Tandem DART™ MS Methods for Methadone Analysis in Unprocessed Urine

Current methods of methadone analysis in untreated urine are traditionally limited to enzyme immunoassays (EIA) while confirmation techniques require specimen processing (i.e., sample clean-up) before analyzing by gas or liquid chromatography coupled with mass spectrometry (GC-MS or LC-MS-MS). EIA and traditional confirmation techniques can be costly and, at times inefficient. As an alternative approach, we present Direct Analysis in Real Time (DART™) coupled with both time-of-flight and triple quadrupole linear ion trap (Q-TRAP™) mass spectrometers for screening and confirming methadone in untreated urine specimens. These approaches require neither expensive kits nor sample clean-up for analysis. More importantly, the total combined analysis time for both screening and confirmation methods was <5 min per sample; in contrast to the 3-5 day process required by traditional EIA, GC-MS and LC-MS-MS techniques. To examine the fundamental protocol and its applicability for routine drug screening, studies were performed that included limits of detection, precision, selectivity and specificity, sample recovery and stability and method robustness. The methods described in this report were determined to be highly specific and selective; allowing for detection of methadone at 250 ng/mL, consistent with cutoffs for current EIA techniques (300 ng/mL). The results reported here demonstrate the DART™ MS platform provides rapid and selective methadone analysis and the potential for providing savings of both time and resources compared with current analysis procedures.