NCJ Number
209830
Journal
Forensic Magazine Volume: 2 Issue: 2 Dated: April/May 2005 Pages: 20-24
Date Published
April 2005
Length
5 pages
Annotation
This article describes the forensic analytical capabilities of the following technologies: gas chromatography/mass spectrometry with retention time locking (GC/MS/RTL); liquid chromatography/time-of-flight mass spectrometry (LC/MSW/TOF); microfluidic-based capillary electrophoretic analysis of mitochondrial DNA (mtDNA); and laser ablation inductively coupled plasma mass spectrometry (LA/ICP/MS).
Abstract
GC/MS/RTL, although not a new development, is a key innovation in an ongoing wave of "next generation" instruments and software that have significantly improved legally defensible chemical analysis. GC/MS/RTL has been used in forensic toxicology to identify and measure toxins in the human body. LC/MS/TOF is also useful in forensic toxicological analysis given the expansion in the number and variety of drugs being administered by prescription or otherwise. LC/MS/TOF is capable of mass accuracies better than 3 ppm. This high level of mass resolution makes it possible to determine the empirical formula of unknown analytes in full scan mode across the mass range of the instrument. Another forensic tool described in this article draws on advances in microscale fabrication, which has made possible the development of the chemical microchip or lab-on-a-chip. The surfaces of these chips are manufactured with in situ capillary channels, microvalves, and other miniaturized equivalents of laboratory tools arranged in a configuration for securing one or a series of laboratory operations. This technology is used in an instrument designed for the capillary electrophoretic separation and molecular size determination of biomolecules and proteins; it is now being used in the quality assessment of recovered mtDNA pursuant to sequencing. LA/ICP/MS overcomes the preparation problems associated with intractable samples. It performs spatially localized sampling and analysis on a microscale, thereby conserving evidence. 5 figures and 3 notes