Evaluation of poly{-N-isopropylacrylamide-co-[3-(methacryloylamino)propyl]trimethylammonium} as a stationary phase for capillary electrochromatography.
A cationic polyacrylamide-based stationary phase was synthesized and characterized for CEC. The stationary phase was prepared by radical copolymerization of N-isopropylacrylamide (NIPAAm) and (3-(methacryloylamino)propyl)trimethylammonium chloride (MAPTA), producing a copolymer attached to 5 microm porous silica particles. Fourier transform infrared spectroscopy and thermogravimetric analysis were used to characterize the copolymer. Under capillary electrochromatographic conditions, the poly-NIPAAm-co-MAPTA stationary phase showed to be stable in a wide pH range. The amino groups in the MAPTA provided an anodic EOF for CEC separation. The electroosmotic mobility changed less than 10% when the pH of the mobile phase was changed from 2 to 12. The run-to-run RSD of analyte migration time was less than 1.5% (n = 3), and the RSD of peak area was less than 3% (n = 3). The day-to-day RSD for migration time was less than 2% (n = 3). The polar groups present in the stationary phase contributed to the selectivity of the phase providing for hydrophilic interactions. In the separation of a series of neutral and acidic compounds, the stationary phase shows a mixed-mode separation mechanism with both hydrophobicity and hydrophilicity contributing to the separation.
Zhang
Xin
X
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
Colón
Luis A
LA
D000178:Acrylamides; D000643:Ammonium Chloride; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates; D009995:Osmosis; D011108:Polymers; D012822:Silicon Dioxide; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
D000178:Acrylamides; D008689:Methacrylates; D011108:Polymers; D000643:Ammonium Chloride; D012822:Silicon Dioxide; C400723:MAPTAC