Technical note: Evaluation of a transportable linear ion trap mass spectrometer for seized drug screening operated under controlled laboratory conditions

Abstract

Increasing seized drug casework submissions and challenges with rapidly triaging seized drug evidence have led to interest in the potential use of instruments for on-site or mobile laboratory drug screening. However, before this type of instrumentation can be implemented, it is imperative to evaluate the capabilities and limitations under controlled laboratory conditions. This study evaluates the BaySpec Continuity™ transportable linear ion trap (LIT) mass spectrometer coupled to a thermal desorption-atmospheric pressure chemical ionization (TD-APCI) source for seized drug screening while operated under controlled laboratory conditions. The target compounds chosen for this study were selected based on controlled substances and cutting agents commonly observed in seized drug casework, including cocaine, methamphetamine, heroin, fentanyl, caffeine, acetaminophen, pseudoephedrine, phenacetin, phentermine, and levamisole. A library-based alarm system screening method was developed and validated for rapid compound identification in seized drug mixtures. Selectivity, repeatability, and reproducibility were evaluated using five simulated seized drug mixtures with known compositions, and the limit of detection was evaluated for each compound. Blind and authentic destroyed casework samples were analyzed to determine the efficacy of this method when applied to real-world samples and a 100% correct identification rate of the controlled substance present was achieved. Additionally, the ability to differentiate isobaric species using tandem mass spectrometry (MS/MS) analysis was demonstrated for methamphetamine and phentermine. The validated library-based alarm screening method shows promise for rapid seized drug screening under controlled laboratory conditions, which supports potential usage in a mobile laboratory setting.