title: Control of electroosmotic flow by a cation additive to enhance the separation of amino acids by micellar electrokinetic chromatography.
abstract: The effect of a divalent cation (Mg2+) and 3 monovalent cations (Na+, Li+, and K+) as buffer additives on the electroosmotic flow (EOF) was investigated in order to improve the separation performance of p-acetamidobenzenesulfonyl fluoride (PAABS-F) derivatives of 20 standard amino acids by micellar electrokinetic chromatography (MEKC). The EOF can be decreased with increasing concentration of cations with the order of cations as Mg2+>K+>Na+>Li+. However, it was found that the resolution cannot be improved easily using a buffer cation which is more capable of decreasing the EOF. Taking the migration time, resolution, and peak shape into account, Na+ is the best buffer additive, although the EOF decreased most using Mg2+. Using 20 mmol/L borate at pH 9.3 containing 140 mmol/L SDS and 20 mmol/L Na+ as electrolyte, 20 standard amino acids were successfully separated within 14 min.
authors.affiliation: Jiangsu Key Laboratory of Environmental Materials and Environmental Engineering, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China. quqishu@gmail.com
authors.forename: Qishu
authors.initials: Q
authors.lastname: Qu
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Tang
authors.forename: Debby
authors.initials: D
authors.lastname: Mangelings
authors.forename: Chengyin
authors.initials: C
authors.lastname: Wang
authors.forename: Gongjun
authors.initials: G
authors.lastname: Yang
authors.forename: Xiaoya
authors.initials: X
authors.lastname: Hu
authors.forename: Chao
authors.initials: C
authors.lastname: Yan
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D002412:Cations / Q000737:chemistry*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D000596:Amino Acids; D002412:Cations