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Ultrafast separations of cereal proteins by high performance capillary electrophoresis. S. R. BEAN (1)
and G. L. Lookhart (2). (1) Kansas State University, Dept. of Grain Science and Industry, Manhattan, KS
66506; (2) US Grain Marketing and Production Research Center, Manhattan, KS 66502.
Free zone capillary electrophoresis conditions have been improved to
allow rapid separations of grain proteins from several cereals (wheat, oats, rice, barley, and rye) with high
resolution and reproducibility. Gliadins were separated in < 8 min, oat and rice prolamins in < 2 min, and
barley prolamins in < 4 min. Glutenins were separated in ~ 3 min, oat and rice glutelins in <3 min, and rye
glutelins in <4 min. This method utilized the isoelectric compound, iminodiacetic acid (IDA) in conjunction
with acetonitrile and hydroxypropylmethyl-cellulose. Cultivars of all cereals tested could be differentiated
in 3 min, including wheat using either prolamin or glutelin protein patterns. Resolution was similar, or
higher, than that of separations in other acidic buffers. Migration time repeatability was excellent with
run-to-run variability <1% relative standard deviation (RSD), day-to-day <1.4% RSD, and capillary-to-capillary
<3.3% RSD. Larger inner diameter capillaries (50 µm) could be used with this buffer thereby increasing
sensitivity and reducing rinse times. This method allows unattended, high throughput (~180 to 400
samples/24 hours) separations of cereal proteins without generating organic solvent waste and allows
automated data analysis and storage.
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