Packed capillary columns chromatography

Contaminant by-products depend upon process routes to the product, so maximum impurity specifications may vary, eg, for CHA produced by aniline hydrogenation versus that made by cyclohexanol amination. Capillary column chromatography has improved resolution and quantitation of contaminants beyond the more fliUy described packed column methods (61) used historically to define specification standards. Wet chemical titrimetry for water by Kad Eisher or amine number by acid titration have changed Httle except for thein automation. Colorimetric methods remain based on APHA standards. 

Trisciani, A. and Andreolini, F, Evaluation of a micro-HPLC system dedicated to packed capillary column liquid chromatography, /. HRC CC, 13,270,1990. 

Applications High-temperature liquid chromatography with packed-capillary columns, nonaqueous mobile phases, and ELSD and ICP-MS detection, has been developed specifically as a robust analytical tool for the analysis of high-MW polymer additives [731,738]. Dissolving such moderately polar, heavy compounds with low water solubility at ambient temperature usually... 

MacNair, J.E., Lewis, K.C., Jorgenson, J.W. (1997). Ultrahigh-pressure reversed-phase liquid chromatography in packed capillary columns. Anal. Chem. 69, 983-989. 

Rruss, A., Kempter, C., Gysler, 1., and lira, T., Evaluation of packed capillary liquid chromatography columns and comparison with conventional-size columns. Journal of Chromatography A 1030(1-2), 167-176, 2004. 

Shen, Y., Lee, M.L. (1997) High-speed gas chromatography using packed capillary columns. 1. Microcolvunn Sep. 9 21-27. 

FLOW. The rate at which zones migrate down the column is dependent upon equilibrium conditions and mobile phase velocity on the other hand, how the zone broadens depends upon flow conditions in the column, longitudinal diffusion, and the rate of mass transfer. Since there are various types of columns used in gas chromatography, namely, open tubular columns, support coated open tubular columns, packed capillary columns, and analytical packed columns, we should look at the conditions of flow in a gas chromatographic column. Our discussion of flow will be restricted to Newtonian fluids, that is, those in which the viscosity remains constant at a given temperature. 

J. Cai and J. Henion, Quantitative multi-residue determination of /3-agonists in bovine urine using on-line immunoaffinity extraction-coupled column packed capillary liquid chromatography-tandem mass spectrometry , 7. Chromatogr. 691 357-370 (1997). 

Kennedy, R. T. Jorgenson, J. W. 1989. Preparation and evaluation of packed capillary liquid chromatography columns with inner diameters from 20 to 50pm. Anal. Chem., 61,1128-1135. 

Polak and Molenaar described a method for the determination of acetylcholine from brain tissue by pyrolysis-gas chromatography-mass spectrometry [200]. The deuterium-labeled acetyl-choline is pyrolytically demethylated with sodium benzenethiolate, followed by quantitative GC-MS analysis. In this method, care must be taken so that the samples do not contain appreciable amounts of choline since exchange of deuterium-labeled groups between acetylcholine and choline during pyrolysis may yield erroneous results. The same authors have also reported a method for the determination of acetylcholine by slow pyrolysis combined with mass fragment analysis on a packed capillary column [201]. 

Gas chromatography may be divided into gas solid chromatography (mainly adsorptive processes) and gas-liquid chromatography (mainly partition) depending on whether the stationary phase is a solid or a liquid at its operating temperature. If the stationary phase is a hquid it must be coated on a support for packed coliunn chromatography. For capillary column chromatography, the stationary phase may be coated directly on to the walls of the coliunn, or on to a support which is bonded to the... 

FIGURE 4.6 Capillary liquid chromatography electrospray ionization mass spectrometry (cap-LC-ESI-MS) used to concentrate, separate, and analyze low amounts (fmoles) of peptides or proteins. The packed capillary column length is typically 10 cm long and the column flow rate is maintained at 100 to 1000 nL/min. The inset shows the electrospray tip formed at the end of a 100-pm i.d. fused silica capillary column. 

Ibanez, E., Lopez-Sebastian, S., Tabera, J., and Reglero, G. 1998. Separation of carotenoids by subcritical fluid chromatography with coated, packed capillary columns and neat carbon dioxide. 

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