Ana Sayago

Comparison of Different Extraction Methods to Determine Phenolic Compounds in Virgin Olive Oil

A comparison between different extraction methods has been performed in order to assess their effectiveness for the analysis of total phenols (liquid–liquid extraction (LLE), liquid–liquid micro extraction (LLME), and ultrasound liquid–liquid extraction (USE)) and individual phenols (LLME, USE, and solid-phase extraction (SPE)) from virgin olive oil (VOO). Statistical analysis of the analytical data obtained for the total phenol content of a VOO, showed that LLME and USE can represent a reliable alternative to the traditional procedure based on LLE that needs more amount of sample, generates more wastes, and is more time consuming. When an olive oil spiked with phenols was used to test the efficiency of LLME, USE, and SPE methods, the statistical analysis of the data obtained for each individual phenol, again proved LLME and USE methods to be the most suitable, in terms of precision and recoveries, for this purpose. The analysis of real samples (Arbequina and Picual cultivars) confirmed the results obtained for the spiked oil.

Optimization of an HPLC-HG-AFS method for screening Sb(V), Sb(III), and Me3SbBr2 in water samples

A procedure for the separation and determination of inorganic and organic species of antimony based on the use of coupled high-performance liquid chromatography (HPLC) hydride generation (HG) atomic fluorescence spectrometry (AFS) is described. Me3SbBr2 and inorganic Sb(V) and Sb(III) were separated on an anion-exchange column [Hamilton PRPX-100 (100 × 4.1 mm)] using the concentration gradient between potassium hydroxide, 20 mM pH 11, and ammonium tartrate, 200 mM pH 5. The flow rate through the column was 1.5 mL min−1. The retention times were 0.98, 1.71 and 5.03 min for Me3SbBr2, Sb(V) and Sb(III), respectively. The hydrides were generated on-line with 3% m/v NaBH4 and 2 mol l−1 HNO3 solutions. The intensity of emission was linearly related to the concentration of the derivatized Me3SbBr2 species in the range 1.0–50.0 µg l−1 (r = 0.9996), Sb(V) species in the range 1.0–50.0 µg l−1 (r = 0.9998) and Sb(III) in the range 2.5–50.0 µg l−1 (r = 0.9998), with detection limits of 0.04 µg l−1 for Me3SbBr2, 0.09 µg l−1 for Sb(V) and 0.26 µg l−1 for Sb(III). The precisions evaluated using the relative standard deviation (RSD) were 6.8%, 2.4% and 3.3% for Me3SbBr2, Sb(V) and Sb(III), respectively. The method has a sensitivity suitable for monitoring drinking and surface waters according to the regulations established by the EU directives for antimony (10 ug 1−1), and it was applied to the speciation of inorganic and organic antimony in several spiked water samples. The precisions for well water, Merck and mineral water were limited in relation to Me3SbBr2 due to its conversion to Sb(V).

Metabolomics in Alzheimer’s disease: The need of complementary analytical platforms for the identification of biomarkers to unravel the underlying pathology

Alzheimers disease is a complex neurodegenerative disorder characterized by a multi-factorial etiology, not completely understood to date. In this context, the application of metabolomics is emerging in the last years because of its potential to monitor molecular alterations associated with disease pathogenesis and progression, as well as to discover candidate diagnostic biomarkers. However, the huge heterogeneity and dynamism of the human metabolome makes impossible the simultaneous determination of the entire set of metabolites from complex biological samples. Thus, the most common strategy to get a comprehensive overview of the organisms phenotypic expression is the combined use of complementary metabolomic platforms. In this review, we summarize the advantages and limitations of the most important analytical techniques usually employed in metabolomics, including nuclear magnetic resonance, direct infusion mass spectrometry and hyphenated approaches based on the coupling of orthogonal separation mechanisms (i.e. liquid chromatography, gas chromatography, capillary electrophoresis) with mass spectrometry. Moreover, the suitability of metabolomics to unravel the complex pathology underlying to Alzheimers disease is also presented.

Characterization of a bacterioruberin-producing Haloarchaea isolated from the marshlands of the Odiel river in the southwest of Spain.

In this work, we describe the isolation, identification, pigment characterization, and optimization of the culture conditions for a haloarchaea strain isolated from salt evaporation ponds in the Odiel river, at Southwest of Spain. The haloarchaea belongs to the genus Halorobrum, as deduced from the analysis of its 16S rRNA encoding gene and has been designated as Halorubrum sp. SH1. The growth conditions for the new strain were optimized studying temperature, NaCl concentration, agitation rate and light intensity. The C50‐carotenoids, bacterioruberin, and its derivatives bisanhydrobacterioruberin and trisanhydrobacterioruberin, were found to be the predominant pigments produced by this strain of Halorubrum, as determined using HPLC‐DAD and UHPLC‐ESI‐MS/MS techniques. This extremely halophilic archaeon could be a good candidate for the production of bacterioruberins of high added‐value due to their coloring, antioxidant, and possible anticancer properties.

Extraction and Determination of Phenolic Compounds in the Berries of Sorbus americana Marsh and Lonicera oblongifolia (Goldie) Hook

Phenolic compound content in Sorbus americana Marsh and Lonicera oblongifolia (Goldie) Hook berries was determined for the first time. An improved solid-liquid microextraction (SLME) method combining with high-performance liquid chromatography (HPLC)-diode array detector (DAD)-mass spectrometry (MS) has been developed to determine the phenolic compounds present in these berries, reducing the amount of sample, reagents, and time consumed. The major phenolic compound identified and quantified was 3-O-caffeoylquinic acid (3-CQA) in both berries. To a lesser extent, 5-O-caffeoylquinic acid (5-CQA) and quercetin-3-O-glucoside (QG) were also determined. The existence of these phenolic compounds and the great abundance of these fruits in the northeast of North America make S. americana Marsh and L. oblongifolia Hook berries a new and excellent source of natural phenolic compounds (antioxidants), which can be very useful in biotechnological exploitation.

An Overview on the Importance of Combining Complementary Analytical Platforms in Metabolomic Research

The analytical bias introduced by most of the commonly used techniques in metabolomics considerably hinders the simultaneous detection of all metabolites present in complex biological samples. In order to solve this limitation, the combination of complementary approaches is emerging in recent years as the most suitable strategy in order to maximize metabolite coverage. This review article presents a general overview of the most important analytical techniques usually employed in metabolomics: nuclear magnetic resonance, mass spectrometry and hybrid approaches. Furthermore, we emphasize the potential of integrating various tools in the form of metabolomic multi-platforms in order to get a deeper metabolome characterization, for which a revision of the existing literature in this field is provided. This review is not intended to be exhaustive but, rather, to give a practical and concise guide to readers not familiar with analytical chemistry on the considerations to account for the proper selection of the technique to be used in a metabolomic experiment in biomedical research.

Mass Spectrometry-Based Metabolomic Multiplatform for Alzheimer’s Disease Research

The integration of complementary analytical platforms has emerged as a suitable strategy to perform a comprehensive metabolomic characterization of complex biological systems. In this work, we describe the most important issues to be considered for the application of a mass spectrometry multiplatform in Alzheimers disease research, which combines direct analysis with electrospray and atmospheric pressure photoionization sources, as well as orthogonal hyphenated approaches based on reversed-phase ultrahigh-performance liquid chromatography and gas chromatography. These procedures have been optimized for the analysis of multiple biological samples from human patients and transgenic animal models, including blood serum, various brain regions (e.g., hippocampus, cortex, cerebellum, striatum, olfactory bulbs), and other peripheral organs (e.g., liver, kidney, spleen, thymus). It is noteworthy that the metabolomic pipeline here detailed has demonstrated a great potential for the investigation of metabolic perturbations underlying Alzheimers disease pathogenesis.

Combination of complementary data mining methods for geographical characterization of extra virgin olive oils based on mineral composition

This work explores the potential of multi-element fingerprinting in combination with advanced data mining strategies to assess the geographical origin of extra virgin olive oil samples. For this purpose, the concentrations of 55 elements were determined in 125 oil samples from multiple Spanish geographic areas. Several unsupervised and supervised multivariate statistical techniques were used to build classification models and investigate the relationship between mineral composition of olive oils and their provenance. Results showed that Spanish extra virgin olive oils exhibit characteristic element profiles, which can be differentiated on the basis of their origin in accordance with three geographical areas: Atlantic coast (Huelva province), Mediterranean coast and inland regions. Furthermore, statistical modelling yielded high sensitivity and specificity, principally when random forest and support vector machines were employed, thus demonstrating the utility of these techniques in food traceability and authenticity research.

Characterization and evaluation of phenolic profiles and color as potential discriminating features among Spanish extra virgin olive oils with protected designation of origin

Changes in phenolic profiles and color parameters can help to differentiate between extra virgin olive oils (EVOOs) with protected designation of origin (PDO). Phenolic profile characterization and CIELAB parameters determination of 9 PDO EVOOs from Spain were developed. Both properties of EVOOs are very relevant to their commercialization and increase the product value. The Serrana de Espadán olive cultivar was characterized for the first time and showed the highest pinoresinol concentrations and clarities in these olive oils, which are important values for the product image. To detect fraudulent instrumental work and implement quality control, principal component analysis (PCA) and linear discriminant analysis (LDA) were performed. EVOO geographical origin and cultivar distributions were achieved with cumulative variances of 93.4% and 92.4%, respectively. A categorization of PDO EVOOs was proposed using the following 7 phenolic compounds: phenolic alcohols (tyrosol and hydroxytyrosol), 3,4-DHPEA-EDA, 3,4-DHPEA-EA, p-HPEA-EDA, pinoresinol and total phenolic compounds.

Desarrollo de Procedimientos Normalizados de Trabajo: una forma Innovadora de realizar las Prácticas en Asignaturas de Ciencias Experimentales

The present work proposes the use of autonomous learning for students through the elaboration of standard operating procedures (SOPs). This experience is carried out within the course Analytical Methods for Quality Assurance of the majors Chemical Engineering and Technical Industrial Engineering in Chemistry at the University of Huelva in Spain. The preparation of the SOPs and the working instructions make that repetitive actions are performed in the same way regardless of the person who performs the tasks. Therefore, SOPs represent a good tool in the practical formation of students. The degree of satisfaction of the students in using this method of autonomous learning has been evaluated through individual interviews, group tutorial and opinion polls. The results have been satisfactory and the activity has resulted to be a motivating agent for the learning process.En este trabajo se plantea al alumno el aprendizaje autonomo mediante la elaboracion de procedimientos normalizados de trabajo (PNTs). La experiencia se realiza en la asignatura Metodos Analiticos de Control de Calidad del plan de Ingenieria Quimica y de Ingenieria Tecnica Industrial especialidad Quimica de la Universidad de Huelva en Espana. La elaboracion de los PNTs e instrucciones de trabajo facilitan que las tareas repetitivas se realicen siempre de la misma forma con independencia de la persona que las realiza, constituyendo una buena herramienta para la formacion practica del alumnado. El grado de satisfaccion del alumno para el aprendizaje autonomo ha sido evaluado a traves de entrevistas personales, tutorias grupales y encuestas. Los resultados han sido muy satisfactorios y la actividad ha resultado ser un importante agente motivador del aprendizajeThe present work proposes the use of autonomous learning for students through the elaboration of standard operating procedures (SOPs). This experience is carried out within the course Analytical Methods for Quality Assurance of the majors Chemical Engineering and Technical Industrial Engineering in Chemistry at the University of Huelva in Spain. The preparation of the SOPs and the working instructions make that repetitive actions are performed in the same way regardless of the person who performs the tasks. Therefore, SOPs represent a good tool in the practical formation of students. The degree of satisfaction of the students in using this method of autonomous learning has been evaluated through individual interviews, group tutorial and opinion polls. The results have been satisfactory and the activity has resulted to be a motivating agent for the learning process.