Evaluation of Internal Standard Inclusion for Qualitative Analysis of Seized Drugs using DART-MS

Published

December 18, 2021

Author(s)

Edward Sisco, Amber Burns, Elizabeth Schneider, Ikenna Ikpeama

Abstract

Rapid and accurate screening tools for seized drug analysis continue to be needed due to the complexities associated with the emerging drug landscape. Direct analysis in real-time mass spectrometry (DART-MS) is one technique that has been used for this purpose and is seeing increased implementation due to its ability to provide high-fidelity information rapidly. As with any analytical technique ensuring data integrity with DART-MS results is critical. To further enhance data integrity and eliminate some of the challenges associated with qualitative seized drug analysis using DART-MS the incorporation of internal standard was investigated. After evaluating a number of candidate compounds tetracaine was chosen because of its desirable characteristics. An appropriate concentration of tetracaine was established that provided similar sensitivity to GC-MS for a panel of drugs. The presence of tetracaine in a drug extract was found to cause a reduction in signal for some common drugs due to competitive ionization but did not cause complete suppression of signal at relevant concentrations. Evaluation of a set of 60 representative case samples with and without internal standard found that the presence of internal standard did not negatively impact the results and that its presence eliminated the false identification of noise peaks in negative samples. The use of an internal standard also provided within-sample mass calibration and analyte concentration checks. It also allowed for automated mass drift compensation, removing a time-consuming process for high resolution DART-MS data processing.

Citation

Forensic Chemistry

Volume

27

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.forc.2021.100392

Local Download

Keywords

DART-MS, Seized Drug, Internal Standard, Qualitative Analysis, Competitive Ionization

Citation

Sisco, E. , Burns, A. , Schneider, E. and Ikpeama, I. (2021), Evaluation of Internal Standard Inclusion for Qualitative Analysis of Seized Drugs using DART-MS, Forensic Chemistry, [online], https://doi.org/10.1016/j.forc.2021.100392, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932522 (Accessed March 13, 2025)