NCJ Number
145900
Journal
Journal of Forensic Sciences Volume: 38 Issue: 6 Dated: (November 1993) Pages: 1354-1362
Date Published
1993
Length
9 pages
Annotation
This paper describes a macro program written for Hewlett Packard Mass Selective Detector data stations that performs data analysis of fire debris samples.
Abstract
The author analyzed samples on a Hewlett-Packard 5890 Gas Chromatograph equipped with a Model 5970 Mass Selective detector. He specifies the gas chromatographic conditions. Data were processed on a UNIX-based data station by running A.01.04 software. The arson analysis program prints the following information: sample header information (case number, analyst name, etc.); the total ion chromatogram; the identification of major peaks; and selected ion profiles for alkane, aromatic, and polynuclear aromatic compounds. Hewlett-Packard data stations are equipped with extensive spectral libraries and use Probability-Based Matching (PBM) search algorithms. By itself, a PBM search cannot discriminate among the mass spectra of many hydrocarbon isomers. To accurately identify a peak in a hydrocarbon mixture, the investigator must do more than just accept the reported best fit from a library search. Many of these problem isomers can be distinguished by their retention times (calculated as a Kovats Index). Thus, a more reliable peak identification will be made by incorporating a retention index filter into the library search procedure. Hewlett-Packard data stations allow for spectral libraries to be created so that the retention index of a compound is saved along with its mass spectra. 3 figures and 6 references