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

A CE electrochemiluminescence (CEECL) 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 Prussian 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 (pH 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 1.0x10-7 similar to 5.0 x 10-5 g/mL for LH and 4.0 x 10-8 similar to 1.0 x 10-5 g/mL for IF with the detection limits (3s) of 6.6 x 10-8 g/mL for LH and 3.7 x 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%.