Separation of enantiomers on a chiral stationary phase based on pepsin .2. Stabilization by a mixed protein phase with chicken ovomucoid

A chiral stationary phase (CSP) based on a pepsin from porcine stomach mucosa and chicken ovomucoid (OMCHI) from egg whites has been prepared for the separation of basic and uncharged enantiomers. The Pepsin and OMCHI were mixed immobilized onto the same porous aminopropyl-silica materials using an N, N'-disuccinimidyl carbonate reaction. The retentive and enantioselective properties of the mixed protein phase (MPP), Pepsin-OMCHI CSP, were compared with those of a Pepsin CSP and an OMCHI stationary phase. The Pepsin-OMCHI CSP showed a similar enantioselectivity with the Pepsin CSP. In addition, the Pepsin-OMCHI CSP was more stable than the Pepsin CSP for repetitive injections of samples and the continuous flow of an eluent. The MPP was further stabilized by cross-linking with glutaraldehyde.