Search results for "VOLUME"
showing 10 items of 1932 documents
Development a mitigation strategy of enniatins in pasta under home-cooking conditions
2016
The effect of pasta cooking on the enniatins (ENs) contents was evaluated in white and whole-grain pasta. The cooking of pasta was performed for 10 min in boiling water. ENs were extracted from raw and cooked pasta by Solid-Liquid extraction with acetonitrile, and from cooking water by Dispersive Liquid–Liquid Micro-Extraction (DLLME) with a mixture of acetonitrile and carbone tetrachloride. Mycotoxin analysis was performed by Liquid Chromatography coupled to Tandem Mass Spectrometry. The effect of pasta cooking has a marked influence on the reduction of ENs levels. Reductions of 98–100% for ENA, 94–95% for ENA1, 14–49% for ENB and 53–65% for ENB1 were achieved after the process. ENs were d…
A New Simple Static Method for the Determination of Solubilities of Condensed Compounds in Supercritical Fluids
2002
Abstract A simple static method based on gravimetric measurements has been adopted to measure the solubility of benzenecarboxylic acid, 2-hydroxy-benzenecarboxylic acid, 4-hydroxy-benzenecarboxylic acid and 1,8-dihydroxyanthraquinone along several isotherms in the temperature range 318–357 K and the pressure interval 7–23 MPa. Solubility data have been correlated with the Zieger–Eckert approach, using the Fedor atomic and group contribution method to estimate the solubility parameter and the molar volume of the solutes. A good agreement was obtained between data reported in the literature and those determined using the proposed method which allows one to measure solubility mole fraction as …
Packing technology, column bed structure and chromatographic performance of 1-2-μm non-porous silicas in high-performance liquid chromatography
1989
This work is aimed at further elucidating the aggregation behaviour of micron- and submicron-size non-porous silicas and the column performance of 1–2-μm C18 silicas in reversed-phase high-performance liquid chromatography of low-molecular weight compounds. It is demonstrated that highly ordered, dense, porous aggregates of such silica beads were obtained by gravity settling and centrifugation. The slurry techniques applied at constant flow-rate and a pressure up to 50 MPa provided less-ordered aggregates, but generated an acceptable performance of columns when 1–2-μm C18 silica beads were employed. To operate columns of 53 mm × 4.6 mm I.D., the maximum flow-rate needs to be ca. 2.5 ml/min …
A theoretical plate model accounting for slow kinetics in chromatographic elution.
2011
The chromatographic elution has been studied from different perspectives. However, in spite of the simplicity and evident deficiencies of the plate model proposed by Martin and Synge, it has served as a basis for the characterization of columns up-to-date. This approach envisions the chromatographic column as an arbitrary number of theoretical plates, each of them consisting of identical repeating portions of mobile phase and stationary phase. Solutes partition between both phases, reaching the equilibrium. Mobile phase transference between the theoretical plates is assumed to be infinitesimally stepwise (or continuous), giving rise to the mixing of the solutions in adjacent plates. This yi…
Evaluation of advanced silica packings for the separation of biopolymers by high-perforamnce liquid chromatography
1987
Non-porous monodisperse 1.5-μm silicas were allowed to react with (A) and (B) N-acetylaminopropyltriethoxysilane to generate bonded phases useful in high-performance hydrophobic-interaction chromatography (HIC). Differences in the selectivity were observed between he amide and the ether phase. Peak capacities between 10 and 30 were achieved for several proteins with the amide and ether phase packed into columns of 36 × 8 mm I.D. and elution of the proteins under chromatographic conditions in which the gradient volume, VG, was held constant by varying the gradient time between 20 and 2.5 min and the flow-rate between 0.5 and 4.0 ml/min. The S values derived from the dependences of log k′ on …
Experimental and fluid dynamic study of continuous supercritical water gasification of glucose
2016
Abstract The supercritical water gasification (SCWG) of glucose as a model compound for H 2 production is studied in term of process development at 25 MPa and 650 °C. Gasification has been investigated using a laboratory scale continuous plant comprising a continuous down flow reactor with a volume of 200 cm 3 , a heat recovery section and pre-heat of the biomass to simulate more closely an industrial design. Feed streams (pure water and glucose solution) are introduced at the top of the vessel and products are extracted from the bottom. The reactor is equipped with various inlet points that allow to modify the inlet position of reacting streams in order to study the effect of stream mixing…
Densities, Viscosities, and Refractive Indices of Some Binary Liquid Systems of Methanol + Isomers of Hexanol at 298.15 K
1996
Viscosities, densities, and refractive indices of eight binary liquid systems containing ethanol + some isomers of hexanol have been determined at 298.15 K. The excess property values were fitted to the Redlich-Kister equation to estimate the binary coefficients and the standard deviations.
Enhanced styrene removal in a two-phase partitioning bioreactor operated as a biotrickling filter: Towards full-scale applications
2017
Abstract Styrene vapor abatement was investigated in a two-phase partitioning bioreactor operated as a biotrickling filter (TPPB-BTF). The removal performance of the TPPB-BTF was simultaneously compared with a conventional BTF, which served as a control. Industrial-grade silicone oil was used as the non-aqueous phase in the TPPB-BTF due to its high affinity for styrene. Both bioreactors were operated at styrene inlet concentrations ranging from 55 to 323 mg C m −3 and empty bed residence times (EBRT) of 15–30 s, corresponding to pollutant loading rates of 13–77 g C m −3 h −1 . Both bioreactors exhibited styrene removal efficiencies (REs) higher than 90% at an EBRT of 30 s. Nevertheless, th…
Volumes and compressibilities of pentanol in aqueous alkyltrimethylammonium bromide solutions at different temperatures
1990
Speed of sound and density properties of ternary water-tetradecyltrimethylammonium bromide-pentanol system at 15, 25 and 35°C and of water-hexadecyltrimethylammonium bromide-pentanol system at 25, 35 and 45°C were measured at fixed alcohol concentration as a function of surfactant concentration. The apparent molar volumes Vϕ,R and isentropic compressibilities Kϕ,RS of pentanol in micellar solutions as a function of the surfactant concentration show irregular behavior which depends on the alkyl chain length of the surfactant and tends to disappear with increasing temperature. These anomalies are ascribed to micellar transitions. For both surfactants at high concentrations, Vϕ,R decrease and …
Error analysis and performance of different retention models in the transference of data from/to isocratic/gradient elution.
2003
The transferability of retention data among isocratic and gradient RPLC elution modes is studied. For this purpose, 16 beta-blockers were chromatographed under both isocratic and gradient elution with acetonitrile-water mobile phases. Taking into account the elution mode where the experimental data come from, and the mode where the retention should be predicted, the following combinations are possible: isocratic predictions from (i) isocratic or (ii) gradient experimental designs; and gradient predictions from (iii) isocratic or (iv) gradient data. Each of these possibilities was checked using three retention models that relate the logarithm of the retention factor: (a) linearly and (b) qua…