Chromatography capillary columns

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. 

Heart-cutting, with trapping and re-injection, using isothermal dual capillary column chromatography for separation of the UV photolysis products of methyl... 

Bamba, T., Fukusaki, E., Minakuchi, H., Nakazawa, Y, and Kobayashi, A., Separation of polyprenol and dolichol by monolithic silica capillary column chromatography. Journal of Lipid Research 46(10), 2295-2298, 2005. 

The recorder is a dynamic device its pen must move as a function of a signal that is changing with time. The dynamic properties of the pen, then, can become critical when the signal changes very rapidly as it does, for example in capillary column chromatography. Recorder response affects the fidelity of the plot. Since the recorder cannot respond any faster than its de-... 

Figure 12.13 Illustration of isothermal dual capillary column chromatography used for separation of UV photolysis products of methyl isopropyl ether, (a) Heart-cut and back-flushing at preseparation chromatogram 1, PPG pre-column (20 m X 0.25 mm i.d.) 55 °C, 0.2 bar N2 3jxL. Chromatogram 2, Marlophen main column (100 m X 0.25 mm i.d.) 1.5 bar N2 sample, heart-cut from chromatogram 1. (b) Obtained under the same conditions as (a), but without trapping of the heart-cut. Reprinted with permission from Ref. (19).

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... 

All petroleum-derived waxes, including blends of waxes, from n-Cn to n-C44 can be separated by capillary column chromatography (ASTM D-5442). In this method, the sample is diluted in a suitable solvent with an internal standard, after which it is injected into a capillary column meeting a specified resolution, and the components are detected with a flame ionization detector. The eluted components are identified by comparison with a standard mixture, and the area of each straight-chain and branched-chain alkane is measured. 

Thin peaks, which can arise frequently with capillary column chromatography, are easy to evaluate. 

Figure 6. Effect of the extent of cracking (condensed-oil basis) on three 1-alkene/ n-alkane ratios. The ratios were determined by capillary column chromatography with an FID detector. C8 ) C12 (O) C18 ([J).

Burnham, A. K. Clarkson, J. E. "Determination of Process Yield for OiT Shale Retorting Using Oil Analysis by Capillary Column Chromatography," Proc. 13th Oil Shale Symp., J. H. Gary, Ed. Colorado School of Mines Press Golden, CO, 1980 p. 269. 

Liao, J. L., Continuous bed for conventional column and capillary column chromatography, Adv. Chromatogr., 40, 467, 2000. 

Microbore columns (0.8 to 1 nun i.d.) offer a compromise between wide-bore and capillary columns. Chromatography separation with these colunms is carried out at flow rates of 20 to 100 p,Lmin HPLC hardware is available that can deliver a precise volume and solvent composition in this low flow range. These... 

The most important detector in capillary column chromatography is the mass spectrometer. Experience has shown that any chromatographic method that cannot be coupled with a mass spectrometer remains of little practical relevance in the long term. In this context, it must be taken into consideration that high-temperature GC-MS was developed during a transitional phase, at a time when HPLC-MS was... 

Barnung, T.N. and Grahl-Nielsen, O. Determination of benzenes and naphthalenes in water by purge and trap isolation and capillary column chromatography. Journal of Chromatography 1989, 466, 271-278. 

R-13 Tsuge S. Characterization of polymers by high-resolution pyrolysis-gas chromatography with fiised-silica capillary columns. Chromatography Forum 1986 1 44-51. 

The separation of waxes on packed columns has been carried out since the 1960s [2,3 ], and capillary column chromatography was used in 1970 to separate a microcrystalline wax up to carbon chain length (also known as carbon number) M Csg [4]. In the early 1980s, tire manufacturers requested ASTM D02.04 to produce a capillary column gas chromatography method to analyze rubber waxes (with oil content of less than 10%) from carbon number -C,7 to n-C44. ASTM D02.10, the Subcommittee on Petroleum Wax, was asked by D02.04 to carry out the development of the method. 

Gas Chromatograph (GC) (for a Fused Silica Column)—k multi-ramp temperature, programmable GC built for capillary column chromatography. It must have a flame ionization detector and a split injection system that will not discriminate over the boiling range of the samples analyzed. 

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