Free solution capillary

P. D. Grossman, J. C. Colburn, H. H. Lauer, R. G. Nielsen, R. M. Riggin, G. S. Sittampalam and E. C. Rickard, Application of free-solution capillary electrophoresis to the analytical scale separation of proteins and peptides . Anal. Chem. 61 1186-1194 (1989). 

Bullock, J.A. and Yuan, L.-C., Free solution capillary electrophoresis of basic proteins in uncoated fused silica capillary tubing, ]. Microcol. Sep., 3,241,1991. 

Tran, A. D., Park, S., Lisi, P. J., Huynh, O. T., Ryall, R. R., and Lane, P. A., Separation of carbohydrate-mediated microheterogeneity of recombinant human erythropoietin by free solution capillary electrophoresis. Effects of pH, buffer type and organic additives,. Ckromatogr., 542, 459, 1991. 

Lee, K.-J. and Heo, G. S., Free solution capillary electrophoresis of proteins using untreated fused-silica capillaries, ]. Chromatogr., 559, 317, 1991. 

FSCE Free solution capillary detector (see ELCD)... 

VJ Hilser, CD Worosila, E Freire. Analysis of thermal-induced proteins folding/ unfolding transitions using free-solution capillary electrophoresis. Anal. Biochem. 208 125-131 (1993). 

DK Lloyd, S Li, P Ryan. Protein chiral selectors in free-solution capillary electrophoresis and packed-capillary electrochromatography. J Chromatogr A 694 285-296, 1995. 

Hall et al. (127) compared free solution capillary electrophoresis (FSCE) and micellar elec-trokinetic capillary chromatography (MEKC) techniques with HPLC analysis. Four major food-grade antioxidants, propyl gallate (PG), BHA, BHT, and TBHQ, were separated. Resolution of the 4 antioxidants was not successful with FSCE, but was with MEKC. Separation was completed with excellent resolution and efficiency within 6 min and picomole amounts of the antioxidants were detectable using UV absorption. In contrast, reversed-phase HPLC separation was not as efficient and required larger sample amounts and longer separation time. 

Jorgenson and Lukacs [8] have described a number of parameters, which may be helpful in characterizing CE separations. The linear velocity (v) of a given analyte in free-solution capillary electrophoresis may be represented by the following equation ... 

The key operational parameter in free-solution capillary electrophoresis is the pH of the running buffer, as the electroosmotic flow and ionization of the analyte can be regulated by this variable. The role of buffers in capillary electrophoresis has been discussed in detail, with emphasis on buffer concentration, buffer type, and pH effects [10]. The effect of organic solvents on separation and migration behavior has been studied for dipeptides [11] and somatostatin analog peptides [12]. The order of migration as well as the selectivity may be manipulated by organic modifiers in... 

Figure 17 shows the autoradiographic detection of the 3P-labeled polydeoxyadenosine homopolymer sample, which is the same sample as shown in Figures 15 and 16. The gain in sensitivity is several orders of magnitude. Indeed, it is even possible to discern S3P-labeled material "trapped" in the gel matrix between peaks. Clearly this method is the method of choice when sensitivity is an issue. The same method can also be applied to free-solution capillary electrophoresis. 

Other methodologies. Desportes et al. (2000) isolated several small wine peptides (Mr <3000) using RP-HPLC on a porous graphite carbon Hypercarb column. The purity of the fractions collected was confirmed by free-solution capillary electrophoresis (FSCE). In a later study, Desportes et al. (2001) determined the peptide sequence of some isolated peptides by Edman degradation. 

Bishop, R.T., Turula, V.E., and de Haseth, J.A. Study of Conformational Effects on Reversed-Phase Chromatography of Proteins with Particle Beam LC/FT-IR Spectrometry and Free Solution Capillary Electrophoresis (1996) Anal. Chem., in press. 

CZE, also referred to as free solution capillary electrophoresis (FSCE), or open tubular capillary electrophoresis (OT CE), is the format originally described, in which the capillary is filled with an electrolyte buffer solution. In CZE, molecules are separated directly according to their charge, and inversely according to their solution drag force. Neutral molecules are moved through the capillary by the EOF. There are many additives which can be used to either dynamically deactivate the fused capillary waU, and prevent undesirable solute sticking, or to enhance solute selectivity, or both. 

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