Degraded Ignitable Liquids Database: An Applied Study of Weathering and Bacterial Degradation on the Chromatographic Patterns of ASTM E 1618 Ignitable Liquid Classes

• NCJ Number: 250468
• Author(s): Michael E. Sigman; Mary Williams
• Date Published: December 2016
• Length: 105 pages
• Grant Number(s): 2011-DN-BX-K539
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored); Program/Project Description
• Award: Degraded Ignitable Liquids Database: An Applied Study of Weathering and Bacterial Degradation on the Chromatographic Patterns of ASTM E 1618 Ignitable Liquid Classes

Annotation

This study examined the effects of weathering and biological degradation on ignitable liquids from each of the ASTM E1618 designated classes.

Abstract

Each of the weathered and degraded samples was added as a new record in the Ignitable Liquids Reference Collection (ILRC) database. The ILRC database was modified to link all associated records from weathering and degradation of the same ignitable liquid. The data from all of the samples were reviewed by the ILRC Committee and evaluated regarding the potential impacts of weathering and biological degradation on the interpretation of fire debris data. A "Best Practices" statement was prepared by the ILRC Committee and placed on the ILRC database web site. This statement will inform forensic practice and policy in laboratories that conduct fire debris analysis The evaporation rates were also modeled as a function of the fraction weathered and found to follow first-order kinetic profiles. The natural logarithm of the fitted rate constants were found to exhibit varying degrees of linearity as a function of retention index. The kinetic analysis is a preliminary investigation that may provide direction for future attempts to implement a digital weathering algorithm that would aid fire debris analysis in predicting, a prioiri, the chromatographic profiles of weathered ignitable liquids. The study's methodology involved the weathering of 50 ignitable liquids in the ILRC database by 0, 0.25, .5, 0.75, 0.9, and 0.95 fractions of the original volume. The same liquids were biologically degraded on potting soil for 0, 7, 14, and 21 days. 33 figures, 22 tables, 42 references, and appended list of ignitable liquids in the study, "Best Practices," biologically degraded samples in the Ignitable Liquids Database, and example calculation of TPR, FPR, and accuracy for AR from table 11