ABSTRACT
A fast method for the generation of permanent hydrophilic capillary coatings for capillary electrophoresis (CE) is presented. Such interior coating is effected by treating the surface to be coated with a solution of glutaraldehyde as cross-linking agent followed by a solution of poly(vinyl alcohol) (PVA), which results in an immobilization of the polymer on the capillary surface. Applied for capillary zone electrophoresis (CZE) such capillaries coated with cross-linked PVA exhibit excellent separation performance of adsorptive analytes like basic proteins due to the reduction of analyte-wall interactions. The long-term stability of cross-linked PVA coatings could be proved in very long series of CZE separations. More than 1000 repetitive CE separations of basic proteins were performed with stable absolute migration times relative standard deviation (RSD > 1.2%) and without loss of separation efficiency. Cross-linked PVA coatings exhibit a suppressed electroosmotic flow and excellent stability over a wide pH range.
Subject(s)
Electrophoresis, Capillary/methods , Polyvinyl Alcohol , Chymotrypsinogen/isolation & purification , Coated Materials, Biocompatible , Cross-Linking Reagents , Cytochromes/isolation & purification , Drug Stability , Electrophoresis, Capillary/instrumentation , Glutaral , Hydrogen-Ion Concentration , Indicators and Reagents , Muramidase/isolation & purification , Reproducibility of Results , Trypsinogen/isolation & purificationABSTRACT
The combination of liquid chromatography (HPLC), UV/Vis-spectroscopy and circular dichroism (CD) can be used to construct a high-throughput screening system to determine the enantioselectivity of enzyme- or metal-catalyzed reduction of acetophenone with formation of (S)- and (R)-1-phenylethanol. Prerequisite for the viability of this system is the experimental finding that the anisotropy factor g is linearly related to the enantiomeric excess (ee) and that it is independent of concentration, thereby excluding possible aggregation effects.
