Detection and quantification of tricyclic antidepressants and other psychoactive drugs in urine by HPLC/MS/MS for pain management compliance testing

A sensitive, specific, and rapid high-pressure liquid chromatography/mass spectrometry/mass spectrometry method was developed for the quantitation of 11 tricyclic antidepressants and/or their metabolites; fluoxetine and norfluoxetine; cyclobenzaprine; and trazodone in urine. Samples were alkalinized with 0.2 N NaOH and extracted into 2 ml of hexane: ethyl acetate (1:1), evaporated to dryness, and reconstituted with 100 μl of 20 mM ammonium formate: methanol (20:80). The chromatographic separation was performed using an Allure Biphenyl 100 × 3.2 mm, 5-μ column with a mobile phase consisting of 20 mM ammonium formate: methanol (20:80 v/v) at a flow rate of 0.5 ml/min. The detection was accomplished by multiple-reaction monitoring via electrospray ionization source operating in the positive ionization mode. The calibration curve was linear over the investigated concentration range, 25-2,000 ng/ml, for each analyte using 1.0 ml of urine. The lower limit of quantitation for each analyte was 25 ng/ml. The intra- and inter-day precisions had coefficient of variation less than 15% and the accuracy was within the range from 88% to 109%. The method proved adequate for the tricyclic antidepressants analysis of urine for emergency clinical toxicology and pain management compliance testing.