Molecular composition zone electrophoresis

Capillary zone electrophoresis (CZE), micellar capillary electrokinetic chromatography (MECC), capillary gel electrophoresis (CGE), and affinity capillary electrophoresis (ACE) are CE modes using continuous electrolyte solution systems. In CZE, the velocity of migration is proportional to the electrophoretic mobilities of the analytes, which depends on their effective charge-to-hydrodynamic radius ratios. CZE appears to be the simplest and, probably, the most commonly employed mode of CE for the separation of amino acids, peptides, and proteins. Nevertheless, the molecular complexity of peptides and proteins and the multifunctional character of amino acids require particular attention in selecting the capillary tube and the composition of the electrolyte solution employed for the separations of these analytes by CZE. 

Carbohydrate analysis using enzymatic hydrolysis and subsequent capillary zone electrophoresis (ENZ/CZE) revealed the number of 4-0-methylglucuronic acid units to be approximately one unit per nineD-xylose residues (Table 4). No glucuronic acid units were detected. The carbohydrate composition of the polysaccharide isolated here from aspen wood is quite similar to that previously reported for typical hardwood xylans . SEC analysis indicated the molecular weight (Mw) to be 15000 g/mol. 

It is a remarkable and indeed essential feature of the method that boundary anomalies which may seriously interfere in boundary electrophoresis appear to influence zone electrophoresis to a much smaller degree. A detailed investigation of this in zone electrophoresis has not yet been made, but it appears likely that two factors are of importance in this respect. First the concentration of the migrating substance in each zone is generally lower than in boundary experiments. Second, as the front and the rear of each zone are much closer than in U-tube experiments, diffusion of electrolytes may tend to even out to some degree the local differences in the composition of the medium which are the cause of these anomalies. In any case, as has already been mentioned, zone electrophoresis is applicable to a number of substances of comparatively low molecular weight which are difficult or impossible to study in boundary electrophoresis because of pronounced boundary anomalies (e.g., amino acids, peptides, and nucleotides). 

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