morphinans and ferric-ferrocyanide

A Ru(bpy)(3)(2+)-based electrochemiluminescence (ECL) detection coupled with capillary electrophoresis (CE) has been established for the determination of sinomenine for the first time. Optimum separation was achieved with a fused-silica capillary column (50 cm x 25 microm i.d.) and a background electrolyte of 50 mM sodium phosphate (pH 5.0) at a separation voltage of 15 kV. The content of sinomenine was detected by ECL at the detection voltage of 1.15 V (versus Ag/AgCl) with 5 mM Ru(bpy)(3)(2+) in 75 mM phosphate solution (pH 8.0) when a chemically modified platinum electrode by europium(III)-doped prussian blue analogue (Eu-PB) was used as a working electrode. Under the optimized conditions, the ECL intensity was in proportion to sinomenine concentration in the range from 0.01 to 1.0 microg mL(-1) with a detection limit of 2.0 ng mL(-1) (3sigma). The relative standard derivations of migration time and ECL intensity were 0.93 and 1.11%, respectively. The level of sinomenine in Sinomenium acutum Rehd. et Wils was easily determined with recoveries between 98.6 and 102.7%.

Topics: Calibration; Electrochemistry; Electrodes; Electrolytes; Electrophoresis, Capillary; Ferrocyanides; Hydrogen-Ion Concentration; Luminescence; Medicine, Chinese Traditional; Morphinans; Phosphates; Plant Extracts; Platinum; Rubidium; Solvents