Formulation of the System of Isohydric Solutions

The isohydricity (pH constancy) as the property referred to mixtures of acids or bases, is illustrated on a simple example of the solutions: HL (C0, mol/L) and HL (C mol/L) mixed according to titrimetric mode (pH titration). A new derivation of the Michałowski formula 120 10 pKC C C expressing this property is presented, and its applicability for determi-nation of pK1 = – logK1 value is indicated. The principle of the isohydric method of pK1 determination is also outlined

Antioxidant Capacity of Anthocyanins and other Vegetal Pigments

Anthocyanins are the largest group of phenolic pigments, being effective hydrogen donors [...

Youden Two-Sample Method

The results obtained when testing materials, equipment and procedures are not generally identical. Factors that influence the magnitude of the results are not fully controllable. As such, the interpretation and analysis of results must take into account the variations caused by numerous and random unavoidable causes. Intercomparison exercises are considered of being of importance, as they do allow the examination of the analytical process and their generated results. Youden plot is particularly aimed at interlaboratory comparisons. The raw results provided by the participating laboratories are treated by a statistical method applied by the centre performing the trial. In order to materialize this, two similar materials with small differences in the concentration of the characteristics are required. The advantage of Youden analysis is its ability to separate the random errors with a minimum effort by participants in the design from the point of view of the analytical requirement. This book chapter illustrates the method that has been applied to elaborate on data covering a diverse scientific field: polyunsaturated fatty acids in fat and oils, total blood cholesterol and aspirin in pharmaceutical preparations. Finally, liquid chromatography with tandem mass spectrometry detector has been applied to the determination of an emerging contaminant, methylparaben (MeP), in surface waters

Facultad de Farmacia de la Universidad de Sevilla: implantación del espíritu ECTS propio del EEES

The implementation process of the ECTS concepts in the Faculty of Pharmacy at the University of Seville is being studied. The main objectives of this Pilot Scheme can be summarized in two fundamental aspects: (i) training of the professors in the new education methodologies according to the EHEA concepts and (ii) obtaining of experimental results that make us possible to justify the adequate personal and infrastructures requirements. The obtained results are very promising; nevertheless, several actions have been detected in order to yield with the EHEA possibilities. These actions are related (i) to adequate the students / professors ratio, (ii) to establish coordination groups and (iii) to develop a tutorial action so as to improve the students implication.En este trabajo se aborda el estudio del proceso de implantación del Sistema de Transferencia de Créditos Europeos (ECTS), unidad fundamental del Espacio Europeo de Educación Superior (EEES), en la Titulación actual de Farmacia de la Universidad de Sevilla. Tras unas consideraciones previas, se establecen los objetivos fundamentales del Programa Piloto de implantación ECTS, que se resumen en dos aspectos básicos: (i) entrenamiento del profesorado de la Facultad en el nuevo modelo educativo propuesto por la Declaración de Bolonia y (ii) obtención de resultados experimentales que posibiliten justificar necesidades y exigencias, tanto personales como materiales, ante la próxima implantación de los nuevos planes de estudio según el crédito europeo. Los resultados son muy positivos, pero si se pretende aprovechar correctamente las posibilidades ofertadas por este nuevo sistema, señalan claramente (i) la necesidad de adaptar el número de estudiantes por grupo, tanto dotando del personal necesario para la docencia como adecuando las infraestructuras, (ii) la conveniencia de crear equipos de coordinación por curso y por titulación y (iii) crear acciones que promuevan el desarrollo de un sistema tutorial de orientación

A Potentiometric Evaluation of Stability Constants of Two-Step Overlapping Equilibria via a Bilogarithmic Hyperbolic Cosine Method

A bilogarithmic hyperbolic cosine method for the evaluation of overlapping formation constants at varying (or fixed) ionic strength is devised in this paper and applied to data reported in the analytical literature, i.e. succinic acid system, Cu(II)-glycine system and Ag(I)-aminobutan -1-ol system. The method is based on the linearization of the formation function ñ = f(pH) or ñ = f(pL) data. A theoretical slope of unity should be obtained thus proving the correctness of the assumed equilibria. An additional advantage of the bilogarithmic method proposed is that it provides a closed scale representation of Y and X unlike other plots. This paper forms part of an investigation into the uses of bilo garithmic methods and hyperbolic functions in parameter estimation. Methods based on the application of spectrophotometric measurements have been the subject of recent studies

The Kjeldahl Titrimetric Finish: On the Ammonia Titration Trapping in Boric Acid

Kjeldahl method using concentrated boric acid is a common practice in many laboratories. A thorough study of the titration with hydrochloric acid of ammonia trapped in a solution of boric acid is made in an attempt to explain the fundamentals of a widely applied standard method. A new potentiometric method for the determination of the end point in the Kjeldahl titrimetric finish is proposed based on the linearization of the titration curve of the ammonia‐boric acid system. The method is strictly based on mole and charge balances, and no approximations are made in deriving the equations. The proposed method has proved very accurate when applied to synthetic titration curves and data. Some problems, however, are experienced in the practice, because the behavior of the experimental system studied is far from the expected one on the basis of the theoretical model. However, a slight modification of the devised method has been applied to the experimental titration of ammonia with hydrochloric acid, in boric acid as trapping solution, getting good results

State of the Art of Anthocyanins: Antioxidant Activity, Sources, Bioavailability, and Therapeutic Effect in Human Health

The antioxidant activity of anthocyanins in food is well known. Numerous antioxidant assays have been proposed to measure the capacity of anthocyanins to prevent the oxidation process that naturally occurs. Different solvents, temperatures, and pH levels are applied in each assay, and these factors should be taken into account in order to obtain useful and reproducible results. The concentration and the structure of these compounds are directly related to their antioxidant capacity and their environment. However, the effectiveness of the anthocyanin ingestion against diseases is also influenced by its bioavailability. Novel methodologies that simulate the digestion process have been developed in order to facilitate the current knowledge of anthocyanins bioavailability. Studies highlight the potential synergy effect between parent compounds and their derivatives (metabolites, conjugated products, and microbe-generated metabolites). The aim of this review is to provide an overview of advantages and disadvantages of the most common methods to determine the antioxidant activity of anthocyanins, chemical structure, and concentration of these compounds in different edible fruits, vegetables, and plants; their bioavailability after intake; as well as the main therapeutic effect described in the scientific literature

Intersecting Straight Lines: Titrimetric Applications

Plotting two straight line graphs from the experimental data and determining the point of their intersection solve a number of problems in analytical chemistry (i.e., potentiometric and conductometric titrations, the composition of metal-chelate complexes and binding interactions as ligand-protein). The relation between conductometric titration and the volume of titrant added lead to segmented linear titration curves, the endpoint being defined by the intersection of the two straight line segments. The estimation of the statistical uncertainty of the end point of intersecting straight lines is a topic scarcely treated in detail in a textbook or specialized analytical monographs. For this reason, a detailed treatment with that purpose in mind is addressed in this chapter. The theoretical basis of a variety of methods such as first-order propagation of variance (random error propagation law), Fieller’s theorem and two approaches based on intersecting confidence bands are explained in detail. Several experimental systems described in the literature are the subject of study, with the aim of gaining knowledge and experience in the application of the possible methods of uncertainty estimation. Finally, the developed theory has been applied to the conductivity measurements in triplicate in the titration of a mixture of hydrochloric acid and acetic acid with potassium hydroxide

Ayer, hoy y mañana de los huertos urbanos en Andalucía

Es un resumen de la conferencia impartida en la Facultad de Ciencias de la Universidad de Málaga, el 7 de Abril de 2014, por D. Raúl Puente Asuero. Invitado por el profesor Miguel Ángel Quesada Felice (Dpto de Biología Vegetal)Hasta el año 2007 son escasos los huertos urbanos que se han creado en Andalucía. Sin embargo, la crisis en España (2008 - …), que comenzó siendo una crisis económica e inmobiliaria, está teniendo como consecuencias una crisis social sin precedentes (desempleo, desahucios, emigración) y una crisis territorial y medioambiental (litoral urbanizado, regresión de playas, desaparición de humedales, etc) de la que aún no se vislumbra su fin. En este contexto de multicrisis y como mecanismo de respuesta de la población, se está produciendo un crecimiento exponencial de los huertos urbanos en Andalucía con una clara vocación asistencial, de autoconsumo, de garante de la soberanía y la seguridad alimentaria y como recurso social para familias desfavorecidas. Los huertos urbanos, además de proporcionar alimentos de calidad, son espacios que fortalecen el tejido social de las ciudades y pueblos actuando como mecanismo de resistencia y supervivencia frente a situaciones extremas como pueden ser las crisis económicas, los conflictos armados, las crisis alimentarias, etc. El objetivo de la charla será desvelar el proceso mediante el cual aparecen nuevos huertos urbanos a partir de 2008 con orígenes, finalidades y características muy singulares así como sus efectos sociales, económicos y ambientales en Andalucía.Campus de Excelencia Internacional, Andalucía Tech. Universidad de Málag