Determination of Tetrandrine in Plasma of Mice by Capillary Electrophoresis-Electrochemiluminescence

The plasma sample was extracted with CHCl3,and the extract was evaporated to dryness by blowing with nitrogen gas at 60 ℃.The residue was taken up with 500 μL of CH3OH,introduced electrically into the capillary and separated by electrophoresis under the conditions of ① voltage of sample introduction: 12 kV;② time of sample introduction: 7 s;③ voltage for separation: 15 kV;④ electrophoretic buffer solution: 20 mmol·L-1 PBS (pH 7.5).Electrochemiluminescence (ECL) was used as method of detection in combination with the capillary electrophoretic separation.The ECL reaction was carried out in a 400 μL-ECL cell containing 5 mmol·L-1 Ru(bpy)2+3 solution and 50 mmol·L-1 PBS (pH 8.0),with a detection potential of 1.15 V (vs.Ag/AgCl).Linear relationship between values of ECL intensity and mass concentration of tetrandrine was kept in the range from 0.05 to 80.0 mg·L-1,with detection limit (3S/N) of 0.02 mg·L-1.Results of recovery test were found in the range of 93.3% to 95.0%.