|We have developed a UPLC-MS/MS method for the determination of the major urinary cocaine metabolites: benzoylecgonine and ecgonine methyl ester, cocaethylene, and the adulterant levamisole and its urinary metabolite 4(OH) levamisole.
We performed these assays on a Waters ACQUITY UPLC with a TQ Detector equipped with a UPLC BEH C18 column using an ammonium acetate/formic acid mobile phase. Urine was extracted using methanol after the addition of Benzoylecgonine-D3, Ecgonine methyl ester-D3, Cocaethylene-D3, and aminorex as internal standards. MS/MS operates with positive Electrospray Ionization (ESI). The assay is run in the MRM mode.