Citation

Waddell EE, Williams MR, Sigman ME. J. Forensic Sci. 2014; 59(4): 927-935.

Affiliation

Department of Chemistry, University of Central Florida, Orlando, FL, 32816.

Copyright

(Copyright © 2014, American Society for Testing and Materials, Publisher John Wiley and Sons)

DOI

10.1111/1556-4029.12417

PMID

24502629

Abstract

A multistep classification scheme was used to detect and classify ignitable liquid residues in fire debris into the classes defined by the ASTM E1618-10 standard method. The total ion spectra (TIS) of the samples were classified by soft independent modeling of class analogy (SIMCA) with cross-validation and tested on fire debris. For detection of ignitable liquid residue, the true-positive rate was 94.2% for cross-validation and 79.1% for fire debris, with false-positive rates of 5.1% and 8.9%, respectively. Evaluation of SIMCA classifications for fire debris relative to a reviewer's examination led to an increase in the true-positive rate to 95.1%; however, the false-positive rate also increased to 15.0%. The correct classification rates for assigning ignitable liquid residues into ASTM E1618-10 classes were generally in the range of 80-90%, with the exception of gasoline samples, which were incorrectly classified as aromatic solvents following evaporative weathering in fire debris.

Language: en