Investigation of the novel mixed-mode stationary phase for capillary electrochromatography. II. Separation of amino acids and peptides on sulfonated naphthalimido-modified silyl silica gel.
The potential of 3-(4-sulfo-1,8-naphthalimido)propyl-modified silyl silica gel (SNAIP) as a mixed-mode stationary phase for capillary electrochromatography (CEC) was investigated for the separation of charged analytes, taking four amino acids (tyrosine, phenylalanine, tryptophan, histidine) as model analytes. The elution process of these charged analytes in CEC with SNAIP was dominated by a combination of both electrophoretic process and chromatographic process involving hydrophobic as well as electrostatic interactions. In order to study the retention mechanism, the CEC retention factor k* and the velocity factor ke* were measured for the amino acids, which allowed the assessment of the respective contribution from the differential processes underlying the separation. Migration and retention could be mediated by changing various mobile phase compositions, including buffer pH, buffer concentration, and concentration of organic solvent. Based on the results obtained by separation of the amino acids, the separation of eight peptides (Gly-Val, Gly-Phe, Gly-Ile, Gly-His, Gly-Lys, Lys-Lys, Gly-Gly-Gly, Gly-Gly-His) was attempted. A good separation was achieved under an isocratic elution with a mobile phase consisting of 35 mM phosphate buffer (pH 3.8) and 40% methanol.
Graduate School of Biomedical Sciences, Course of Pharmaceutical Sciences, Nagasaki University, Nagasaki, Japan.
Kaname
K
Ohyama
Yumi
Y
Shirasawa
Mitsuhiro
M
Wada
Naoya
N
Kishikawa
Yoshihito
Y
Ohba
Kenichiro
K
Nakashima
Naotaka
N
Kuroda
D000596:Amino Acids / Q000302:isolation & purification*; D002021:Buffers; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D000432:Methanol / Q000737:chemistry; D009282:Naphthalenesulfonates / Q000737:chemistry*; D010455:Peptides / Q000302:isolation & purification*; D058428:Silica Gel; D012822:Silicon Dioxide / Q000737:chemistry*
D000596:Amino Acids; D002021:Buffers; D009282:Naphthalenesulfonates; D010455:Peptides; D058428:Silica Gel; D012822:Silicon Dioxide; D000432:Methanol