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Separation Capabilities (separation + capability)
Selected AbstractsMultifunctional Microporous MOFs Exhibiting Gas/Hydrocarbon Adsorption Selectivity, Separation Capability and Three-Dimensional Magnetic Ordering,ADVANCED FUNCTIONAL MATERIALS, Issue 15 2008Kunhao Li Abstract Microporous materials [M3(HCOO)6],·,DMF (M,=,Mn, Co, Ni) were synthesized solvothermally and structurally characterized by single crystal and powder X-ray diffraction methods. The metal network exhibits diamondoid connectivity and the overall framework gives rise to zigzag channels along the b axis where guest dimethylformamide molecules reside. The effective pore size of these channels is ,5,6,Å. The materials feature high thermal stability and permanent porosity with relatively small pore diameters which are attributed to the extensive strong dative bonding between the metal centers and formate molecules. The title compounds exhibit interesting multi-fold gas adsorption and magnetic properties. The adsorption study of a series of alcohols, aromatics, and linear hydrocarbons revealed strong control of the adsorbent channel structures on their adsorption capacity and selectivity. The study also indicated possibility of using these materials for separation of close boiling chemicals (e.g., ethylbenzene and p-xylene) via pressure swing adsorption (PSA) process and molecules with different diffusion parameters via kinetic-based process. Three-dimensional spontaneous magnetic ordering was found in all three network structures investigated and at ground states they behave somewhat like soft magnets. [source] Selectivity tuning of cyclodextrin derivatives by specific substitutionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2003Melanie Junge Abstract A new, highly enantioselective cyclodextrin derivative combining the properties of heptakis(6- O - tert -butyldimethylsilyl-2,3-di- O -methyl)-,-cyclodextrin and heptakis(2,3-di- O -acetyl-6- O - tert -butyldimethylsilyl)-,-cyclodextrin was prepared by exchanging a methyl group for an acetyl substituent in a single glucose unit of heptakis(6- O - tert -butyldimethylsilyl-2,3-di- O -methyl)-,-cyclodextrin. A comparative evaluation of the separation capabilities showed that the enantioselectivity of both "parent" cyclodextrin derivatives is transferred to the new chiral stationary phase. [source] Novel cinchona carbamate selectors with complementary enantioseparation characteristics for N-acylated amino acidsCHIRALITY, Issue S1 2003Karl Heinz Krawinkler Abstract The synthesis and chromatographic evaluation of the enantiomer separation capabilities of covalently immobilized calix[4]arene-cinchona carbamate hybrid type receptors derived from quinine (QN) and its corresponding C9-epimer (eQN) in different solvents are reported. The receptors display complementary enantiomer separation profiles in terms of elution order, chiral substrate specificity, and mobile phase characteristics, indicating the existence of two distinct chiral recognition mechanisms. The QN-derived receptor binds the (S)-enantiomers of N-acylated amino acids more strongly, shows preferential recognition of open-chained amino acids, and superior enantioselectivity in polar media such as methanol/acetic acid. In contrast, the eQN congener preferentially recognizes the corresponding (R)-enantiomers, displays good enantioselectivity (, up to 1.74) for cyclic amino acids, and enhanced stereodiscriminating properties in apolar mobile phases, e.g., chloroform/acetic acid. A comparison of the enantiomer separation profiles with those of the corresponding QN and eQN tert -butyl carbamate congeners indicates no significant level of cooperativity between the calix[4]arene module and the cinchona units in terms of overall chiral recognition, most probably as a consequence of residual conformational flexibility of the calixarene module and the carbamate linkage. Chirality 15:S17,S29, 2003. © 2003 Wiley-Liss, Inc. [source] Analysis of nuclear proteome in C57 mouse liver tissue by a nano-flow 2-D-LC,ESI-MS/MS approachJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2006Jie Zhang Abstract The analysis of whole cell or tissue extracts is too complex for current protein identification technology and not suitable for the study of proteins with low copy levels. To concentrate and enrich low abundance proteins, organelle proteomics is a promising strategy. This approach can not only reduce the protein sample complexity but also provide information about protein location in cells, organs, or tissues under analysis. Nano-flow two-dimensional strong-cation exchange chromatography (SCX),RPLC,ESI-MS/MS is an ideal platform for analyzing organelle extracts because of its advantages of sample non-bias, low amounts of sample required, powerful separation capability, and high detection sensitivity. In this study, we apply nano-scale multidimensional protein identification technology to the analysis of C57 mouse liver nuclear proteins. Organelle isolation has been optimized to obtain highly pure nuclei. Evaluation of nucleus integrity and purity has been performed to demonstrate the effectiveness of the optimized isolation procedure. The extracted nuclear proteins were identified by five independent nano-flow on-line SCX,RPLC,ESI-MS/MS analyses to improve the proteome coverage. Finally, a total of 462 proteins were identified. Corresponding analyses of protein molecular mass and pI distribution and biological function categorization have been undertaken to further validate our identification strategy. [source] An integrated serum proteomic approach capable of monitoring the low molecular weight proteome with sequencing of intermediate to large peptidesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Karen Merrell The low-abundance, low molecular weight serum proteome has high potential for the discovery of new biomarkers using mass spectrometry (MS). Because the serum proteome is large and complex, defining relative quantitative differences for a molecular species between comparison groups requires an approach with robust separation capability, high sensitivity, as well as high mass resolution. Capillary liquid chromatography (cLC)/MS provides both the necessary separation technique and the sensitivity to observe many low-abundance peptides. Subsequent identification of potential serum peptide biomarkers observed in the cLC/MS step can in principle be accomplished by in series cLC/MS/MS without further sample preparation or additional instrumentation. In this report a novel cLC/MS/MS method for peptide sequencing is described that surpasses previously reported size limits for amino acid sequencing accomplished by collisional fragmentation using a tandem time-of-flight MS instrument. As a demonstration of the approach, two low-abundance peptides with masses of ,4000,5000,Da were selected for MS/MS sequencing. The multi-channel analyzer (MCA) was used in a novel way that allowed for summation of 120 fragmentation spectra for each of several customized collision energies, providing more thorough fragmentation coverage of each peptide with improved signal to noise. The peak list from this composite analysis was submitted to Mascot for identification. The two index peptides, 4279,Da and 5061,Da, were successfully identified. The peptides were a 39 amino acid immunoglobulin G heavy chain variable region fragment and a 47 amino acid fibrin alpha isoform C-terminal fragment. The method described here provides the ability both to survey thousands of serum molecules and to couple that with markedly enhanced cLC/MS/MS peptide sequencing capabilities, providing a promising technique for serum biomarker discovery. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||