Determination of beta-(3,4-dihydroxyphenyl) lactic acid, protocatechuic acid and protocatechuic aldehyde in radix Salviae Miltiorrhizae by capillary electrophoresis

The separation and determination of beta-(3,4-dihydroxyphenyl) lactic acid, protocatechuic acid and proto catechuic aldehyde in Radix Slviae Miltiorrh izae injection were investigated by capillary zone electrophoresis. With bo ric acid (200 mmol L-1) adjusted to pH 8.11 as a background electrolyte, 28 kV applied voltage and 30 degrees C thermostating temperature, complete se paration of beta-(3,4-dihydroxyphenyl)lactic acid, protocatechuic acid and protocatechuic aldehyde was readily achieved within 9 min. Results indicate that capillary electrophoresis promises to be applicable to quality contro l of radix Salviae Miltiorrhiza injection.