Direct Determination of Ephedrine Alkaloids and Epinephrine in Human Urine by Capillary Zone Electrophoresis

The complete separation of a mixture of six phenylamines and epinephrine in human urine was achieved by Capillary Zone Electrophoresis (CZE) in 15 min. For the CZE separation of the compounds, electrophoretic media with phosphate-borate and phosphate-acetonitrile buffer at different pH were used. A buffer solution that contained 40 mM phosphoric acid and 10 mM boric acid adjusted to pH 9.7 with NaOH 1 N, was found to be the most suitable electrolyte forepinephrine separation. The results successfully demonstrated the use of CZE with UV detection for screening and quantification of phenylamines and epinephrine in human urine without previous treatment, in concentration lower than 35.0 μg/ml, and quantification limit of 2.0±0.1 μg per millilitre of urine.