Based on the phenomenon that metoclopramide (MCL) could consumingly enhance the electrochemiluminescence (ECL) intensity of tris(2,2 -bipyridyl)ruthenium , a novel and sensitive method was proposed for determination of metoclopramide using capillary electrophoresis (CE) coupled with electrochemiluminescence (ECL) detection. The influence of several experiment parameters was explored. The optimum experimental conditions were detection potential 1.18 V (vs. Ag/AgCl), 40 mmol/L of phosphate buffer (pH 7.2) containing 5 mmol/L in CEL detection cell, running buffer of 20 mmol/L (pH 6.1), sample injection of 10 s at 12 kV, and separation voltage of 14 kV. The detection limit (3σ) of this method was 5.0×10^－3 mg/L. The linear range of ECL intensity versus concentration of metoclopramide was 0.03～9.52 mg/L, and the correlation coefficient was 0.9990. The recovery of testing 5 standard samples by this method was 98.0%～101.7%. Maximum of MCL concentration in Dog Plasma appeared at 1.5 h of drugging, and half life of the concentration was about 4 h. This method had the merits of simpleness, speediness, sensitivity, little sample injection, and could successfully avoid the influencing of interference. This method was successfully utilized to the assay of metoclopramide in dog plasma.

Key words: capillary electrophoresis, electrochemiluminescence, metoclopramide, plasma drug concentration