Dpto. Química Física y Química Inorgánica - Capítulos de monografías https://uvadoc.uva.es/handle/10324/1405 2026-04-15T01:10:13Z 2026-04-15T01:10:13Z Mu, Manting Peñas de Frutos, Marconi Nicolás García Melchor, Max https://uvadoc.uva.es/handle/10324/67704 2024-05-17T19:02:54Z 2024-01-01T00:00:00Z

Bimetal lic reagents fea tur ing one main-group el e ment and a first-row tran si tion metal cen tre have been the fo cus of ex ten sive re search due to their nu mer ous ap pli ca tions. In par tic u lar, the re gios e lec tive ac ti va tion of C–H bonds us ing bimetal lic com plexes has at tracted sig nif i cant at ten tion be cause of the ubiq ui tous pres ence of these bonds in or ganic com pounds, as well as the mild re ac tion con di tions and good atom econ - omy that these com plexes of fer. How ever, their re ac tiv ity is of ten not well un der - stood, which has prompted den sity func tional the ory (DFT) stud ies to shed light into the un der ly ing mech a nisms. In this chap ter, we re view some of the chal lenges as so ci - ated with the com pu ta tional mod el ling of bimetal lic C–H met al la tion processes (and re lated re ac tions) which may com pro mise the con clu sions drawn from these stud ies. Some il lus tra tive ex am ples are pro vided to high light, for in stance, the of ten-ne - glected ef fects that silent donors and non-in no cent sol vents can have on chem i cal spe ci a tion and lig and scram bling with bimetal lic sys tems, which in ti mately de ter - mine their chem i cal re ac tiv ity. In ad di tion, we dis cuss the im por tance of choos ing an ap pro pri ate the o ret i cal model when deal ing with ion-pair species and out line some com pu ta tional tools to get fur ther in sights into rel e vant in ter ac tions in flu enc ing sta - bil ity, while also ex am in ing their po ten tial uses and mis uses. Fi nally, we dis cuss an ap proach that com bines hy brid sol va tion mod els and mi cro ki netic mod el ling to cor - rectly de scribe the in flu ence of co or di nat ing sol vents on chem i cal re ac tiv ity.

2024-01-01T00:00:00Z Rodríguez Méndez, María Luz Saja Saez, José Antonio De Medina Plaza, Cristina García Hernández, Celia https://uvadoc.uva.es/handle/10324/21584 2025-02-18T09:04:14Z 2016-01-01T00:00:00Z

Electronic noses and tongues are the products of advanced chemical and physical sciences combined with intuitive integration of sensors, microprocessors, advanced informatics and statistics. They include for example resistive, optical, electrochemical or piezoelectric platforms where a variety of sensing materials (including among many others, metal oxide semiconductors, conducting polymers, nanoparticles, phthalocyanines or enzymes) have been immobilized using a variety of techniques. Some of these devices are available commercially, whereas others are home-grown devices that require commercialisation. Electronic noses and tongues have been used to characterize components that contribute to sensory or compositional profiles, from ripening to harvesting and from storage of raw materials to packaging and consumption. Electronic noses and tongues are thus suitable for high-throughput analysis, quality control or to determine the nature and extent of spoilage and adulteration. These devices have also been used to ascertain the geographical origins of food and mixtures. Devices used to analyse one particular food item can theoretically be adapted for other food items or components. This does not just mean the re-deploying the sensing devices but also the mode of statistical analysis. This includes supervised and no supervised tools such as principal component analysis (PCA), linear discriminant analysis (LDA), partial least squares (PLS), artificial neural networks (ANN), etc. In other words, there is cross transference of chemistry, physics, concepts, techniques, findings and approaches from one food to another. However, finding all this information in a coherent and comprehensive text has been problematical as hitherto no publication has attempted to marshal together all the relevant information on these important devices in relation to food science. This is addressed in “Electronic Noses and Tongues in Food Science”. Its unique feature is the three parts dedicated to the electronic nose, the electronic tongue and combined systems of electronic nose and tongue. Part I covers a description of electronic nose systems and their applications to the analysis of the volatile composition of different foods and beverages. Part II focuses on the electronic tongue, which has become increasingly important over recent years because it can analyse complex liquids such as wines or milks by direct immersion in the samples and not restricted to the headspace. Part III covers newer developments combining electronic nose and electronic tongue. Each part presents the main applications in the food industry. Classical applications in the field of meat, wines, dairy products or beers have been presented but also other less known applications such as the detection of gliadins or the assessment of the phenolic content in foods. The book is designed for food scientists, technologist, food-industry workers, as well as research scientists. Contributions are from leading national and international experts, including those from world renowned institutions. Readers can dip into the book for reference purposes, read any chapter as a standalone treatise, read it from cover to cover if food analysis is an integral part of their day-to-day job. I must finish by thanking all of the contributors to the book, each a recognised expert in their field. I also thank Elsevier Publishing for all the guidance on pulling together such an eclectic book. Finally, many thanks to my colleagues and PhD students for their help and support!

2016-01-01T00:00:00Z Rodríguez Méndez, María Luz García Hernández, Celia Medina Plaza, Cristina García Cabezón, Ana Cristina Paniagua Albillos, David Rodríguez Sánchez, Silvia Saja Saez, José Antonio De https://uvadoc.uva.es/handle/10324/21579 2025-02-18T09:03:02Z 2016-01-01T00:00:00Z

The Mediterranean diet has largely demonstrated its health benefits which are related to the intake of antioxidants. Besides the health benefits, antioxidants influence in the organoleptic characteristics, the quality and the preservation of foods and beverages. Although a variety of methods have been described to detect antioxidants and to evaluate the antioxidant capacity of foods, field experiments still represent a challenge. In this context, electrochemical techniques can represent an advantage thanks to higher sensitivity, short experimental times and inherent portability. In this chapter, the electrochemical sensors dedicated to the analysis of antioxidants will be presented. Particular attention will be paid to voltammetric sensors. The methods used to improve their selectivity and sensitivity by modifying the surface using chemical or biological materials will be described. The new developments obtained thanks to new nanomaterials and nanostructured films will be evidenced. Finally, the advantages of multisensor systems based on electrochemical sensors will be described.

2016-01-01T00:00:00Z