Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Open tube capillary

The performance of the monolithic silica in a capillary seems to be dominated by the size of the large through-pores and slow EOF. In the van Deemter plot for open-tube capillary chromatography, a plate height (H) partly depends on the square of dc as in Eqn. 5.4 (Ds, diffusion coefficient in the stationary phase dc, inner diameter of the capillary df, thickness of the stationary layer) [30], This also explains the reduction in the number of theoretical plates with a solute having the longer retention. [Pg.188]

As previously mentioned, electrophoretic separations using open-tube capillaries are based on solute differential mobility, which is a function of charge and molecular size. A different approach is required for separating neutral or uncharged compounds. Because charge is absent, electrophoretic mobility is zero. Electro-osmotic flow would allow them to migrate, but their velocities would be equal. Separation would not be possible with the above method. [Pg.602]

Capillary electrophoresis (CE) is a powerful separation technique. It is especially useful for separation of ionic compounds and chiral mixtures. Mass spectrometry has been coupled with CE to provide a powerful platform for separation and detection of complex mixtures such as combinatorial libraries. However, the full potential of CE in the application of routine analysis of samples has yet to be realized. This is in part due to perceived difficulty in the use of the CE technique compared to the more mature techniques of HPLC and even SFC. Dunayevskiy et al. [136] analyzed a library of 171 theoretically disubstituted xanthene derivatives with a CE/ESI-MS system. The method allowed the purity and makeup of the library to be determined 160 of the expected compounds were found to be present, and 12 side products were also detected in the mixture. Due to the ability of CE to separate analytes on the basis of charge, most of the xanthene derivatives could be resolved by simple CE-MS procedures even though 124 of the 171 theoretical compounds were isobaric with at least one other molecule in the mixture. Any remaining unresolved peaks were resolved by MS/MS experiments. The method shows promise for the analysis of small combinatorial libraries with fewer than 1000 components. Boutin et al. [137] used CE-MS along with NMR and MS/MS to characterize combinatorial peptide libraries that contain 3 variable positions. The CE-MS method was used to provide a rapid and routine method for initial assessment of the construction of the library. Simms et al. [138] developed a micellar electrokinetic chromatography method for the analysis of combinatorial libraries with an open-tube capillary and UV detection. The quick analysis time of the method made it suitable for the analysis of combinatorial library samples. CE-MS was also used in the analysis... [Pg.211]

OCEC Open (tube) Capillary Electro Chromatography... [Pg.161]

Figure 8.2. MEKC separation of some corticosteroids using (A) 50-mM SDS and (B) 50-mM sodium cholate as the surfactant in the run buffer. The solution also contained 25-mM sodium borate pH 9.0. The separation was performed with a 57-cm open tube capillary. The compounds were detected at 200mn. Figure 8.2. MEKC separation of some corticosteroids using (A) 50-mM SDS and (B) 50-mM sodium cholate as the surfactant in the run buffer. The solution also contained 25-mM sodium borate pH 9.0. The separation was performed with a 57-cm open tube capillary. The compounds were detected at 200mn.
Figure 8.4. Electropherogram of some corticosteroids using a run buffer composed of ( 4) 25-mM sodium borate pH 9.0,50-mM sodium deoxycholate, 5% acetonitrile, and (B) 25-mM sodium borate pH 9.0,50-mM sodium deoxycholate, 10% acetonitrile. The capillary used was a 57-cm open tube capillary, and the compounds were detected with UV detection at 2.00 nm. Figure 8.4. Electropherogram of some corticosteroids using a run buffer composed of ( 4) 25-mM sodium borate pH 9.0,50-mM sodium deoxycholate, 5% acetonitrile, and (B) 25-mM sodium borate pH 9.0,50-mM sodium deoxycholate, 10% acetonitrile. The capillary used was a 57-cm open tube capillary, and the compounds were detected with UV detection at 2.00 nm.
Figure 8. Electropherograms of (.A) 1st injection and (B) 60th injection of the (1) hydrocortisone 21-hemisuccinate, (2) hydrocortisone, (3) hydrocortisone 21-cypionate, and (4) impurity using a 27 cm X 50pm open tube capillary with 10-mM sodium tetraborate, 100-mM SDS, and 50-mM hydroxypropyl-p-cyclodextrin. Figure 8. Electropherograms of (.A) 1st injection and (B) 60th injection of the (1) hydrocortisone 21-hemisuccinate, (2) hydrocortisone, (3) hydrocortisone 21-cypionate, and (4) impurity using a 27 cm X 50pm open tube capillary with 10-mM sodium tetraborate, 100-mM SDS, and 50-mM hydroxypropyl-p-cyclodextrin.
Figure 8.11. Electropherograms of compounds generated from four 400 compound libraries using a 27cm X 50pm open tube capillary with a 100-mM SDS, 50-mM hydroxypropyl-P-cyclodextrin, 10-mM sodium tetraborate run buffer. UV detection at 254nm. The electropherograms show the different levels of purity of each sample and resolution that ean be obtained in a short period of time. Figure 8.11. Electropherograms of compounds generated from four 400 compound libraries using a 27cm X 50pm open tube capillary with a 100-mM SDS, 50-mM hydroxypropyl-P-cyclodextrin, 10-mM sodium tetraborate run buffer. UV detection at 254nm. The electropherograms show the different levels of purity of each sample and resolution that ean be obtained in a short period of time.
Schweitz, L. Molecularly imprinted polymer coatings for open-tube capillary electrochromatography prepared by surface initiation. Anal. Chem. 2002, 74, 1192-1196. [Pg.489]

Most GC analyses, and almost all that are concerned with trace quantitative analysis, are nowadays conducted using unpacked (open tube) capillary columns the following discussion will be mainly concerned with these. In this regard, a great deal is owed to Golay (see the accompanying textbox), who was responsible for both the underlying theory and the first practical demonstrations. [Pg.147]

German, A. L., and Homing, E. C. Thermostable Open Tube Capillary... [Pg.90]


See other pages where Open tube capillary is mentioned: [Pg.74]    [Pg.250]    [Pg.259]    [Pg.21]    [Pg.623]    [Pg.1659]    [Pg.619]    [Pg.200]    [Pg.200]    [Pg.201]    [Pg.150]    [Pg.142]   
See also in sourсe #XX -- [ Pg.1659 ]




SEARCH



Capillary tubes

Open Tube

Open-tube capillary electrophoresis

© 2024 chempedia.info