|SOFT - TIAFT 1998||Poster Session 4||Friday October 9, 1998|
LSD CASEWORK AT THE RCMP LABORATORY: SCREENING OF PRE AND POST-MORTEM BIOLOGICAL SPECIMENS BY RIA, EMIT AND ELISA AND CONFIRMATION BY GC/MS OR GC/MS/MS|
Marthe Dalpé-Scott, Douglas J. McClure, Brian J. Perrigo and Michelle L. Roy
Royal Canadian Mounted Police, Central Forensic Laboratory, P.O. Box 8885, Ottawa, ON, Canada
|The Royal Canadian Mounted Police forensic laboratory system has been involved in the analysis of LSD in pre and post-mortem fluids (blood, serum, plasma, urine, bile) and tissues (stomach contents, liver homogenates) as well as food extracts for approximately six years.
A number of screening techniques have been evaluated and compared: Abuscreen RIA (Roche Diagnostics Systems), Coat-A-Count RIA (Diagnostics Products Corp.), EMIT II (Syva and Behring Diagnostics) and ELISA (STC Technologies, Inc.). Methanolic extracts of blood, serum and plasma samples were prepared before assay. Fifteen samples previously screened LSD positive by Abuscreen RIA and confirmed by GC/MS were also found to be positive by Coat-A-Count RIA, EMIT and ELISA. However, a number of samples that screened positive by EMIT were not necessarily positive by either RIA assay or ELISA. The EMIT procedure was modified to exclude a large percentage of the false positive samples.
A quantitative confirmation of LSD was initially performed by manual solid-phase extraction followed by GC/MS (Varian 3400 GC coupled to Finnegan TSQ 7000 MS) on the trimethylsilyl derivative of LSD and LSD-d3. The limit of quantitation ranged from 0.25 ng/mL to 0.50 ng/mL. A cleaner, faster and more sentitive confirmation method was then developed using the Zymark Rapid Trace solid phase extractor followed by GC/MS/MS on the trimethylsilyl derivative of LSD and LAMPA. The limit of quantitation was found to be 0.1 ng/mL. The latter method was also modified to accomodate LSD extraction from liver homogenates.
Results from selected criminal cases will be presented.