Separation of acidic and basic compounds in capillary electrochromatography with polymethacrylate-based monolithic columns.
Methacrylate-based monolithic columns with electroosmotic flow (EOF) or very weak EOF are prepared by in situ copolymerization in the presence of a porogen in fused-silica capillaries pretreated with a bifunctional reagent. Satisfactory separations of acidic and basic compounds on the column with EOF at either low or high pH are achieved, respectively. With sulfonic groups as dissociation functionalities, sufficient EOF mobility still remains as high as 1.74 x 10(-4) cm2 s(-1) V(-1) at low pH. Under this condition, seven acidic compounds are readily separated within 5.7 min. Moreover, at high pH, the peak shape of basic compounds is satisfactory without addition of any masking amines into running mobile phase since the secondary interaction between the basic compounds and the monolithic stationary phase are minimized at high pH. Reversed-phase mechanism for both acidic and basic compounds is observed under investigated separation conditions. In addition, possibilities of acidic and basic compound separations on a monolithic column with extremely low EOF are discussed.
Ping
Guichen
G
National Chromatographic Research and Analysis Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116011, China.
Zhang
Lihua
L
Zhang
Lin
L
Zhang
Weibing
W
Schmitt-Kopplin
Philippe
P
Kettrup
Antonius
A
Zhang
Yukui
Y
D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D011109:Polymethacrylic Acids / Q000737:chemistry*
D011109:Polymethacrylic Acids; C030613:polymethacrylic acid