Search results for " Analytical"

Determinación de anfetamina, metanfetamina y efedrina con el reactivo espectrofotométrico 1,2-naftoquinona 4-sulfonato en muestras de orina y fármaco…

1994

Generalización del método de adición estándar del punto H (HPSAM) : eliminación de interferencias espectrales conocidas o desconocidas y optimización…

1995

Contribución al conocimiento y al desarrollo de aplicaciones analíticas de los efectos asociados a la espectrometría de lente térmica

1996

Ultrasound-Assisted Extraction, Centrifugation and Ultrafiltration: Multistage Process for Polyphenol Recovery from Purple Sweet Potatoes

2016

This work provides an evaluation of an ultrasound-assisted, combined extraction, centrifugation and ultrafiltration process for the optimal recovery of polyphenols. A purple sweet potato (PSP) extract has been obtained using ultrasonic circulating extraction equipment at a power of 840 W, a frequency of 59 kHz and using water as solvent. Extract ultrafiltration, using polyethersulfone (PES), was carried out for the recovery of polyphenol, protein and anthocyanin. Pre-treatment, via the centrifugation of purple sweet potato extract at 2500 rpm over 6 min, led to better polyphenol recovery, with satisfactory protein removal (reused for future purposes), than PSP extract filtration without cen…

Influence of photo-initiators in the preparation of methacrylate monoliths into poly(ethylene-co-tetrafluoroethylene) tubing for microbore HPLC.

2020

[EN] In this study, poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) polymeric monoliths were in situ developed within 0.75 mm i.d. poly(ethylene-co-tetrafluoroethylene) (ETFE) tubing by UV polymerization via three different free-radical initiators fscce-azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA) and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMPP). The influence of the nature of each photo-initiator and irradiation time on the morphological features of the polymer was investigated by scanning electron microscopy, and the chromatographic properties of the resulting microbore columns were evaluated using alkyl benzenes as test substances. The …

Improving the Frying Performance and Oxidative Stability of Refined Soybean Oil by Tocotrienol-Rich Unsaponifiable Matters of Kolkhoung (Pistacia khi…

2018

Increasing consumer awareness for all natural products has quickly led to growing research on new resources of potent and profitable natural antioxidants. In this context, for the first time, the Kolkhoung hull oil (KHO) (Pistacia khinjuk)-unsaponifiable matters (USM) (UHO) (100, 200, and 400 mg kg−1) were incorporated into refined soybean oil (RSO) and the oxidative stability of prepared oils was measured during 32 hours of frying. Then, the obtained results (oxidative stability) were compared to the samples containing tert-butyl hydroquinone (TBHQ) (100 mg kg−1) as a common synthetic antioxidant. According to the results of oxidative stability assays of acid values, conjugated diene value…

Retrospective analysis of pesticide metabolites in urine using liquid chromatography coupled to high-resolution mass spectrometry

2016

Abstract A comprehensive retrospective analysis of pesticide metabolites in urine was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS) that includes both post-run target (suspect screening) and non-target screening. An accurate-mass database comprising 263 pesticide metabolites was built and used for the post-run screening analysis. For non-target analysis, a “fragmentation-degradation” relationship strategy was selected. The proposed methodology was applied to 49 real urine samples from pregnant women. In the post-target analysis 26 pesticide metabolites were tentatively identified, 8 of which (2-diethylamino-6-methyl-pyrimidinol; 3-…

A new tool for evaluating and/or selecting analytical methods: Summarizing the information in a hexagon

2019

Abstract A quantitative evaluation tool is proposed, which aims to assess optimal selection or/and testing of analytical methods. Objective criteria related to analytical performance, sustainability, environmental impact and economic cost are evaluated through the definition of penalty points divided into five different blocks, namely, figures of merit, toxicity and safety, residues, carbon footprint and economic cost. For each block, the overall qualification is scaled from 0 to 4 and it is depicted on a regular hexagonal pictogram that allows a user friendly comparison of analytical procedures. The present evaluation tool aims to be a guideline for evaluating and/or selecting analytical p…

Research Directions of OLAP Personalizaton

2011

In this paper we have highlighted five existing approaches for introducing personalization in OLAP: preference constructors, dynamic personalization, visual OLAP, recommendations with user session analysis and recommendations with user profile analysis and have analyzed research papers within these directions. We have provided an evaluation in order to point out (i) personalization options, described in these approaches, and its applicability to OLAP schema elements, aggregate functions, OLAP operations, (ii) the type of constraints (hard, soft or other), used in each approach, (iii) the methods for obtaining user preferences and collecting user information. The goal of our paper is to syst…

OLAP Personalization with User-Describing Profiles

2010

In this paper we have highlighted five existing approaches for introducing personalization in OLAP: preference constructors, dynamic personalization, visual OLAP, recommendations with user session analysis and recommendations with user profile analysis and have analyzed research papers within these directions. We have pointed out applicability of personalization to OLAP schema elements in these approaches. The comparative analysis has been made in order to highlight a certain personalization approach. A new method has been proposed, which provides exhaustive description of interaction between user and data warehouse, using the concept of Zachman Framework [1, 2], according to which a set of…