title: Use of quasi-isoelectric buffers to limit protein adsorption in capillary zone electrophoresis.
abstract: The use of quasi-isoelectric buffers consisting of narrow pH cuts of carrier ampholytes (NC) has been investigated to limit protein adsorption on capillary walls during capillary zone electrophoresis experiments. To quantify protein adsorption on the silica surface, a method derived from that of Towns and Regnier has been developed. alpha-Lactalbumin (14 kDa, pI 4.8) and alpha-chymotrypsinogen A (25 kDa, pI 9.2) have been used as model proteins. Acidic narrow pH cuts of carrier ampholytes (NC, pH 3.0) obtained from fractionation of Serva 4-9 carrier ampholytes were used as BGE in bare-silica capillaries, and allowed to decrease significantly protein adsorption, as compared to experiments performed with classical formate buffer. The use of NC as BGE appeared to be as efficient as the use of polydimethylacrylamide coating to prevent protein adsorption. This increase of protein recovery when using NC was attributed to the interaction of carrier ampholytes with the silica surface, leading to a shielding of the capillary wall.
authors.affiliation: Laboratoire Environnement et Chimie Analytique, UMR CNRS 7121, ESPCI, Paris, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Poitevin
authors.forename: Karim
authors.initials: K
authors.lastname: Hammad
authors.forename: Ichraf
authors.initials: I
authors.lastname: Ayed
authors.forename: Pier Giorgio
authors.initials: PG
authors.lastname: Righetti
authors.forename: Gabriel
authors.initials: G
authors.lastname: Peltre
authors.forename: Stephanie
authors.initials: S
authors.lastname: Descroix
mesh_terms: D000178:Acrylamides; D000327:Adsorption; D000665:Ampholyte Mixtures; D000818:Animals; D002021:Buffers; D002919:Chymotrypsinogen / Q000032:analysis / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D007526:Isoelectric Point; D007768:Lactalbumin / Q000032:analysis / Q000737:chemistry; D011506:Proteins / Q000032:analysis / Q000737:chemistry*; D012822:Silicon Dioxide
chemical_list: D000178:Acrylamides; D000665:Ampholyte Mixtures; D002021:Buffers; D011506:Proteins; C429790:poly(N,N-dimethylacrylamide); D012822:Silicon Dioxide; D007768:Lactalbumin; D002919:Chymotrypsinogen