Development of a novel seized drug screening method utilizing DART-MS and used weigh paper

Abstract

The conventional analytical scheme for seized drug analysis utilizes quick and cost-effective presumptive testing, such as color tests, followed by more discriminatory techniques, such as gas chromatography-mass spectrometry (GC–MS). Before the seized drug evidence is analyzed, the evidence is weighed using an appropriate weighing matrix and balance. Typically, the weighing matrix is discarded as chemical waste; however, the process of weighing the evidence leads to the deposition of drug residue onto the weighing matrix, which is then amenable to rapid analysis using ambient ionization approaches, such as direct analysis in real time mass spectrometry (DART-MS). This study demonstrates a DART-MS method for the rapid screening of seized drug evidence using filter paper and glassine paper weighing matrices commonly found in forensic laboratories. Validation experiments were performed using filter paper and glassine paper and compared to the results obtained using glass capillaries to assess the effectiveness of each weighing matrix. A total of 40 authentic samples, 20 filter papers and 20 glassine papers, were analyzed and the resulting spectra were searched using the National Institute of Standards and Technology (NIST) DART-MS Forensics Database and Data Interpretation Tool (DIT). When compared to the ground truth GC–MS results, the developed approach had a 90% correct identification rate, with all misidentifications being due to the presence of tablets rather than powder. The developed DART-MS screening method provides the seized drug community with a method to rapidly screen seized drug residue remaining from the weighing process and to improve the overall laboratory efficiency.