Addressing the Oxygen in the Room: Exploring the Formation of Oxygenated Species for Nitazene Analogs Using DART-MS

Direct analysis in real time-mass spectrometry (DART-MS) is a technique well suited for screening seized drug samples as it enables rapid analysis with minimal sample preparation. Therefore, information present in full scan mass spectra is extremely important and can indicate the presence of controlled substances in a sample. This study explores the formation of oxygenated species in the full scan mass spectra of 18 nitazene analogs, as well as a few other seized drug-related compounds. Generally, with helium as the source gas, an [M+H+O-2H]⁺ (i.e., +14 Da) ion was present, and with nitrogen as the source gas, an ion representing [M+H+O]⁺ (i.e., +16 Da) was observed. However, certain compounds, such as tetracaine, contained a +16 Da ion with helium as the source gas, indicating that both the source gas and chemical properties of the analyte impact oxygenated species formation. Further tandem mass spectrometry (MS/MS) studies were conducted to identify where the oxygen adduct was formed. The presence of a tertiary amine appears to play a role in oxygenation, as oxygenated iminium ions were frequently observed. Overall, oxygenated species were observed at higher abundances for the nitazene analogs than other controlled substances, providing an additional piece of support for a nitazene analog identification using DART-MS.