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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #122121


item Lookhart, George

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/26/2001
Publication Date: 10/14/2001
Citation: Bean, S.R., Lookhart, G.L. 2001. Optimizing quantitative reproducibility in hpce separations of cereal proteins. Abstract No. 407 in: 2001 AACC Annual Meeting Program Book. p.166. Meeting Abstract.

Interpretive Summary: Presented at the 2001 American Association of Cereal Chemists Annual Meeting held in Charlotte, NC, from October 14-18, 2001.

Technical Abstract: HPCE is capable of producing high resolution, rapid separations of cereal proteins and it is highly reproducible in terms of migration time. However, little work has focused on the quantitative reproducibility of cereal protein separations. Several factors such as sample matrix, sample evaporation, voltage ramp up time, sample injection time, and capillary end cut were evaluated for their involvement in quantitative reproducibility. These experiments showed that preventing sample evaporation, using optimum injection times, and insuring a clean, square cut on the capillary all improved the reproducibility of peak areas. A series of 20 consecutive injections using optimized procedures provided reproducibility with peak areas varying by <1.76% RSD. Migration time reproducibility was also excellent under these conditions, varying only by 0.45% RSD. Other variables such as peak area %, peak height and peak height % also showed good reproducibility with RSD <4%. Increasing the voltage ramp up time from 0.17 to 0.68 was found to increase peak efficiency by about 150%. This factor had no effect on quantitative reproducibility, however. The gradual buildup of contaminants on the capillary walls was found to occur over time and decreased both separation efficiency and reproducibility. Rinsing capillaries periodically with appropriate solvents delayed this effect. Peak efficiency was found to be a good marker for capillary performance and lifetime.