Cereal Chem. 73 (1):81-87 | VIEW ARTICLE
Analytical Techniques and Instrumentation
Improvements in Cereal Protein Separations by Capillary Electrophoresis: Resolution and Reproducibility (1).
George L. Lookhart (2) and Scott R. Bean (3). (1) Cooperative investigations, U.S. Department of Agriculture, Agricultural Research Service and the Department of Grain Science and Industry, Kansas State University. Contribution 95-534-J, Department of Grain Science and Industry, Kansas State Agricultural Experiment Station, Manhattan, KS 66506. Mention of firm names or trade products does not constitute endorsement by the U.S. Department of Agriculture over others not mentioned. (2) Research Chemist, USDA-ARS, Grain Marketing Research Laboratory, Manhattan, KS 66502. Fax 913/776-2792. (3) Research Assistant, Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506. U.S. Department of Agriculture, Agricultural Research Service, Northern Plains Area, is an equal opportunity/affirmative action employer and all agency services are available without discrimination. Accepted September 2, 1995. Copyright 1996 by the American Association of Cereal Chemists, Inc.
Capillary electrophoresis rinsing protocols and buffer compositions were optimized to improve the resolution and reproducibility of cereal prolamin separations. Capillary cleaning protocols were varied to improve reproducibility. Four cleaning regimes were tested; the optimum was a 4-min rinse with 1M phosphoric acid. Several buffer modifiers were tested for use with 100 mM phosphate buffer (pH 2.5) containing 0.05% hydroxypropylmethylcellulose. Twenty percent acetonitrile provided optimal resolution, while maintaining excellent reproducibility. That buffer provided high resolution of wheat and oat prolamins. Resolution of rice prolamins also improved using that buffer, but best resolution of rice prolamins was found when lauryl-sulfobetain at its critical micelle concentration (26 mM) was also added.