Evidence-based Evaluation of the Analytical Schemes in ASTM E2329-17 Standard Practice for Identification of Seized Drugs for Methamphetamine Samples

Publication

Forensic Chemistry, May 2024

Authors

Jeremy S. Triplett | Kentucky State Police Central Forensic Laboratory
Jeff Salyards | Compass Scientific Consulting
Sandra E. Rodriguez-Cruz | DEA Special Testing and Research Laboratory
Jeremiah A. Morris | Johnson County Sheriff's Office Criminalistics Laboratory
Darryl Creel | RTI International
Joseph Zemmels | Center for Statistics and Applications in Forensic Evidence
Megan Grabenauer | RTI International

Abstract

This study involved 71 forensic seized drug laboratories analyzing 65 total samples; 17 were ground-truth positive (i.e., they contained methamphetamine or cocaine); 48 were ground-truth negative (i.e., they did not contain methamphetamine or cocaine). The positive samples were prepared at several target-analyte concentrations and combined with common cutting agents. The negative samples were designed to be challenging and prepared to contain positional isomers of methamphetamine. Participants were sent two different sample sets. In the first, they were directed to only use a single, pre-selected analytical technique. In the second, they were directed to use a pre-selected analytical scheme consisting of multiple techniques in compliance with ASTM E2329-17. The results of the study showed good accuracy; sensitivity was 1.000 for all analytical schemes with 1- specificity (the false-positive rate) ranging from 0.000 to 0.250 when ASTM E2329-17 compliant analytical schemes were used. When only a single technique was used, accuracy was generally not as good; sensitivity ranged from 1.000 to 0.091, and 1-specificity ranged from 0.000 to 0.245.