SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A69
FORENSIC DRUG ANALYSIS WITHOUT PRIMARY REFERENCE STANDARDS
Ilkka Ojanpera*, Suvi Laks, Anna Pelander, and Erkki Vuori
Department of Forensic Medicine, P.O. Box 40, FlN-00014 University of Helsinki, Finland
Previously, primary reference standards have been considered essential for substance identification and a
prerequisite for quantitative analysis. However, standards for designer drugs, metabolites or rare substances
cannot be obtained in a reasonable period of time to allow a prompt forensic investigation. This paper
reports a new approach in forensic sciences to characterize drugs without the immediate need of primary
reference standards.
By liquid chromatography - time-of-flight mass spectrometry (LC-TOFMS) or Fourier transform mass
spectrometry (LC-FTMS), it is possible to measure exact molecular masses on a routine basis. Especially
benchtop LC-TOFMS instruments, being more cost-effective, are suitable for high-throughput work.
Modern LC-TOFMS gives a high mass accuracy (approximately 5 ppm) and a moderately high mass
resolution (5000-10000 FWHM). A target library consisting of exact monoisotopic masses for thousands of
drugs and metabolites can be created in-house to determine the elemental formulas of sample components.
This kind of mass list is easily updated by typing recent data from the literature. Even complex biological
samples can be analysed without complete chromatographic separation of the components.
Chemiluminescence nitrogen detector (CLND) possesses an equimolar response to nitrogen, and
consequently it provides a universal means for quantification of nitrogen containing compounds using a
single secondary standard. As approximately 90% of drugs contain nitrogen, CLND is an attractive tool in
forensic sciences. However, the technique has not been used in this area thus far.
In this paper, various critical aspects of LC-TOFMS analysis are discussed. These include internal mass
scale calibration, dynamic range, sensitivity, library search options, isotope pattern analysis, and utilization
of urine metabolic patterns. CLND analysis is discussed in terms of sensitivity, linearity, equimolarity, and
general performance. The merits of LC-TOFMS identification and CLND quantification are demonstrated
in instances, where the availability of standards is a problem, such as in the analysis of street drugs and in
the determination of a plasma parent drug/metabolite ratio.
Keywords: Mass spectrometry, CLND, Drug analysis
Page 183