On-site quantitation of morphine in urine by fast derivatization and miniature mass spectrometry analysis

Analysis of drugs in urine is particularly useful for screening of public safety issues, monitoring of medicine appliance and detection of drugs of abuse. Tandem mass spectrometry (MS/MS) of morphine usually produces clusters of fragments, hindering accurate quantitation of morphine in biological samples by fast sampling and direct MS/MS method. In this work, we developed a method that enabled determination and quantitation of morphine in urine in 3 min. It consisted of a simple extraction process, a fast dansyl-derivatization process, and direct analysis by a miniature mass spectrometer. MS/MS of derivatized morphine produced a highly abundant product at m/z 285 in positive ion mode, significantly enhancing the sensitivity by more than 10 times. Quantitation of morphine in urine was achieved by in-trap collision-induced dissociation on the miniature mass spectrometer, with the limit of detection of 50 ng/mL and the limit of quantitation of 100 ng/mL. The performance of the method was also evaluated with a standard liquid chromatography-MS method, showing comparable quantitative accuracy. Finally, the method has applied into quantitation of morphine in real urine samples from individuals suspected to have used opioids.