Simultaneous determination of lappaconitine hydrobromide and isopropiram fumarate in rabbit plasma by capillary electrophoresis with electrochemiluminescence detection

A CE electrochemiluminescence ( CE – ECL ) method for simultaneous determination of lappaconitine hydrobromide ( LH ) and isopropiram fumarate ( IF ) has been first established, with a chemically modified platinum electrode by europium ( III )‐doped P russian blue analogue film as a working electrode. The conditions for CE separation and ECL detection are discussed and optimized in detail. It has been proved that 20 mmol/L phosphate buffer (p H 8.5) containing 5% (v/v) ACN and 0.17 mol/L SDS could achieve the most favorable resolution, and the high sensitivity of detection was obtained by maintaining the detection potential at 1.23 V. Under optimized conditions, a baseline separation for the two analytes was achieved within 6 min, and the standard curves were linear in the range of 1.0×10 −7 ∼ 5.0 × 10 −5 g/mL for LH and 4.0 × 10 −8 ∼ 1.0 × 10 −5 g/mL for IF with the detection limits (3σ) of 6.6 × 10 −8 g/mL for LH and 3.7 × 10 −8 g/mL for IF , respectively. The precisions of intra‐ and interday measurements for LH and IF were less than 4.21 and 2.61%, respectively. The applicability of the proposed method was illustrated in the determination of LH and IF in rabbit plasma with recoveries between 95.6 and 103.0%.