Cationic starch derivatives as dynamic coating additives for protein analysis in capillary electrophoresis.
Positively charged starch derivatives were used to modify the inner surface of fused-silica capillaries by addition to running buffer, which were subsequently employed in capillary electrophoresis (CE). Capillaries coated with the cationic starch derivatives were shown to generate a stable, reversed electroosmotic flow (EOF) in the investigated pH range of 3-9. The presented coating procedure was fast, based on a simple rinsing protocol where the polymer created a physically adsorbed, cationic polymer layer. Among the additives studied, a quaternary ammonium starch derivative showed a fast EOF mobility and effectively suppressed the adsorption of proteins. The intra- and inter-day reproducibility of the coating referring to the EOF mobility were satisfactory with relative standard deviation (RSD) of 0.27 and 1.67%, respectively. The coating enabled separation of some protein mixtures including basic proteins within l3 min with efficiencies up to 280,000 plates/m. In addition, this cationic starch derivative possessed a good solubility (about 100mg/mL), and it does not significantly contribute to the background adsorption in the UV region of 190-400 nm.
Sakai-Kato
Kumiko
K
Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan. kumikato@musashino-u.ac.jp
Kato
Masaru
M
Nakajima
Tohru
T
Toyo'oka
Toshimasa
T
Imai
Kazuhiro
K
Utsunomiya-Tate
Naoko
N
D002412:Cations; D019075:Electrophoresis, Capillary / Q000379:methods*; D011506:Proteins / Q000032:analysis*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013213:Starch / Q000737:chemistry*
D002412:Cations; D011506:Proteins; D013213:Starch