A fast CE method for the achiral separation of methadone and its major metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline.

The utilization of dynamic doubly coated capillaries for a fast separation of methadone and its two major metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline (EMDP) was investigated. The coated capillaries were prepared using a polycation of poly(diallyldimethylammonium chloride) and a polyanion of dextran sulfate. A fast achiral separation was developed using the coated capillaries with a BGE of 100 mM phosphate buffer at pH 2.6. Complete achiral separation of methadone, EDDP and EMDP was achieved, with migration times of approximately 4 min. The method offers considerable advantages with respect to BGE simplicity and analysis time compared to previously published CE methods for methadone and its related analytes.