metal is oxidized to M(II) in all the compounds. All complexes were characterized using the following experimental analytical techniques: elemental analysis, infrared spectroscopy, 1H and 13C nuclear magnetic resonance and X-ray diffraction.
Direction
LABISBAL VIQUEIRA, MARIA ELENA (Tutorships)
García Santos, María Isabel (Co-tutorships)
LABISBAL VIQUEIRA, MARIA ELENA (Tutorships)
García Santos, María Isabel (Co-tutorships)
Court
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
Dual HDAC and PDL1 inhibitor drugs in cancer therapy
Authorship
A.G.A.
Bachelor of Chemistry
A.G.A.
Bachelor of Chemistry
Defense date
09.18.2025 16:30
09.18.2025 16:30
Summary
The understanding of cancer and its treatment has evolved as a result of extensive scientific research. This undergraduate thesis analyzes synthetic strategies for the preparation of dual inhibitors compounds that contain two pharmacophores in their structure, capable of interacting with two different targets and modulating their activity. Of the possible targets, histone deacetylase enzymes (HDAC) and programmed death-ligand 1 (PDL1) have been chosen, as they are key in immune system evasion and tumor progression. By inhibiting these two targets, gene expression and immune evasion by tumor cells are affected, making this combination a promising therapeutic approach against cancer. After describing the characteristics of these two targets, the design, synthesis, and evaluation of two dual PDL1/HDAC inhibitors are highlighted as examples of the potential of this approach: PH3 (HDAC3/PDL1 inhibitor) and HP29 (targeting HDAC6/PDL1). Both show high antitumor efficacy, enhancing T-cell infiltration, reducing tumor growth, and inducing apoptosis. The results validate the dual inhibition strategy, highlighting it as an innovative research pathway that opens new doors in epigenetic immunotherapy, although many challenges remain to be addressed.
The understanding of cancer and its treatment has evolved as a result of extensive scientific research. This undergraduate thesis analyzes synthetic strategies for the preparation of dual inhibitors compounds that contain two pharmacophores in their structure, capable of interacting with two different targets and modulating their activity. Of the possible targets, histone deacetylase enzymes (HDAC) and programmed death-ligand 1 (PDL1) have been chosen, as they are key in immune system evasion and tumor progression. By inhibiting these two targets, gene expression and immune evasion by tumor cells are affected, making this combination a promising therapeutic approach against cancer. After describing the characteristics of these two targets, the design, synthesis, and evaluation of two dual PDL1/HDAC inhibitors are highlighted as examples of the potential of this approach: PH3 (HDAC3/PDL1 inhibitor) and HP29 (targeting HDAC6/PDL1). Both show high antitumor efficacy, enhancing T-cell infiltration, reducing tumor growth, and inducing apoptosis. The results validate the dual inhibition strategy, highlighting it as an innovative research pathway that opens new doors in epigenetic immunotherapy, although many challenges remain to be addressed.
Direction
PALEO PILLADO, MARIA RITA (Tutorships)
PALEO PILLADO, MARIA RITA (Tutorships)
Court
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
SAA RODRIGUEZ, CARLOS EUGENIO (Chairman)
SOUSA PEDRARES, ANTONIO (Secretary)
GARCIA DEIBE, ANA MARIA (Member)
Fluorescent proton transfer probes. Properties of pyranine.
Authorship
T.G.S.
Bachelor of Chemistry
T.G.S.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Proton transfer processes play a fundamental role in multiple chemical and biological processes. In particular, reactions involving this type of process in an electronically excited state are especially relevant. To analyze proton transfer in the excited state, it is effective to use fluorescent probes. In this work, the properties of 1-hydroxy-3,6,8-pyrenetrisulfonic acid (pyranine) were analyzed. For this purpose, studies were conducted in different solvents and at various acidity levels in aqueous media, in order to study the acid-base equilibrium in the both the ground and excited states. Additionally, experiments were carried out to measure the fluorescence quantum yield and fluorescence lifetime, in order to better characterize pyranine. Furthermore, base don the results obtained from the previous measurements, the radiative and non-radiative deactivation constants, as well as the molar absorption coefficient, were calculated. From this analysis, by obtaining results in highly acidic, mildly acidic and basic media, it is known that this fluorescent probe dissociates after excitation in slightly acidic environments. Moreover, the acidity constants in the ground state (pKa) and excited state (pKa*) are 7.78 and 1.93, respectively, indicating that this is a photoacid, as pKa is higher than pKa*.
Proton transfer processes play a fundamental role in multiple chemical and biological processes. In particular, reactions involving this type of process in an electronically excited state are especially relevant. To analyze proton transfer in the excited state, it is effective to use fluorescent probes. In this work, the properties of 1-hydroxy-3,6,8-pyrenetrisulfonic acid (pyranine) were analyzed. For this purpose, studies were conducted in different solvents and at various acidity levels in aqueous media, in order to study the acid-base equilibrium in the both the ground and excited states. Additionally, experiments were carried out to measure the fluorescence quantum yield and fluorescence lifetime, in order to better characterize pyranine. Furthermore, base don the results obtained from the previous measurements, the radiative and non-radiative deactivation constants, as well as the molar absorption coefficient, were calculated. From this analysis, by obtaining results in highly acidic, mildly acidic and basic media, it is known that this fluorescent probe dissociates after excitation in slightly acidic environments. Moreover, the acidity constants in the ground state (pKa) and excited state (pKa*) are 7.78 and 1.93, respectively, indicating that this is a photoacid, as pKa is higher than pKa*.
Direction
Rodríguez Prieto, María de la Flor (Tutorships)
RIOS RODRIGUEZ, MARIA DEL CARMEN (Co-tutorships)
Rodríguez Prieto, María de la Flor (Tutorships)
RIOS RODRIGUEZ, MARIA DEL CARMEN (Co-tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Design and synthesis of functionalized tetracene oligomers
Authorship
D.M.C.
Bachelor of Chemistry
D.M.C.
Bachelor of Chemistry
Defense date
09.18.2025 16:00
09.18.2025 16:00
Summary
Selectivity control in chemical reactions is a key challenge in synthetic chemistry. Recently, the research group undertaking this project in cooperation with INM Research Zürich (Switzerland) and Ratisbona University (Germany), has established that it is possible to perform unimolecular chemical reactions selectively by controlling the amplitude of an external stimulus. Specifically, starting from a defined molecule, the formed product could be selected applying an adequate voltage pulse (varying its sign and amplitude). This pioneer work was implemented using as a precursor 5,6,11,12-tetrachlorotetracene. This final degree project aims to go one step further and prepare a derivative of the previous molecule that allows a greater degree of control at the molecular level. Specifically, it focuses on the synthesis of 2-bromo-5,6,11,11-tetrachlorotetracene. In order to achieve this, two different synthetic routs have been tried. The first one is based on the direct functionalization of 5,6,11,12-tetrachlorotetracene through the C-H activation with an iridium catalyst. The second one is based on a four-step synthesis using commercial products, which allows to incorporate the bromine atom from the beginning of the synthesis. Moreover, synthesis of dimeric compounds has been tried, specifically of 1,4-bis(5,6,11,12-tetrachlorotetracen-2-yl)benzene. To this effect, a Suzuki C-C cross coupling reaction was carried out between 2-bromo-5,6,11,12-tetrachlorotetracene and 1,4-fenildiboronic acid.
Selectivity control in chemical reactions is a key challenge in synthetic chemistry. Recently, the research group undertaking this project in cooperation with INM Research Zürich (Switzerland) and Ratisbona University (Germany), has established that it is possible to perform unimolecular chemical reactions selectively by controlling the amplitude of an external stimulus. Specifically, starting from a defined molecule, the formed product could be selected applying an adequate voltage pulse (varying its sign and amplitude). This pioneer work was implemented using as a precursor 5,6,11,12-tetrachlorotetracene. This final degree project aims to go one step further and prepare a derivative of the previous molecule that allows a greater degree of control at the molecular level. Specifically, it focuses on the synthesis of 2-bromo-5,6,11,11-tetrachlorotetracene. In order to achieve this, two different synthetic routs have been tried. The first one is based on the direct functionalization of 5,6,11,12-tetrachlorotetracene through the C-H activation with an iridium catalyst. The second one is based on a four-step synthesis using commercial products, which allows to incorporate the bromine atom from the beginning of the synthesis. Moreover, synthesis of dimeric compounds has been tried, specifically of 1,4-bis(5,6,11,12-tetrachlorotetracen-2-yl)benzene. To this effect, a Suzuki C-C cross coupling reaction was carried out between 2-bromo-5,6,11,12-tetrachlorotetracene and 1,4-fenildiboronic acid.
Direction
PEÑA GIL, DIEGO (Tutorships)
Pozo Míguez, Iago (Co-tutorships)
PEÑA GIL, DIEGO (Tutorships)
Pozo Míguez, Iago (Co-tutorships)
Court
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
Design and synthesis of conjugated metal_orgánicas structures (MOFs) for electrocatalytic applications
Authorship
C.N.S.
Bachelor of Chemistry
C.N.S.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
This project has studied the production of metal_organic nanoparticles (MOFs) composed of Cu or Co cations with two types of organic ligands: MI and HITP, resulting in two types of MOFs. Furthermore, the doping process of these structures with Ni has been studied, optimizing the synthesis process in aqueous solution at room temperature and introducing activation using ultrasound and temperature. In the case of Cu3(HITP)2, nanoparticles with an orthorhombic structure were obtained with an average size of 100 nm to 120 nm depending on the synthesis process. Regarding the MI ligand, 110 nm particles were obtained, but as the presence of Ni in the sample increases, the structure of these MOFs is lost, which has been identified by the presence of Ni hydroxide impurities due to the basic pH of the solution. Functionally, the N2 adsorption study determined that Cu3(HITP)2 presents an active surface area of 277 m2/g, which gradually decreases as the degree of Ni doping increases. For the CoMI MOF (ZIF_67) the surface area increases up to 900 m2/g but the introduction of Ni in the synthesis shows a very abrupt drop in absorption (85 m2/g) consistent with the structural data and confirmed by the magnetic data. These data demonstrate that the three-dimensional structure of ZIF_67 allows a higher adsorption capacity than the 2D HITP.
This project has studied the production of metal_organic nanoparticles (MOFs) composed of Cu or Co cations with two types of organic ligands: MI and HITP, resulting in two types of MOFs. Furthermore, the doping process of these structures with Ni has been studied, optimizing the synthesis process in aqueous solution at room temperature and introducing activation using ultrasound and temperature. In the case of Cu3(HITP)2, nanoparticles with an orthorhombic structure were obtained with an average size of 100 nm to 120 nm depending on the synthesis process. Regarding the MI ligand, 110 nm particles were obtained, but as the presence of Ni in the sample increases, the structure of these MOFs is lost, which has been identified by the presence of Ni hydroxide impurities due to the basic pH of the solution. Functionally, the N2 adsorption study determined that Cu3(HITP)2 presents an active surface area of 277 m2/g, which gradually decreases as the degree of Ni doping increases. For the CoMI MOF (ZIF_67) the surface area increases up to 900 m2/g but the introduction of Ni in the synthesis shows a very abrupt drop in absorption (85 m2/g) consistent with the structural data and confirmed by the magnetic data. These data demonstrate that the three-dimensional structure of ZIF_67 allows a higher adsorption capacity than the 2D HITP.
Direction
VILA FUNGUEIRIÑO, JOSE MANUEL (Tutorships)
TABOADA ANTELO, PABLO (Co-tutorships)
VILA FUNGUEIRIÑO, JOSE MANUEL (Tutorships)
TABOADA ANTELO, PABLO (Co-tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Recovery of bioactive compounds from agri food sources using new biocompatible solvents
Authorship
I.H.P.R.
Bachelor of Chemistry
I.H.P.R.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
This work focuses on the extraction, characterization, and analysis of extracts rich in bioactive compounds from black oat, providing an overview of the total polyphenol content. The study was carried out using the matrix solid phase dispersion (MSPD) extraction technique, which employed two types of solvents: conventional organic solvents and natural deep eutectic solvents (NADES). This technique stands out to be environmentally friendly, fast, simple, and cost effective. In addition, the antioxidant activity (AA) of each extract was evaluated using the DPPH test, determining the extract concentration required to reduce DPPH absorbance by 50 (EC50). Higher antioxidant activity was shown in the extracts obtained with glycerol and ethanol (first fractions) compared to the other solvents. Individual compound characterization by ultra high performance liquid chromatography (UHPLC) coupled with quadrupole time of flight mass spectrometry (QTOFMS) revealed the presence of various classes of polyphenols, including phenolic acids, avenanthramides, and flavonoids. On the other hand, non polyphenolic compounds such as azelaic acid were also identified.
This work focuses on the extraction, characterization, and analysis of extracts rich in bioactive compounds from black oat, providing an overview of the total polyphenol content. The study was carried out using the matrix solid phase dispersion (MSPD) extraction technique, which employed two types of solvents: conventional organic solvents and natural deep eutectic solvents (NADES). This technique stands out to be environmentally friendly, fast, simple, and cost effective. In addition, the antioxidant activity (AA) of each extract was evaluated using the DPPH test, determining the extract concentration required to reduce DPPH absorbance by 50 (EC50). Higher antioxidant activity was shown in the extracts obtained with glycerol and ethanol (first fractions) compared to the other solvents. Individual compound characterization by ultra high performance liquid chromatography (UHPLC) coupled with quadrupole time of flight mass spectrometry (QTOFMS) revealed the presence of various classes of polyphenols, including phenolic acids, avenanthramides, and flavonoids. On the other hand, non polyphenolic compounds such as azelaic acid were also identified.
Direction
ALVAREZ RIVERA, GERARDO (Tutorships)
LORES AGUIN, MARTA (Co-tutorships)
ALVAREZ RIVERA, GERARDO (Tutorships)
LORES AGUIN, MARTA (Co-tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
Study of peptides with non-aromatic fluorescent emission
Authorship
A.R.F.
Bachelor of Chemistry
A.R.F.
Bachelor of Chemistry
Defense date
09.18.2025 16:00
09.18.2025 16:00
Summary
Conventionally, the phenomenon of fluorescent emission in biomolecules has been ascribed to the presence of aromatic residues, including but not limited to phenylalanine, tyrosine and tryptophan. However, recent studies have demonstrated that certain peptide sequences are capable of exhibiting luminescent emission in the absence of these chromophores. This phenomenon, which remains to be fully elucidated, is referred to as non-aromatic fluorescence (NAF). At present, there is an absence of both a consolidated theoretical model and clear guidelines for the design of non-aromatic peptide luminophores. This makes the detailed study of these systems a promising avenue to deepen the understanding of NAF mechanisms and broaden their application in fields such as biomedicine and materials science. The present work focuses on the design of a genetically encodable luminescent label by fusing the (E4K4)4 sensitizer, whose ability to induce non-aromatic fluorescence (NAF) has been demonstrated in previous studies, with the lanthanide-binding label developed by Imperiali et al. in the 2000s (Lanthanide Binding Tag, LBT), modified to remove any aromatic residues from its sequence. The primary objective of this study was to evaluate its ability to efficiently coordinate trivalent lanthanide ions (Ln+3), with a particular focus on europium (Eu+3), and to transfer energy to induce fluorescent emission. In addition to evaluating the feasibility of this material as a functional luminescent label in cellular models, the aim is to explore its potential in bioimaging applications and genetically encodable biosensors.
Conventionally, the phenomenon of fluorescent emission in biomolecules has been ascribed to the presence of aromatic residues, including but not limited to phenylalanine, tyrosine and tryptophan. However, recent studies have demonstrated that certain peptide sequences are capable of exhibiting luminescent emission in the absence of these chromophores. This phenomenon, which remains to be fully elucidated, is referred to as non-aromatic fluorescence (NAF). At present, there is an absence of both a consolidated theoretical model and clear guidelines for the design of non-aromatic peptide luminophores. This makes the detailed study of these systems a promising avenue to deepen the understanding of NAF mechanisms and broaden their application in fields such as biomedicine and materials science. The present work focuses on the design of a genetically encodable luminescent label by fusing the (E4K4)4 sensitizer, whose ability to induce non-aromatic fluorescence (NAF) has been demonstrated in previous studies, with the lanthanide-binding label developed by Imperiali et al. in the 2000s (Lanthanide Binding Tag, LBT), modified to remove any aromatic residues from its sequence. The primary objective of this study was to evaluate its ability to efficiently coordinate trivalent lanthanide ions (Ln+3), with a particular focus on europium (Eu+3), and to transfer energy to induce fluorescent emission. In addition to evaluating the feasibility of this material as a functional luminescent label in cellular models, the aim is to explore its potential in bioimaging applications and genetically encodable biosensors.
Direction
VAZQUEZ SENTIS, MARCO EUGENIO (Tutorships)
Bouzada Reboredo, David (Co-tutorships)
VAZQUEZ SENTIS, MARCO EUGENIO (Tutorships)
Bouzada Reboredo, David (Co-tutorships)
Court
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
GONZALEZ BELLO, CONCEPCION (Chairman)
SECO CASTRO, JOSÉ MANUEL (Secretary)
VAZQUEZ LOPEZ, MIGUEL (Member)
Conformational Study of Cycloalkanes
Authorship
M.S.B.
Double bachelor degree in Physics and Chemistry
M.S.B.
Double bachelor degree in Physics and Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
In this work, a conformational study of cycloalkanes with rings containing between six and ten carbon atoms has been carried out using a conformational search algorithm for cyclic systems developed by Professor Fernández-Ramos’s group, at both high and low computational levels. First, low-level calculations were performed using the Hartree-Fock method, and the minima on the potential energy surface (PES) were studied. To explore a broader conformational space and gain a more detailed perspective of the possible conformations and their interconversion, transition states (TS) were also studied, which could subsequently evolve into stable conformations (PES minima). Density Functional Theory (DFT) was used as the high-level method to optimize the structures obtained at the low level. The analysis of the structures was based on the comparison of Cremer-Pople (CP) coordinates, for which a Python script was developed, and visual comparison with conformers reported in scientific publications. The experimentally found conformers mostly correspond to those described in the literature, although in some cases new structures were also discovered.
In this work, a conformational study of cycloalkanes with rings containing between six and ten carbon atoms has been carried out using a conformational search algorithm for cyclic systems developed by Professor Fernández-Ramos’s group, at both high and low computational levels. First, low-level calculations were performed using the Hartree-Fock method, and the minima on the potential energy surface (PES) were studied. To explore a broader conformational space and gain a more detailed perspective of the possible conformations and their interconversion, transition states (TS) were also studied, which could subsequently evolve into stable conformations (PES minima). Density Functional Theory (DFT) was used as the high-level method to optimize the structures obtained at the low level. The analysis of the structures was based on the comparison of Cremer-Pople (CP) coordinates, for which a Python script was developed, and visual comparison with conformers reported in scientific publications. The experimentally found conformers mostly correspond to those described in the literature, although in some cases new structures were also discovered.
Direction
FERNANDEZ RAMOS, ANTONIO (Tutorships)
CASTIÑEIRA REIS, MARTA (Co-tutorships)
FERNANDEZ RAMOS, ANTONIO (Tutorships)
CASTIÑEIRA REIS, MARTA (Co-tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
Search for astrophysical sources of neutrinos and gamma rays through space-time autocorrelations of atmospheric cascades at the Pierre Auger Observatory
Authorship
M.S.B.
Double bachelor degree in Physics and Chemistry
M.S.B.
Double bachelor degree in Physics and Chemistry
Defense date
09.15.2025 11:00
09.15.2025 11:00
Summary
This work is a study of cosmic rays focused on the analysis of their arrival directions at Earth and the identification of their astrophysical sources using computational and statistical methods, based on public data from the Pierre Auger Observatory. The study addressed the case in which the distribution of arrival directions of cosmic rays at Earth is isotropic or not, thereby evaluating the hypothesis of isotropy against the existence of sources of transient events, specifically active galactic nuclei. The comparison methodology was based on analyzing the temporal differences of cosmic rays incident in the atmosphere and counting simultaneous events or doublets.
This work is a study of cosmic rays focused on the analysis of their arrival directions at Earth and the identification of their astrophysical sources using computational and statistical methods, based on public data from the Pierre Auger Observatory. The study addressed the case in which the distribution of arrival directions of cosmic rays at Earth is isotropic or not, thereby evaluating the hypothesis of isotropy against the existence of sources of transient events, specifically active galactic nuclei. The comparison methodology was based on analyzing the temporal differences of cosmic rays incident in the atmosphere and counting simultaneous events or doublets.
Direction
CAZON BOADO, LORENZO (Tutorships)
JESUS DA SILVA MARTINS, MIGUEL ALEXANDRE (Co-tutorships)
CAZON BOADO, LORENZO (Tutorships)
JESUS DA SILVA MARTINS, MIGUEL ALEXANDRE (Co-tutorships)
Court
GONZALEZ FERREIRO, ELENA (Chairman)
VAZQUEZ RAMALLO, MANUEL (Secretary)
BAO VARELA, Mª CARMEN (Member)
GONZALEZ FERREIRO, ELENA (Chairman)
VAZQUEZ RAMALLO, MANUEL (Secretary)
BAO VARELA, Mª CARMEN (Member)
Undergraduate dissertation
Authorship
M.J.S.P.
Double bachelor degree in Physics and Chemistry
M.J.S.P.
Double bachelor degree in Physics and Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Eutrophication is an environmental issue caused by the accumulation of nutrients, primarily phosphate and nitrate. The main consequences include the proliferation of microorganisms and aquatic plants, which lead to anoxic conditions and hinder photosynthesis. This results in a decline in water quality and damage to aquatic ecosystems. To address the problems caused by eutrophication in aquatic environments, nutrient reduction was investigated using iron hydroxides and Technosols. The effectiveness of these adsorbent materials for phosphate retention was evaluated as a function of pH in the presence of simple organic acids, used as precursors of natural organic matter. Additionally, the “ferrous wheel” hypothesis was applied to nitrate removal through its reduction in the presence of ferrihydrite or Technosol and simple organic acids. The results confirm that this approach is a viable alternative to mitigate the problem. Regarding phosphate, ferrihydrite demonstrated significant adsorption capacity, which decreased with increasing pH and in the presence of organic acids due to anion competition. In the case of nitrate, its removal was found to depend on both the pH and the nature of the organic acid, owing to their influence on the redox processes involved in anion reduction.
Eutrophication is an environmental issue caused by the accumulation of nutrients, primarily phosphate and nitrate. The main consequences include the proliferation of microorganisms and aquatic plants, which lead to anoxic conditions and hinder photosynthesis. This results in a decline in water quality and damage to aquatic ecosystems. To address the problems caused by eutrophication in aquatic environments, nutrient reduction was investigated using iron hydroxides and Technosols. The effectiveness of these adsorbent materials for phosphate retention was evaluated as a function of pH in the presence of simple organic acids, used as precursors of natural organic matter. Additionally, the “ferrous wheel” hypothesis was applied to nitrate removal through its reduction in the presence of ferrihydrite or Technosol and simple organic acids. The results confirm that this approach is a viable alternative to mitigate the problem. Regarding phosphate, ferrihydrite demonstrated significant adsorption capacity, which decreased with increasing pH and in the presence of organic acids due to anion competition. In the case of nitrate, its removal was found to depend on both the pH and the nature of the organic acid, owing to their influence on the redox processes involved in anion reduction.
Direction
Fiol López, Sarah (Tutorships)
Antelo Martínez, Juan (Co-tutorships)
Fiol López, Sarah (Tutorships)
Antelo Martínez, Juan (Co-tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
Study of sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in sludge samples
Authorship
S.S.A.
Bachelor of Chemistry
S.S.A.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds composed of multiple fused benzene rings, known for their persistence in the environment and their potential toxicity to living organisms. The main objective of this work is to propose the most suitable sample preparation methodology for the determination of PAHs in sludge, considering efficiency, precision, ease of implementation and the requirements of current legislation, through a review of the scientific literature. To achieve this, the general characteristics and specific features of the most commonly used sample preparation methods for extracting PAHs from matrices such as soils, sediments and sewage sludge are presented. Both traditional techniques such as Soxhlet extraction and less conventional methods like ultrasound assisted-extraction (USE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), and QuEChERS extraction are included. Advancements in separation and determination techniques are discussed, including gas chromatography coupled with mass spectrometry (GC-MS) and high-permformance liquid chromatography coupled with mass spectrometry (HPLC-MS). Recent scientific studies applying these methodologies are presented, highlighting specific analytical parameters and conditions. After establishing several criteria for the selection of the most appropriate methodology, the QuEChERS extraction method and GC-MS or HPLC-MS are finally proposed as a method for the separation and identification of PAHs.
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds composed of multiple fused benzene rings, known for their persistence in the environment and their potential toxicity to living organisms. The main objective of this work is to propose the most suitable sample preparation methodology for the determination of PAHs in sludge, considering efficiency, precision, ease of implementation and the requirements of current legislation, through a review of the scientific literature. To achieve this, the general characteristics and specific features of the most commonly used sample preparation methods for extracting PAHs from matrices such as soils, sediments and sewage sludge are presented. Both traditional techniques such as Soxhlet extraction and less conventional methods like ultrasound assisted-extraction (USE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), and QuEChERS extraction are included. Advancements in separation and determination techniques are discussed, including gas chromatography coupled with mass spectrometry (GC-MS) and high-permformance liquid chromatography coupled with mass spectrometry (HPLC-MS). Recent scientific studies applying these methodologies are presented, highlighting specific analytical parameters and conditions. After establishing several criteria for the selection of the most appropriate methodology, the QuEChERS extraction method and GC-MS or HPLC-MS are finally proposed as a method for the separation and identification of PAHs.
Direction
CASAIS LAIÑO, Mª DEL CARMEN (Tutorships)
CASAIS LAIÑO, Mª DEL CARMEN (Tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
Comparison of different methods for assessing the oral bioaccessibility of trace elements in foods
Authorship
I.T.C.
Bachelor of Chemistry
I.T.C.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
In the present final degree project, the bioaccessibility of various trace elements is evaluated in two food matrices. Two different in vitro digestion methods are used for this purpose, with the aim of analyzing whether the choice of method influences the results obtained. One method used by the GETEE group at USC since 2001 is selected, and another called INFOGEST 2.0, proposed by the INFOGEST international scientific consortium (international network on food digestion in the gastrointestinal tract). The total concentrations and those of the bioaccessible fraction are determined using inductively coupled plasma mass spectrometry (ICP-MS) and flame atomic absorption spectrophotometry (FAAS). With these results, the bioaccessibility of the trace elements in the samples subjected to the two in vitro digestion procedures evaluated is calculated. After data processing, a paired-sample hypothesis test was performed for each food matrix, where no statistically significant differences were found between the bioaccessibility percentages calculated by both methods.
In the present final degree project, the bioaccessibility of various trace elements is evaluated in two food matrices. Two different in vitro digestion methods are used for this purpose, with the aim of analyzing whether the choice of method influences the results obtained. One method used by the GETEE group at USC since 2001 is selected, and another called INFOGEST 2.0, proposed by the INFOGEST international scientific consortium (international network on food digestion in the gastrointestinal tract). The total concentrations and those of the bioaccessible fraction are determined using inductively coupled plasma mass spectrometry (ICP-MS) and flame atomic absorption spectrophotometry (FAAS). With these results, the bioaccessibility of the trace elements in the samples subjected to the two in vitro digestion procedures evaluated is calculated. After data processing, a paired-sample hypothesis test was performed for each food matrix, where no statistically significant differences were found between the bioaccessibility percentages calculated by both methods.
Direction
Domínguez González, María Raquel (Tutorships)
ABOAL SOMOZA, MANUEL (Co-tutorships)
Domínguez González, María Raquel (Tutorships)
ABOAL SOMOZA, MANUEL (Co-tutorships)
Court
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
FERNANDEZ RAMOS, ANTONIO (Chairman)
CASAIS LAIÑO, Mª DEL CARMEN (Secretary)
RODIL RODRIGUEZ, MARIA DEL ROSARIO (Member)
Determination of radon precursors in Galician rocks using electron spin resonance
Authorship
A.V.S.
Bachelor of Chemistry
A.V.S.
Bachelor of Chemistry
Defense date
09.18.2025 09:00
09.18.2025 09:00
Summary
Electron Spin Resonance (ESR) spectroscopy is a well-established technique for detecting radiation-induced paramagnetic defects in crystalline structures. In this work, its application to natural quartz samples from Galicia is explored, with the aim of evaluating its validity as a passive tool to estimate the accumulated dose of ionizing radiation, particularly that associated with the presence of gas Rn. Galicia is one of the regions with the highest natural concentration of Rn in Spain, due to its geology dominated by granitic rocks rich in U and Th. The study proposes the use of the paramagnetic centers E’ and [AlO4]0 in quartz as dosimetric indicators of accumulated radiation. The samples were subjected to the following procedure: quartz separation and purification, characterization by SEM-EDX, and ESR analysis under optimized conditions. Controlled gamma irradiations were carried out to obtain dose-response curves, as well as thermal treatments (annealing) to evaluate the stability of the signals. The results show high thermal stability of the E’ centers and allow the use of the concentration of oxygen vacancies as an approximation of the relative age of the studied rocks. Likewise, a correlation is observed between the intensity of the [AlO4]0 center signal and the geological context, which reinforces its potential usefulness as a descriptor of the radioactive activity of the terrain.
Electron Spin Resonance (ESR) spectroscopy is a well-established technique for detecting radiation-induced paramagnetic defects in crystalline structures. In this work, its application to natural quartz samples from Galicia is explored, with the aim of evaluating its validity as a passive tool to estimate the accumulated dose of ionizing radiation, particularly that associated with the presence of gas Rn. Galicia is one of the regions with the highest natural concentration of Rn in Spain, due to its geology dominated by granitic rocks rich in U and Th. The study proposes the use of the paramagnetic centers E’ and [AlO4]0 in quartz as dosimetric indicators of accumulated radiation. The samples were subjected to the following procedure: quartz separation and purification, characterization by SEM-EDX, and ESR analysis under optimized conditions. Controlled gamma irradiations were carried out to obtain dose-response curves, as well as thermal treatments (annealing) to evaluate the stability of the signals. The results show high thermal stability of the E’ centers and allow the use of the concentration of oxygen vacancies as an approximation of the relative age of the studied rocks. Likewise, a correlation is observed between the intensity of the [AlO4]0 center signal and the geological context, which reinforces its potential usefulness as a descriptor of the radioactive activity of the terrain.
Direction
RIVADULLA FERNANDEZ, JOSE FRANCISCO (Tutorships)
LAZZARI , MASSIMO (Co-tutorships)
RIVADULLA FERNANDEZ, JOSE FRANCISCO (Tutorships)
LAZZARI , MASSIMO (Co-tutorships)
Court
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)
FERNANDEZ RODRIGUEZ, BERTA (Chairman)
ESTEVEZ VALCARCEL, CARLOS MANUEL (Secretary)
YEBRA BIURRUN, MARIA DEL CARMEN (Member)