Development of a data processing method for non-target liquid chromatography– tandem mass spectrometry drug analysis using available online software and databases

We developed a data analysis method for non-target liquid chromatography–tandem mass spectrometry (LC-MS/MS) drug analysis by combining software and databases available online. Blood and urine samples from deceased persons were analyzed using LC-MS/MS in data-dependent acquisition mode. Full-scan data were extracted and output as a two-dimensional (2D) plot (x-axis: retention time; y-axis: m/z value) using the data analysis software MZmine3. Multiple 2D plots were overlaid using image processing software, and distinct peaks unique to the sample of interest were selected. The MS/MS spectra of these distinct peaks were matched against databases using the MS-DIAL software. The databases used for matching included publicly available resources, as well as a compilation of MS/MS spectra of substances relevant to forensic toxicology. The analysis led to the detection of unexpected drugs. To enhance the effectiveness of database matching, it will be crucial to improve the database by sharing MS/MS spectra among drug-testing institutions.