Peak parking determination of the obstruction factor in lauryl acrylate monolithic CEC columns

Abstract

The peak parking method was used to determine the obstruction factor of lauryl acrylate porous polymer monoliths. Polymers were prepared in situ in fused-silica capillaries using thermally initiated polymerization. These columns have been used for CEC of neutral analytes. Thiourea, which is unretained, was used as the test analyte for the obstruction factor measurement. The obstruction factor was determined to be 0.72 with a SD of (+/-0.01), which is consistent with the concept that organic porous polymer monoliths are more permeable than traditional LC stationary phases.

A thermodynamic study of capillary electrochromatographic retention of aromatic hydrocarbons on a lauryl acrylate porous polymer monolithic column with measured phase ratio

“…A few millimeters of the polyimide coating were removed from ends of the capillary by shaving with a razor. Column stability, reproducibility, and lifetimes have been previously reported [25–26].…”

“…Derivatized capillaries were immediately filled with polymer solution. This procedure has been described previously [1,[25][26].…”

“…A casting solvent was prepared by mixing 12.5 mg azobisisobutyronitrile as the free radical initiator, 12.5 mg 2-acrylamido-2-methylpropane sulfonic acid to support electroosmotic flow, 3.0 mL acetonitrile, 1.5 mL 1-propanol, and 0.5 mL of 5 mM pH 6.8 phosphate buffer. Our previous reports on thermodynamic studies for PPMs utilized mixtures of butyl and lauryl acrylates [1,[25][26][27]. Solubility issues limited the amount of lauryl acrylate that could be included.…”

Analytical chemistry research at primarily undergraduate institutions: training tomorrow's investigators

“…The result has been a prolic publication record covering both fundamentals and applications of multidimensional separations; Stoll has co-authored 10 peerreviewed research publications with 13 undergraduate coauthors since starting his faculty position in 2008. 40 Characterization of mobile phases, solvents, and buffer additives is also an active area of research. 33,34 Analytical chemists at other PUIs are actively developing new materials for chromatographic and electrophoretic methods.…”

“…39 Related research has characterized existing materials, for example, by applying the peak parking method to determine obstruction factors for polymer monoliths in capillary electrochromatography (CEC). 40 Characterization of mobile phases, solvents, and buffer additives is also an active area of research. Recent papers have investigated the effects of discontinuous buffer conditions on polyelectrolyte coatings for capillary electrophoresis 41 and used methyl-b-cyclodextran to enhance cholesterol coating of C18 stationary phases.…”