Determination of ascorbic acid in human plasma by high-performance liquid chromatography with electrochemical...

Ascorbic acid (AA) was determined in human plasma by high-performance liquid chromatography with electrochemical detection using a hydroxyapatite cartridge for plasma deproteinization. The proposed method is simple, rapid (deproteinization time, within 1 min; analysis time, ca. 15 min), sensitive [detection limit, ca. 240 ng/ml plasma (at a signal-to-noise ratio of 2:1)], highly selective and reproducible [relative standard deviation, ca. 2.8% (n = 3)]. The calibration graph for AA was linear in the range 0.1-10 ng per injection (20 microliters). The recovery of AA was over 90% by the standard addition method.