Download or read book Preparation and characterization of well defined chemically bonded stationary phase for high pressure liquid chromatography written by Gerrit Engbertus Berendsen and published by . This book was released on 1980 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Well defined Chemically Bonded Stationary Phases for High Pressure Liquid Chromatography written by Gerrit Engbertus Berendsen and published by . This book was released on 1980 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book THE CHARACTERIZATION OF BONDED PHASES FOR HIGH PERFORMANCE LIQUID CHROMATOGRAPHY written by and published by . This book was released on 1980 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physical and chemical nature of chemically bonded phases used in high performance liquid chromatography have been studied. These bonded phases were characterized by a variety of chromotographic and non-chromatographic experiments. The non-chromatographic techniques included 13C NMR and batch extraction methods. The role played by the bonded phase as well as the mobile phase in determining the retention characteristics of the "stationary phase" were determined. The retention of solute molecules on bonded phases was found to be a function of the chain length of the bonded phase, the chemical nature of the bonded molecule, and the type of organic modifier used in the mobile phase. The energetics of the solute-stationary phase interactions was determined by the differential enthalpy and was found to be indicative of a partitioning process between two liquid phases. The retention process was also affected by the surface coverage of the bonded molecule. Optimum retention and separation characteristics were obtained with a hydrocarbon bonded phase of high surface coverage when used with a mobile phase containing a very polar organic modifier. The efficiency of these bonded phases was found to be independent of chain length as well as surface coverage of the bonded molecule. Some bonded phases which have specific functionalities incorporated into the bonded molecule are not true reversed phases. The selectivity of the bonded phases towards polar solute molecules was found to be affected by the type of organic modifier used in the mobile phase. The major accomplishment of this work shows that the stationary phase consists of the bonded molecule as well as trapped mobile phase. The composition of this ternary mixture is a function of the type and amount of bonded material and the type and amount of organic modifier used in the mobile phase
Download or read book Bonded Stationary Phases in Chromatography written by Eli Grushka and published by . This book was released on 1974 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Multifunctional Stationary Phases for Multimode Separations written by Asanka Wijekoon and published by . This book was released on 2010 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: High performance liquid chromatography is a powerful analytical technique employed to separate analyte mixtures. Since biomedical sample mixtures contain a very diverse range of compounds; one chromatographic mode is usually unable to separate all components of the mixture. Therefore, there is an increasing need for faster and efficient separations with a broad range of selectivity. To attain better selectivity and efficient separation, and to improve the versatility of the chromatographic column, a new way of preparation of multifunctional stationary phases, suitable for use in multiple chromatographic separation modes, is described. The preparation of multifunctional stationary phases takes advantage of Schiff base chemistry in two different synthetic routes. The first route involves reductive coupling of amino bonded silica with aldehyde containing ligands. The coupling of aldehyde bonded silica with amine containing ligands is the other reaction route. Aldehyde terminated silica is a versatile reactive platform that enables the synthesis of a wide range of stationary phases by attaching amine containing ligands that have diverse functionality. Here the preparation of aldehyde terminated silica was achieved by bonding aldehyde silane to the silica surface. Preparation of aldehyde silane is a novel approach and a successful synthetic scheme of making acetalated aromatic aldehyde silane (AAS- Aldehyde group in the silane has been protected by acetalation) and aromatic aldehyde silane (AS) is invented. The studies confirmed that the synthesized multifunctional chromatographic stationary phases were capable of operating in ion exchange mode, reversed phase mode and hydrophilic interaction liquid chromatographic mode. The studies further concluded that those surfaces have good selectivity for the separation of small polar and charge molecules. The application of the well established Schiff base reaction allowed the incorporation 2H to the bonded phases and is utilized to study the motional dynamics of the bonded ligands in the surface at different temperatures in the presence of a broad range of solvent systems by using 2H wide line NMR spectroscopy. The investigation provides information about the motional dynamic heterogeneity of the bonded ligands, which reflects the existence of surface heterogeneity of the surface.
Download or read book Preparation and characterization of written by Emad Yousif and published by LAP Lambert Academic Publishing. This book was released on 2012 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: New stationary phase for high performance liquid chromatography had been prepared by the reaction of congo red solution with amberlite anion exchange. The F.T.I.R elemental analyses have configured the attachment of congo red on the resin as has indicated by the physical appearance of the new resin. The resin capacities of newly prepared resin has calculated the resin capacity for the amberlite-congo red resin was found to average 4.8 meq/ gm and for the amberlite resin 3.0 meq./gm. The new stationary phase has been packed into stainless steel column. This has been done by the special teqnique. The chromatographic performance of the packed column was characterized the number of plate numbers, height equivalent of a theoretical plates, capacity factors, selectivity factor and peak asymmetry were measured by analyzing different analysis on the new column using different mobile phases composition and flow rates. The parameters were measured from analasisi of some amino acids such as histidine, phenyl alanine, tyrosine and prolenene. The analysis of amino acids using amberlite-congo red column has performed with an aqueous mobile phase adjusted at pH 2.5.
Download or read book Recent Advances in Synthesis Characterization and Applications of Chemically Bonded Phases written by Mietek Jaroniec and published by . This book was released on 1996 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Bonded Stationary Phases in High Performance Liquid Chromatography written by Steven Douglas Fazio and published by . This book was released on 1985 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Diphenylphosphine Bonded Phase Packings for High Performance Liquid Chromatography written by Tyra L. Montgomery and published by . This book was released on 1984 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Reversed Phase Stationary Phases for High Performance Liquid Chromatography written by Karen Wink Barnes and published by . This book was released on 1986 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reversed phase liquid chromatography (RPLC) is a widely used separation technique today. The stationary phase, composed of hydrocarbon moieties chemically bound to a silica support, is commonly prepared by refluxing the silica with a reactive silane in an appropriate solvent. Siloxane bonds, Si-O-Si, are formed. There are limitations to RPLC in that nonhomogeneous surface coverages, detrimental to efficient separations, result from the bonding process, and because the reaction is never complete due to steric restrictions. Also, silica is soluble at high pH values, and the Si-C bond binding the hydrocarbon to the silica is labile at low pH ranges. Thus, the usable pH range for silica stationary phases is 2.5 to 7.5, and often this range is too narrow to allow the separation of a mixture. The use of ultrasonic cavitation to catalyze silane bonding was investigated to dtermine whether the vigorous ultrasonic process would drive reagents into the surface pores and better distribute the hydrocar bonaceous reagent, thereby producing a more efficient stationary phase. Tandem reactions proved that ultrasonic bonding procedures are as effective as the refluxed, and that the chromatographic efficiency of the ultrasonic phases was comparable, if not superior, to the refluxed. Chromatographic tests also indicated the ultrasonic phases were comparable to commercially available phases. The reproducibility of the reactions and the effect of acoustic power and heat were also investigated. A second set of experiments investigated substitution of alumina for silica because the alumina crystalline structure remains intact over a pH range of 2 to 12. A trifunctional modification scheme generating a thick cross-linked hydrocarbon matte was used because the Al-0 bond is susceptible to hydrolysis, which strips the bound hydrocarbons, by polar RP solvents. Five aluminas were bonded and tested for chromatographic utility. Reaction conditions were optimized, and ultrasonic bonding was investigated. It was found that alumina with a sufficiently active surface is modifiable, and that the modified surface is remarkably stable for use with acidic and basic buffers and in neutral, polar solvent mixtures. The chromatographic utility of alumina phases was demonstrated and compared with the silica results.
Download or read book A Chromatographic and Spectroscopic Characterization of Chemically Bonded Stationary Phases written by Darrel R. Wilder and published by . This book was released on 1980 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High speed Liquid Chromatography written by Peter M. Rajcsanyi and published by . This book was released on 1975 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stationary Phases in Gas Chromatography written by H. Rotzsche and published by Elsevier. This book was released on 1991-08-21 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary aim of this volume is to make the chemist familiar with the numerous stationary phases and column types, with their advantages and disadvantages, to help in the selection of the most suitable phase for the type of analytes under study. The book also provides detailed information on the chemical structure, physico-chemical behaviour, experimental applicability, physical data of liquid and solid stationary phases and solid supports. Such data were previously scattered throughout the literature. To understand the processes occurring in the separation column and to offer a manual both to the beginner and to the experienced chromatographer, one chapter is devoted to the basic theoretical aspects. Further, as the effectiveness of the stationary phase can only be considered in relation to the column type, a chapter on different column types and the arrangement of the stationary phase within the column is included. The secondary aim of this book is to stimulate the development of new and improved standardized stationary phases and columns, in order to improve the reproducibility of separations, as well as the range of applications.
Download or read book The Synthesis and Characterization of Homopolypeptide Bonded Stationary Phases for Liquid Chromatography written by Barbara Ann Siles and published by . This book was released on 1993 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Characterization of Bonded Phases for High Performance Liquid Chromatography written by Klaus John Stetzenbach and published by . This book was released on 1980 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High pressure Liquid Chromatography A Brief Introduction and Its Application in Analyzing the Degradation of a C ether Thio ether Liquid Lubricant written by and published by . This book was released on 1983 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Bonded Zwitterionic Stationary Phases for High Performance Liquid Chromatography written by Louis W. Yu and published by . This book was released on 1987 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
