Search results for " Analytical"
showing 10 items of 1453 documents
Dalla svolta linguistica alla svolta interpretativa: ermeneutica giuridica e filosofia giusanalitica a confronto
2020
The interpretative turn that characterized the legal philosophical debate in the last decades offers a privileged viewpoint to observe the dispute between legal analytical philosophy and legal hermeneutics. On one hand it is certainly true that the two traditions of thought have actually been converging for many years; on the other, it is worth noting that legal analytical philosophers are struggling to accept the interpretative turn and, as a consequence, to abandon the neutrality thesis peculiar of methodological legal positivism. Looking at the hermeneutics instead, its next step should be that of rejecting the one right answer thesis, with the awareness that it does not necessarily lead…
Study of the column efficiency using gradient elution based on Van Deemter plots.
2018
Performance of chromatographic columns is of major importance in the development of more efficient separation methods. So far, a common practice is to study the column behavior in isocratic elution by modifying the flow rate and fitting the theoretical plate height values versus the mobile phase linear velocity, according to the Van Deemter equation. In this work, an approach is presented to extend the measurement of efficiency to linear gradient elution, where the mean retention factor is kept constant at each assayed flow. This avoids a possible source of uncertainty due to the change in the distribution equilibria profile, and makes the mean interactions with the stationary phase in grad…
Determination of pesticides and veterinary drug residues in food by liquid chromatography-mass spectrometry: A review
2015
Monitoring of pesticides and veterinary drug residues is required to enforce legislation and guarantee food safety. Liquid chromatography-mass spectrometry (LC-MS) is the prevailing technique for assessing both types of residues because LC offers a versatile and universal separation mechanism suitable for non-gas chromatography (GC) amenable and the majority of GC-amenable compounds. This characteristic becomes more relevant when LC is coupled to MS because the high sensitivity and specificity of the detector allows to apply generic sample preparation procedures, which simultaneously extract a wide variety of residues with different physico-chemical properties. Determination of metabolites …
Analytical chemistry on many-center chiral compounds based on vibrational circular dichroism: Absolute configuration assignments and determination of…
2019
The absolute configuration of a chiral molecule is key to its biological activity. Being able to find out what this configuration is, is thus crucial for a wide range of applications. The difficulties associated with such a determination steeply rise as the number of chiral centers in a given compound becomes larger. Concurrently, it becomes increasingly more challenging to determine the levels and identity of potential stereochemical contaminants in a given sample with one and the same technique, leading in practice to extensive and laborious efforts employing multiple analytical techniques. Here, experimental and theoretical studies based on Vibrational Circular Dichroism (VCD) are presen…
Distribution of YLOID in soil-grapevine system (Vitis vinifera L.) as tool for geographical characterization of agro-food products. A two years case …
2017
The knowledge of a chemistry relationship between the soil and the agricultural products is an important tool for the quality assessment of food. We studied YLOID (Y, La and lanthanoids), recognized as very useful tracers due their coherent and predictable behavior, to trace and evaluate their distribution from soil to the grape in Vitis vinifera L. Because much of the world’s viticulture is based on grafting, and rootstocks have proved affect vine growth, yield, fruit and wine quality, we carried out experimental trials to analyse the YLOID distribution of two different red cultivars, grafted onto six different rootstocks, on the same soil. The YLOID amounts, the relationship Heavy vs Ligh…
One-sensor electronic olfactometer for rapid sorting of fresh fruit juices
2001
Abstract A low-cost electronic olfactometer was developed, based on virtual sensors array (an array of signals from a single metal oxide sensor) and on our proprietary semi-automated sampling system. This concept enables us to drastically improve the sensitivity and selectivity of the entire olfactometer to make it suited to food products analysis. Each step of the prototype was checked separately in earlier work, and finally the system performance was evaluated first on pure chemicals, and then at-line for grape juice during grape-harvesting in Champagne. It is shown that over a 3-week vintage period, the drift of the unique-sensor was quite low (absolute baseline value: avg., 2152; std., …
Reproducciones museísticas de piezas arqueológicas metálicas: de las técnicas de fundición a la utilización de metales artificiales
2017
Las reproducciones de piezas arqueológicas cumplen una necesaria función en nuestras sociedades en tanto permiten una multiplicidad inducida del original, que redunda en beneficios para la conservación, divulgación y promoción de nuestro patrimonio. La reproducción de objetos metálicos ha supuesto un desafío para las instituciones museísticas, dada la complejidad de emular metales, y así se ha propuesto en muchos casos la implementación de técnicas tradicionales como la fundición a la cera perdida o los procesos electrolíticos, limitando la investigación en otros materiales El presente artículo propone una solución alternativa, fundamentada en el uso de composites de resinas termoestables c…
Evaluating the Effect of Stimuli Color and Frequency on SSVEP
2020
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Ultrasound as a Promising Tool for the Green Extraction of Specialized Metabolites from Some Culinary Spices
2021
Spices are a popular food of plant origin, rich in various phytochemicals and recognized for their numerous properties. The aim of the study was to evaluate the antioxidant and antimicrobial activity, as well as the content of specialized metabolites, of aqueous extracts of three spice species––garlic (Allium sativum L.), ginger (Zingiber officinalle L.) and turmeric (Curcuma longa L.)––prepared by green extraction methods. Ultrasound treatment increased the chromaticity parameter b value of turmeric and ginger extracts, thus indicating a higher yellow color predominantly due to curcuminoids characteristic of these species. Ultrasound-assisted extraction significantly increased the content …
$$PO^2$$ - A Process and Observation Ontology in Food Science. Application to Dairy Gels
2016
This paper focuses on the knowledge representation task for an interdisciplinary project called Delicious concerning the production and transformation processes in food science. The originality of this project is to combine data from different disciplines like food composition, food structure, sensorial perception and nutrition. Available data sets are described using different vocabularies and are stored in different formats. Therefore there is a need to define an ontology, called \(PO^2\) (Process and Observation Ontology), as a common and standardized vocabulary for this project. The scenario 6 of the NeON methodology was used for building \(PO^2\) and the core component is implemented i…