Search results for "Extraction"
showing 10 items of 2072 documents
Multiresidue analysis of organic pollutants by in-tube solid phase microextraction coupled to ultra-high performance liquid chromatography-electrospr…
2013
In this work, in-tube solid phase microextraction (IT-SPME) coupling with ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) multiresidue analytical method has been proposed for the first time for on-line enrichment of 9 analytes included in Water Frame Directive 2000/60/EC (WFD). The device was equipped with a GC TRB-5 capillary column, used as pre-concentration loop, and two conventional six-port injection valves. Water sample and desorption solvent volumes were tested. The optimum conditions were 4mL of processed sample followed by elution with 40μL of methanol. The analytes were detected with a mass spectrometer after being ionized positively using an elect…
Analysis of carbamate and phenylurea pesticide residues in fruit juices by solid-phase microextraction and liquid chromatography–mass spectrometry
2007
A new analysis method to detect carbamates and phenylurea pesticide residues in fruit juices was developed using solid-phase microextraction (SPME) coupled with liquid chromatography-single quadrupole mass spectrometry (LC/MS) and liquid chromatography-quadrupole ion trap mass spectrometry (LC/QIT-MS). The pesticide residues present in watery matrices as fruit juices were extracted using three types of fibers: 50-microm Carbowax/templated resin (CW/TPR), 60-mum poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) and 85-microm polyacrylate. The different extraction conditions were evaluated choosing as the best parameters 90 min (time), 20 degrees C (temperature) and 1 ml (volume). After extrac…
Comparison of various liquid chromatographic methods for the analysis of avermectin residues in citrus fruits.
2001
Abstract Various liquid chromatographic (LC) techniques for analyzing avermectin (Abamectin) were compared after extraction of residues from citrus fruit samples by matrix solid-phase dispersion (MSPD). LC with UV and fluorescence detection were used as also was LC coupled to the mass spectrometer by an electrospray interface. The results obtained by the three methods were compared in terms of sensitivity and selectivity. The combination of MSPD extraction and LC with fluorescence detection have made it possible to quantify 0.5 μg kg −1 of Abamectin in 0.5 g of orange sample, with an overall average recovery of 94%. The procedure provides a simple and sensitive method for monitoring Abamect…
Analysis of meat samples for anabolic steroids residues by liquid chromatography/tandem mass spectrometry.
2007
A rapid, specific and highly sensitive multi-residue method for the determination of anabolic steroid residues in bovine, pork and poultry muscle tissues was developed. The sample preparation involves enzymatic digestion followed by extraction with methanol. The crude extract was cleaned up by solid-phase extraction (SPE) combining C18 and NH2 columns. The detection was carried out by a highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method using both positive and negative ionization modes. Natural and synthetic steroids covering different polarities could be extracted, concentrated and purified using one single method. Mobile phase com…
Analysis of enniatins and beauvericin by LC-MS/MS in wheat-based products
2017
Due to the matrix complexity for wheat-based products, a comparative study of different rapid extraction procedures was performed for the extraction of enniatins (ENA, ENA1, ENB, ENB1) and beauvericin in flour, pasta, breakfast cereals, and biscuits. Three different approaches were studied during the extraction and purification steps (shaker, Ultra-Turrax, and QuEChERS) for each matrix. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray source working in a positive mode was used. For the analysis of the five mycotoxins, the three methods were tested in terms of recovery, matrix effect, and sensibility, concluding that Ultra-Turrax extraction was the most …
Preconcentration and speciation of chromium in waters using solid-phase extraction and atomic absorption spectrometry
2000
Abstract A method for the preconcentration and speciation of chromium was developed. After formation of an anionic compound with ethylenediaminetetraacetic acid (CrY − ), Cr (VI) and Cr (III) are retained on a strong anionic phase (SAX) and controlled elution with 0.5 M NaCl permits their speciation. The retention and elution conditions were optimised, and interferences due to the presence of other ions such as Mg(II), Mn(II), Sn(II), Fe(III), Ba(II), Al(III), Ca(II), chloride, iodine, bromide, fluoride, sulphate, phosphate, bicarbonate and nitrate were studied. The detection limits were 0.4 μg l −1 and 1.1 μg l −1 for Cr(III) and Cr(VI), respectively, and reproducibility was 9%. The result…
Green Extraction Strategies for Sea Urchin Waste Valorization
2021
Commonly known as “purple sea urchin,” Paracentrotus lividus occurs in the Mediterranean Sea and the eastern Atlantic Ocean. This species is a highly appreciated food resource and Italy is the main consumer among the European countries. Gonads are the edible part of the animal but they represent only a small fraction (10–30%) of the entire sea urchin mass, therefore, the majority ends up as waste. Recently, an innovative methodology was successfully developed to obtain high-value collagen from sea urchin by-products to be used for tissue engineering. However, tissues used for the collagen extraction are still a small portion of the sea urchin waste (<20%) and the remaining part, main…
A massive lesion detection algorithm in mammography
2004
A new algorithm for massive lesion detection in mammography is presented. The algorithm consists in three main steps : 1) reduction of the dimension of the image to be processed through the identifi cation of regions of interest (rois) as candidates for massive lesions ; 2) characterization of the roi by means of suitable feature extraction ; 3) pattern classifi cation through supervised neural networks. Suspect regions are detected by searching for local maxima of the pixel grey level intensity. A ring of increasing radius, centered on a maximum, is considered until the mean intensity in the ring decreases to a defi ned fraction of the maximum. The rois thus obtained are described by avera…
Sustainability of the Renewable Energy Extraction Close to the Mediterranean Islands
2017
The aim of this work is to explore the possibility of transitioning a fuel powered island to a renewable powered one. This transition is analyzed for the real MV/LV distribution system of the island of Pantelleria, in the Mediterranean Sea. Particularly, this work is focused on a renewable source nowadays totally unused: wave energy. Thanks to the innovative generator prototype designed by Department of Energy of University of Palermo (Italy), wave energy is able to represent a primary source for the production of electric energy in the Mediterranean islands. The procedures applied in the present article, as well as the main equations used, are the result of previous applications made in di…
Land cover classification of VHR airborne images for citrus grove identification
2011
Abstract Managing land resources using remote sensing techniques is becoming a common practice. However, data analysis procedures should satisfy the high accuracy levels demanded by users (public or private companies and governments) in order to be extensively used. This paper presents a multi-stage classification scheme to update the citrus Geographical Information System (GIS) of the Comunidad Valenciana region (Spain). Spain is the first citrus fruit producer in Europe and the fourth in the world. In particular, citrus fruits represent 67% of the agricultural production in this region, with a total production of 4.24 million tons (campaign 2006–2007). The citrus GIS inventory, created in…