Search results for "Extraction"
showing 10 items of 2072 documents
Silymarin compounds: Chemistry, innovative extraction techniques and synthesis
2020
Abstract Silymarin complex consisting of four flavonolignans (silychristin, silydianin, silibinin and taxifolin) has been used from ancient times in both traditional European and Asian medicine for liver disorders treatment. Moreover, over the last years, the anticancer activity of these compounds against various types of cancer cells (e.g., breast, skin, colon, cervix, ovary, prostate, lung and hepatocellular cancers, among others) has been demonstrated. Therefore, at this stage of development, food and pharmaceutical interest have shown an increased interested in the recovery of these molecules. Conventional solvent extraction has been traditionally used to recover silymarin complex from …
Feasibility and application of solvent assisted flavour evaporation and standard addition method to quantify the aroma compounds in flavoured baked m…
2006
International audience; In order to determine the feasibility of the solvent assisted flavour evaporation extraction (SAFE) technique and the standard addition method to quantify the aroma compounds retained in baked matrices after processing, three doughs that mainly vary in one ingredient, M1 (with eggs and palm oil), M2 (without eggs but with palm oil) and M3 (without eggs and without palm oil) were flavoured with an aromatic formulation of 19 different aroma compounds in propylene glycol that is responsible for a viennoiserie aromatic note. From the 19 aroma compounds added, 12 of them were quantified, so was also the propylene glycol. After the application of standard addition method 3…
Determination of essential metals in complete diet feed by flow injection and flame atomic absorption spectrometry
2002
A prior study of different sample pre-treatments for the determination of metallic elements in complete diet feeds was performed in order to choose the most suitable for these samples. The studied pre-treatment were: acid extraction (lixiviation), wet digestion (on microwave oven) and dry ashing mineralization (calcination). Lixiviation (acid extraction) with hydrochloric acid was selected due to its accuracy, fast and simple pre-treatment procedure. Due of the different levels of concentration of the metallic elements in the samples, the same manifold was used but with small variations. Copper (with on-line pre-concentration by chelating Chelex-100 resin), calcium (with on-line dilution) a…
Fourier transform infrared spectrometric strategies for the determination of Buprofezin in pesticide formulations
2002
Abstract Two different strategies for Buprofezin determination, an off-line extraction and stopped-flow determination and an automated procedure, based on the on-line extraction of Buprofezin samples with chloroform and flowing action analysis–fourier transform infrared (FIA–FT-IR) spectrometric measurement of the extracts, have been developed. For the treatment of the off-line extraction mode, data a three-factor partial least squares (PLSs) calibration was developed, using the region from 1465.7 to 1342.3 cm−1 with a single point baseline defined at 2051.9 cm−1 and based on the use of chloroform solutions of Buprofezin. The method provides a R.S.D. On the other hand, the recommended FIA m…
Flow injection-FTIR determination of dithiocarbamate pesticides
2000
A flow injection Fourier transform infrared spectrometric procedure has been developed for the determination the dithiocarbamate pesticides Ziram and Thiram in solid samples. All the operations involved, such as extraction, filtration and measurement, were integrated in the experimental set-up in order to avoid excessive manipulation of samples and standards. Ultrasonic assisted and mechanical extraction were evaluated for the solubilization of the analytes and, additionally, the effect of carrier flow rate, sample loop volume and the ratio between sample mass and volume of solvent employed were studied. Quantitative extractions with chloroform were obtained for both Ziram and Thiram, after…
Flow Injection Analysis– F ourier Transform Infrared Spectrometry ( FIA / FT ‐ IR )
2001
The sections in this article are Advantages and Historical Perspective of the Use of FIA in FT-IR Direct Analysis of Samples by FIA/FT-IR FIA/FT-IR Determinations after Liquid Extraction FIA/FT-IR Determinations after Solid-Phase Extraction Enzymatic Analysis by FIA/FT-IR Vapor Generation FT-IR New Developments
FTIR approaches for diuron determination in commercial pesticide formulations.
2005
Two strategies have been developed for Diuron determination by FTIR spectrometry, an off-line extraction and stopped-flow determination and a fully mechanized procedure, based on the on-line extraction of Diuron and FIA-FTIR measurement of the extracts. The aforementioned procedures have been compared with a reference chromatographic method. The off-line FTIR spectra were obtained at a nominal resolution of 4 cm(-1) from 4000 to 900 cm(-1) by accumulating 25 scans. Diuron was determined using peak height measurements at 1582 cm(-1) corrected using a baseline defined between 1562 and 1614 cm(-1). The waste generation of the off-line procedure was 3.4 mL chloroform for each sample, and the me…
Determination of levamisole hydrochloride with HgI(2-)4 by a turbidimetric method and flow-injection analysis.
1986
Abstract This paper is concerned with the use of ion-association compounds in the analysis of pharmaceutical samples by FIA. The usual extraction into an organic phase is avoided by using turbidimetric detection. Determination of levamisole with HgI2−4 has been developed as a practical example: the experimental variables were optimized by the modified simplex method. The calibration graph is linear over the levamisole concentration range 7–32 μ g ml . The reproducibility (rsd) and injection sample rate are 0.9% and 80/hr, respectively.
Hard Cap Espresso Machines in Analytical Chemistry: What Else?
2016
A hard cap espresso machine has been used in combination with liquid chromatography with molecular fluorescence detection for the determination of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils and sediments providing appropriate extraction efficiencies and quantitative results. Naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benz[b]fluoranthene, benz[k]fluoranthene, benz[a]pyrene, dibenz[a,h]anthracene, benz[ghi]perylene, and indeno[1,2,3-cd]pyrene were used as target compounds. It should be mentioned that the pairs benz[a]anthracene-chrysene and dibenz[a,h]anthracene-benz[ghi]perylene peaks coelute under th…
Sensitive determination of polycyclic aromatic hydrocarbons in water samples using monolithic capillary solid-phase extraction and on-line thermal de…
2011
A methacrylate-based monolithic capillary column has been evaluated for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. For this purpose, the monolyte was in situ synthesized in a 6cm×0.32mm id fused-silica capillary. The microextraction unit was fitted to a micro-HPLC pump to pass 10mL of sample. The isolated pollutants were eluted by means of 10μL of methanol, the organic phase being directly collected in a specific interface that can be fitted to the injection port of the gas chromatograph without modification. The interface allows the on-line thermal desorption of the PAHs, avoiding the dilution and providing enough sensitivity to reach …