Quantitative LC-MS/MS Analysis of Amphetamines and Cocaine in Human Urine

We hereby present a fast and high-throughput LC-MS/MS assay for the simultaneous analysis of amphetamines and cocaine in human urine. The assay is used for confirmations following immunoassay urine drug screens as well as a quantitative assay to report actual urine concentrations in the range 30-10,000 ng/mL for each of the seven analytes, namely, amphetamine; methamphetamine; phentermine; methylenedioxyamphetamine; 3,4-methylenedioxymethamphetamine; methylenedioxy-ethyl-amphetamine; and a cocaine metabolite, benzoylecgonine. The assay derives its efficacy from minimal sample preparation via dilute and shoot. The platform is based on reversed-phase liquid chromatography coupled to the TSQ Endura triple-quadrupole (QqQ) MS instrument for detection via electrospray ionization multiple-reaction monitoring MS. The quantitative analysis is based on the linear calibration whereby the instrument response for each analyte at a given concentration is normalized against stable isotope-labeled internal standard. In addition, the assay can be multiplexed across more than one LC channel to obtain high-sample throughput.