Determination of Amino Acids in Crataegus Pinnatifida by Capillary Electrophoresis Coupled with Field Enhanced Sample Stacking

A method for the amino acid analysis by capillary electrophoresis coupled with field enhanced sample stacking has been developed. This method has been applied to determine the content of hydrolyzed amino acids in Crataegus pinnatifida and the recovery experiment was also carried out. The optimum enrichment and separation conditions are as follows: enrichment voltage is -20 kV, injection time is 50 s (at 3 psi), UV detection wavelength is 214 nm, buffer solution is 270 mmol/L acetic acid-270 mmol/L sodium acetate (pH=4.15)-6% (V/V) acetonitrile, the separation voltage is 17 kV. Twelve amino acids (histidine, arginine, tryptophane, tyrosine, valine, phenylalanine, leucine, threonine, alanine, glycine, glutamic acid and aspartic) were separated and determined simultaneously in 50 minutes under the above optimum conditions. The detection limits (S/N=3) ranged from 0.000 3 to 0.08 μg/mL.