PARTIAL SEPARATION ZONE TECHNIQUE FOR THE SEPARATION OF ENANTIOMERS BY AFFINITY ELECTROKINETIC CHROMATOGRAPHY WITH PROTEINS AS CHIRAL PSEUDO-STATIONARY PHASES

A previously reported technique which employed a discontinuous separation zone built in a part of a capillary was applied to the separation of enantiomers by affinity electrokinetic chromatography using proteins as chiral pseudo-stationary phases to avoid a detection problem caused by the presence of UV-absorbing materials in the separation solution. The technique was named ''partial separation zone technique'', where the capillary was partially filled with a solution containing a protein and the protein was not in the detector cell when analytes reached that cell. It was shown that the technique was successfully performed automatically using a commercial capillary electrophoresis instrument. The migration velocity of the protein was practically reduced to zero by using a coated capillary. The protein concentration could be increased in this technique to enhance resolution without the deterioration of the detector sensitivity. The detection sensitivity was remarkably improved using short-wavelength light in comparison with the conventional technique where the protein was added to the whole separation solution. The reproducibilities of the migration time and the peak area were evaluated, giving results comparable to those with the conventional method. Successful separations of basic racemates were achieved by the technique using bovine serum albumin, alpha(1)-acid glycoprotein, ovomucoid and conalbumin.