Systematic liquid chromatography

Figure 5.1 Pesticides included in the systematic investigations on APCI-MS signal response dependence on eluent flow rate the parameter IsTow represents the distribution coefficient of the pesticide between n-octanol and water. Reprinted from J. Chromatogr, A, 937, Asperger, A., Efer, 1., Koal, T. and Engewald, W., On the signal response of various pesticides in electrospray and atmospheric pressure chemical ionization depending on the flow rate of eluent applied in liquid chromatography-mass spectrometry , 65-72, Copyright (2001), with permission from Elsevier Science.

Baczek, T., Markuszewski, M., Kaliszan, R. Linear and quadratic relationships between retention and organic modifier content in eluent in reversed phase high-performance liquid chromatography a systematic comparative statistical study. 

Several improved stationary phase materials have been synthesized for reversed-phase liquid chromatography. One material is vinyl alcohol copolymer gel. This stationary phase is quite polar and chemically very stable however, it demonstrated a strong retention capacity for polycyclic aromatic hydrocarbons.45 9 Although stable octadecyl- and octyl-bonded silica gels have been synthesized from pure silica gel50,51 and are now commercially available, such an optimization system has not yet been built. Further experiments are required to elucidate the retention mechanism, and to systematize it within the context of instrumentation. 

Muller, C., Schafer, P., Stortzel, M., Vogt, S., and Weinmann, W. (2002). Ion suppression effects in liquid chromatography-electrospray-ionization transport-region collision induced dissociation mass spectrometry with different serum extraction methods for systematic toxicological analysis with mass spectra libraries. /. Chromatogr. B 773, 47— 52. 

K. J. Veals, J. Hsieh, Y. etal. Cassette-accelerated rapid rat screen a systematic procedure for the dosing and liquid chromatography/ atmospheric pressure ionization tandem mass spectrometric analysis of new chemical entities as part of new drug discovery. Rapid Commun Mass Spectrom 2001, 15, 335-340. 

SG Penn, G Liu, ET Bergstrom, DM Goodall, JS Loran. Systematic approach to treatment of enantiomeric separations in capillary electrophoresis and liquid chromatography. I. Initial evaluation using propranolol and dansylated amino acids. J Chromatogr A 680 147-155, 1994. 

There have been several reports of the separation of a- and / -pyranose forms during liquid chromatography of sugars.46-49 Initially, this was regarded as a nuisance, but systematic attempts were later made to improve this separation. At 0°, with 1 4 water-acetonitrile as the eluant, many aldoses were separated into two components.48 Galactose and al-trose showed small peaks probably representing the furanose forms ... 

The book provides systematic and detailed descriptions of the numerous approaches to chiral resolution. The first chapter is an introduction to basic concepts of molecular chirality and liquid chromatography. Chapters 2 through 9 discuss the chiral resolution of various classes of chiral stationary phases. Chapter 10 deals with chiral resolution using chiral mobile phase additives. These discussions elaborate the types, structures, and properties of the chiral phases,... 

In addition to their application to liquid chromatography, macrocycles have been applied to gas chromatographic separations as well. Kartsova et al. [20] performed a systematic study of a series of crown ethers and cryptands adsorbed onto GC stationary phases. The influence on the polarity and selectivity of the stationary phases of the type and number of heteroatoms, conformational lability of the cavity, the presence of substituents, and the concentration of macrocycle was studied with respect to the separations of various classes of organic compounds. Phases containing mixtures of two macrocycles were found to be most promising. 

Maurer, H. H. Kraemer, T. Ledvinka, O. Schmitt, C. J. Weber, A. A. 1997. Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in toxicological analysis. Studies on the detection of clobenzorex and its metabolites within a systematic toxicological analysis procedure by GC-MS and by immunoassay and studies on the detection of alpha- and beta-amanitin in urine by atmospheric pressure ionization electrospray LC-MS. J. Chromatogr. B Biomed. Sci Appl., 689,81-89. 

R. A. de Zeeuw, J. P. Franke, and M. Bogusz, High performance liquid chromatography with a multichannel diode-array spectro-photometric detector in systematic toxicological analysis. In Analytical Methods in Forensic Chemistry (M. H. Ho, ed.), Ellis Horwood, New York, 1990, p. 212. 

Remane D, Meyer MR, Wissenbach DK, Maurer HH (2010) Ion suppression and enhancement effects of co-eluting analytes in multi-analyte approaches systematic investigation using ultra-high-performance liquid chromatography/mass spectrometry with atmospheric-pressure chemical ionization or electrospray ionization. Rapid Commun Mass Spectrom 24(21) 3103— 3108. doi 10.1002/rcm.4736... 

Tso J, Aga DS (2010) A systematic investigation to optimize simultaneous extraction and liquid chromatography tandem mass spectrometry analysis of estrogens and their conjugated metabolites in milk. J Chromatogr A 1217 4784-4795... 

Thin layer chromatography and gas-liquid chromatography have been widely applied for the separation and for the identification of thiazoles in reaction mixtures. From systematic studies it appears that thiazole, alkyl- and aryl-thiazoles and benzothiazoles are best separated on stationary phase of low polarity in GLC and with eluents of low polarity in TLC. It has been possible to correlate, for these series of compounds, the RF of TLC or the specific volume of retention in GLC with the number of carbon atoms in the aliphatic side chain, and also with the rate constants of quaternization of the cyclic nitrogen atom. This last observation indicates a significant participation of the nitrogen atom in the chromatographic processes (67BSF846). 

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