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Mass Separation (mass + separation)
Selected AbstractsTICL , a web tool for network-based interpretation of compound lists inferred by high-throughput metabolomicsFEBS JOURNAL, Issue 7 2009Alexey V. Antonov High-throughput metabolomics is a dynamically developing technology that enables the mass separation of complex mixtures at very high resolution. Metabolic profiling has begun to be widely used in clinical research to study the molecular mechanisms of complex cell disorders. Similar to transcriptomics, which is capable of detecting genes at differential states, metabolomics is able to deliver a list of compounds differentially present between explored cell physiological conditions. The bioinformatics challenge lies in a statistically valid interpretation of the functional context for identified sets of metabolites. Here, we present TICL, a web tool for the automatic interpretation of lists of compounds. The major advance of TICL is that it not only provides a model of possible compound transformations related to the input list, but also implements a robust statistical framework to estimate the significance of the inferred model. The TICL web tool is freely accessible at http://mips.helmholtz-muenchen.de/proj/cmp. [source] Investigation into the protein composition of human tear fluid using centrifugal filters and drop coating deposition Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2009Jacob Filik Abstract Drop coating deposition Raman spectroscopy (DCDRS) is a simple method of analysing weak protein solutions. This study is another step in evaluating the analysis of tear fluid by DCDRS as a future medical diagnostic technique. The main aims of this study are to determine whether the DCDR spectra from tear samples contain signals from more than one protein (so relative levels can be measured) and, if so, are the proteins homogeneously distributed in the dried ring of the deposited material. Tear samples were collected from four healthy volunteers and pooled prior to analysis. Proteins were separated by mass into three groups using centrifugal filters. These groups contained proteins with (1) masses greater than 100 kDa, (2) masses between 100 and 50 kDa and (3) masses between 50 and 3 kDa. DCDR spectra from each of these protein group solutions displayed significant differences, confirming that the mass separation had been successful. When used as basis vectors for least-squares fitting, these spectra (and that of urea) produced excellent fits to the normal tear spectra. Least-squares fitting of spectra from the same point on a single sample and from several drops of the same sample showed that the tear DCDR spectra were highly reproducible. Raman point mapping of the tear ring showed significant radial ring variation, especially towards the outer edge of the ring. The specific peak changes in the protein signal across the ring suggested that the difference in the outer edge was due to protein desiccation as opposed to inhomogeneous protein deposition. Copyright © 2008 John Wiley & Sons, Ltd. [source] HPLC/ESI-MSn and ESI-MS studies on the Aconitum alkaloids in three Chinese medicinal herbsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17-18 2010Wenlong Liu Abstract Aconitum lipo-alkaloids (LDAs) peaks in the previous HPLC studies have shown overlapping behavior, making it impossible to identify the total retention behavior of LDAs. The structural diversity of LDAs in Radix Aconiti, Radix Aconiti Kusnezoffii and Radix Aconiti Lateralis Preparata makes it difficult to synthesize and quantify each of them. Therefore, this study has been devoted to develop a HPLC/ESI-MSn method with good resolution of Aconitum alkaloids especially LDAs and then set up a fast ESI-MS SIM method to quantify the total contents of specific skeleton LDAs in the three herbs via in-source CID and the capability of mass separation. As a result, the retention behavior of LDAs was summarized based on an optimized chromatographic separation; 32 alkaloids from the three herbs of Aconitum genus were separated and identified according to their fragmentation pathways by using HPLC/ESI-MSn. In addition, a fast quantitative analysis ESI-MS SIM method was successfully applied to the quantification of the total contents of specific skeleton LDAs in the three herbs. [source] Imaging mass spectrometry for examining localization of polymeric composition in matrix-assisted laser desorption/ionization samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2009Steffen M. Weidner The localization of polymeric composition in samples prepared for matrix-assisted laser desorption/ionization (MALDI) analysis has been investigated by imaging mass spectrometry. Various matrices and solvents were used for sample spot preparation of a polybutyleneglycol (PBG 1000). It was shown that in visibly homogeneous spots, prepared using the ,dried droplet' method, separation between matrix and polymer takes place. Moreover, using , -cyano-4-hydroxycinnamic acid (CCA) as matrix and methanol as solvent molecular mass separation of the polymer homologues in the spots was detectable. In contrast to manually spotted samples, dry spray deposition results in homogeneous layers showing no separation effects. Copyright © 2009 John Wiley & Sons, Ltd. [source] A mass filter based on an accelerating traveling waveRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2008Michael Wiedenbeck We describe a novel mass filtering concept based on the acceleration of a pulsed ion beam through a stack of electrostatic plates. A precisely controlled traveling wave generated within such an ion guide will induce a mass-selective ion acceleration, with mass separation ultimately accomplished via a simple energy-filtering system. Crucial for successful filtering is that the velocity with which the traveling wave passes through the ion guide must be dynamically controlled in order to accommodate the acceleration of the target ion species. Mass selection is determined by the velocity and acceleration with which the wave traverses the ion guide, whereby the target species will acquire a higher kinetic energy than all other lighter as well as heaver species. Finite element simulations of this design demonstrate that for small masses a mass resolution M/,M,,,1000 can be achieved within an electrode stack containing as few as 20 plates. Some of the possible advantages and drawbacks which distinguish this concept from established mass spectrometric technologies are discussed. Copyright © 2008 John Wiley & Sons, Ltd. [source] State of the Art Pump Technology for Reverse Osmosis SystemsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2003R. Schmitz The industrial significance of diaphragm processes in mass separation is ever increasing; this is particularly true for the use of reverse osmosis (RO) and related methods. Decisive factors for the economy of RO processes, and thus for the future of this technology, are the reliability and energy consumption of the high-pressure pumps involved. Current pump developments reflect clear progress in this field. [source] | ||||||||||