Search results for "VOLUME"
showing 10 items of 1932 documents
Miniature diamond-anvil cells for FTIR-microspectroscopy of small quantities of biosamples.
2018
Fourier transform infrared (FTIR) spectroscopy techniques and data analyses have become widely available, are easy to use, and are convenient for studies of various biosamples, especially in biomedical science. Yet, cultivation of cells and purification of cell components are costly, often methodically challenging, and time and labor consuming. Therefore, reduction of the sample amount is of high value. Here we propose a novel method for the analysis of small quantities of biosamples by FTIR-microscopy of dry films using a diamond-anvil cell (DAC). This approach allows us to decrease the sample volume at least a hundred times compared to that for a high-throughput screening device (HTS-XT, …
Pleurotus ostreatus volatile aroma compounds identified from fruit-body and from mycelium grown in submerged and solid-state cultures
2003
Comparative analyses of volatile aroma compounds of the Pleurotus ostreatus JMO.95 fruit-body and its corresponding mycelium grown in liquid, on agar surface, or on solid support cultures have been carried out by dynamic headspace concentration using GC/MS and GC/sniffing. The aroma of the fruit-body was due essentially to the presence of octan-3-one and, in a lesser extent, to the presence of octan-3-ol. Other compounds, such as oct-l-en-3-ol, oct-l-en, 2-methylbutanol and a-pinene were also present in low concentrations. The comparison of the aromatic spectra of the fruit-body with the aromatic spectra of mycelia obtained under different culture conditions indicated that the main aromatic…
CO2 conversion in a photocatalytic continuous membrane reactor
2016
The reduction of CO2 with water by using photocatalysts is one of the most promising new methods for achieving CO2 conversion to valuable hydrocarbons such as methanol (MeOH). In this work, prepared TiO2-Nafion (TM)-based membranes were used in a photocatalytic membrane reactor, operated in continuous mode, for converting CO2 to methanol. By using the membrane with the best TiO2 distribution, a MeOH flow rate/TiO2 weight of 45 mu mol (g(catalyst) h)(-1) was measured when operating at 2 bar of feed pressure. This value is higher than those reported in most of the literature data to date. Moreover, methanol production is considered as a relevant advance over the existing literature results wh…
Application of microwaves dielectric spectroscopy for controlling pork meat (Longissimus dorsi) salting process
2010
Abstract Salting treatment is a common operation in the production of high quality meat products, one of its main problems is the difficulty to control the simultaneous water and salt fluxes into the product and control the protein fibers transformation throughout process. Dielectric properties of salted porcine meat are strongly related to its structure and composition. Thus, dielectric properties measurement appears as a promising method for controlling on-line the salting process in meat industry. Dielectric spectroscopy studies have been performed on raw and salted Longissimus dorsi pork samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilen…
Interpretive optimisation of organic solvent content and flow-rate in the separation of β-blockers with a Chromolith RP-18e column
2009
The chromatographic performance of a Chromolith RP-18e column was comprehensively examined for a group of basic drugs (beta-blockers), eluted with isocratic ACN-water mixtures at increasing flow-rate up to 6 mL/min. As the flow-rate increases at fixed mobile phase composition, peak distribution (selectivity) is maintained, but the relative peak widths increase. This reduces the resolution below satisfactory values for closely eluting compounds. With the monolithic column, flow-rate becomes thus an important factor to be optimised, in addition to the mobile phase composition. Since, theoretically, retention factors (k) are independent of the flow-rate, the classical quadratic model relating …
Impact of pore structural parameters on column performance and resolution of reversed-phase monolithic silica columns for peptides and proteins
2007
In this work, monolithic silica columns with the C4, C8, and C18 chemistry and having various macropore diameters and two different mesopore diameters are studied to access the differences in the column efficiency under isocratic elution conditions and the resolution of selected peptide pairs under reversed-phase gradient elution conditions for the separation of peptides and proteins. The columns with the pore structural characteristics that provided the most efficient separations are then employed to optimize the conditions of a gradient separation of a model mixture of peptides and proteins based on surface chemistry, gradient time, volumetric flow rate, and acetonitrile concentration. Bo…
Isolation and concentration of organophosphorus pesticides from water using a c18 reversed phase
1989
Abstract A simple, rapid and effective method for the extraction and enrichment of organophosphorus pesticides based on the use of Sep-Pak C 18 cartridges was studied as alternative method to those based on extraction with organic solvents. The influence of the elution solvent, pH, salinity and volume of water filtered was studied for ten organophosphorus pesticides. The pesticides were determined by gas chromatography with a BP-1 capillary column and a thermionic detector. Recoveries at the 100 and 200 ng/1 spiking levels were greater than 85%, except for disulfoton.
Electron paramagnetic resonance (EPR) spin trapping of biological nitric oxide
2007
Nitric oxide (NO) is a free radical species with multiple physiological functions. Because of low concentrations and short half-life of NO, its direct measurement in living tissues remains a difficult task. Electron paramagnetic resonance (EPR) spin trapping is probably one of the best suitable platforms for development of new methods for quantification of biological NO. The most reliable EPR-based approaches developed so far are based on the reaction of NO with various iron complexes, both intrinsic and exogenously applied. This review is focused on the current state and perspectives of EPR spin trapping for experimental and clinical NO biology.
Study on the efficiency of assembled packed microbore columns in HPLC
1984
Stainless steel columns (internally mirror-finished, 125 or 250nm in length, of bore 1.0 or 1.6mm) were slurry-packed with 5µm and 4µm reversed phase silicas (Hypersil ODS, LiChrosorb RP-8 and RP-18 and Superspher RP-8. The HPLC equipment consisted of a pump LC5A (Shimadzu) or a pump 2150 (LKB Instruments), a rheodyne valve 7413 with loops of 0.5, 1.0 and 5.0mm3 and a Jasco-Uvidec 100-II UV detector, variously with one of three specially constructed cells of 0.2, 0.4 and 1.3mm3 volume. Columns were assembled using two types of coupling device employing a stainless steel capillary of 0.12mm bore. The effect of sample volume, design of coupling device in assembled column, detector cell volume…
Ein automatisches viskosimeter zur flüssigkeitschromatographie
1968
Eine Viskosimeterapparatur wird beschrieben, die ein automatisches sukzessives Einfullen und Meessen von Flussigkeiten erlaubt. Bei chromatographischen Prozessen ermoglicht es das Gerat, auser der bisher ublichen Verfolgung der Konzentration auch das Molekulargewicht des gelosten Stoffes im Eluat zu bestimmen. Fur eine Elutionsgeschwindigkeit von 1 ml/min ist es moglich, das mittlere viskosimetrische Molekulargewicht in Intervallen von jeweils 2 ml oder auch 1 ml fur den gesamten Elutionsvorgang anzugeben. A viscometer system is described, which allows automatic successive loading and measuring of liquids. For chromatographic columns the apparatus can registrate not only the concentration b…