Analysis of opiates, cocaine and metabolites in urine by high-performance liquid chromatography with diode array...

An analytical method is proposed for the simultaneous determination of morphine, codeine, 6-acetyl-morphine (MAM), cocaine, benzoylecgonine (BEG), cocaethylene, methadone and 2-ethylen-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in urine using high performance liquid chromatography coupled to a diode array detector (HPLC-DAD). The selection of working wavelengths is based on the highest chromatographic response for each component: 233 nm for cocaine, BEG and cocaethylene; 285 nm for morphine, codeine and MAM; and 292 nm for methadone and EDDP. The mobile phase, which is a mixture of acetonitrile and 0.02 M phosphate buffer at pH 6.53, was eluted in gradient mode through an XTerra RP-8 column (250 mm x 4.6 mm i.d., 5 microm particle size). After applying a solid-phase extraction procedure with Bond Elut Certify cartridges, the recoveries obtained were between 60% (EDDP) and 97% (cocaethylene). A good linearity of the method in the 0.1-10 microg mL(-1) range of urinary concentrations was obtained because the coefficient of correlation exceeded 0.99 for each drug. The precision and accuracy were quite good, with values of <7% and within the range +/- 6%, respectively. Finally, the proposed method was applied to 23 urine samples from fatal intoxications related to methadone, heroin and[sol ]or cocaine.