Download or read book Synthesis and Characterization of a New Chemically Bonded Liquid Crystal Stationary Phase for HPLC written by Sheela Muley and published by . This book was released on 1999 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Characterization of Bonded Liquid Crystal Stationary Phases for Use in High Performance Liquid Chromatography written by Mark Allen Vidensek and published by . This book was released on 1990 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Characterization of a Novel Liquid Crystal Stationary Phase for HPLC written by Christine A. Kenny and published by . This book was released on 1999 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Synthesis and Characterization of Liquid Crystal like Stationary Phases for High Performance Liquid Chromatography written by Zhuxu Wang and published by . This book was released on 1995 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of New Bonded Stationary Phases for HPLC written by Deepika Janga and published by . This book was released on 2004 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Essentials in Modern HPLC Separations written by Serban C. Moldoveanu and published by Elsevier. This book was released on 2022-06-24 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essentials in Modern HPLC Separations, Second Edition discusses the role of separation in high performance liquid chromatography (HPLC). This new and updated edition systematically presents basic concepts as well as new developments in HPLC. Starting with a description of basic concepts, it provides important guidance for the practical utilization of various HPLC procedures, such as the selection of the HPLC type, proper choice of the chromatographic column, selection of mobile phase and selection of the method of detection, all of which are in correlation with the physico-chemical characteristics of the compounds separated. Every chapter has been carefully reviewed, with several new sections added to bring the book completely up-to-date. Hence, it is a valuable reference for students and professors in chemistry. Provides a thoroughly updated resource, with an entirely new section on Computer-aided Method Development in HPLC and new subsections on miniaturization and automation in HPLC, chemometric aspects of HPLC, green solvent use in HPLC, and more Includes insights into the chromatographic process to find the optimum solution for analyzing complex samples Presents a basis for understanding the utilization of modern HPLC for applications, particularly for the analysis of pharmaceutical, biological, food, beverage and environmental samples

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:

Download or read book Synthesis and Characterization of C8 Bonded Stationary Phases for HPLC written by Xiaofang Pan and published by . This book was released on 2002 with total page 170 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 Synthesis and Characterization of Stationary Phases for Reversed phase Liquid Chromatography written by Dale Allen Shoemaker and published by . This book was released on 1992 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Synthesis and Characterization of Bent shaped Liquid Crystal written by Kala a/p Shanku Pillay and published by . This book was released on 2006 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of liquid crystal is relatively new area of chemistry, and therefore generates a large frontier of research. The ability of being able to produce high resolution display screens for use in televisions or laptop computers with a very low power consumption, has revolutionised the technological market for this product. As a result of the success of the knowledge already known about liquid crystals and their properties, and their as yet unexplored potential, it is not suprising that there is an extremely large amount of research into the area. In relation to this, in this project, a five ring bent-shaped liquid crystal, which is relatively new compound in liquid crystalline phase, was synthesized using several organic synthesis methods, such as, Diazonium coupling reaction, Williamson ether synthesis, hydrolysis and reaction with resorcinol. The compounds synthesized were characterized through FTIR analysis, melting point, and its physical apperances. Other than that, the percent yield for each compound also have been calculated. The compound synthesized in first step, ethyl4-4-(hydroxyphenylazo)benzoate was a red color solid with melting point at 235 C and the percent yield was 52.07%. In second step 3.542 grams of Ethyl-4-(4-hexadecanoxyphenylazo)benzoate which orange in color with melting point of 135 C was obtained. The percent yield from the reaction was 42.11%. The third compound synthesized was yellow color solid with melting point of 280-290 C and the final compound was 1,3-Phenelyne bis[4-(4-hexadecanoxyphenylazo)benzoate], a pale yellow color solid with melting point at range of 130-135 C was obtained.