analysis of accelerants in fire debris by capillary gas liquid chromatography

136 Pages·2003·1.86 MB·English

by  A. D. Cafe

ANALYSIS OF ACCELERANTS IN FIRE DEBRIS
BY CAPILLARY GAS LIQUID CHROMATOGRAPHY
ANTHONY D. CAFE
B. APP. SC. (HONS). (NSWIT)
DEPARTMENT OF MATERIAL SCIENCE
UNIVERSITY OF TECHNOLOGY SYDNEY
JUNE, 1988.
The experimental work involved in this project has been aimed at
developing an understanding of the problems likely to be
encountered during the routine analysis of fire debris where the
analytical technique is capable of detecting approximately one-
microlitre of an accelerant. This high sensitivity is achieved by
analysing with Capillary Gas Liquid Chromatography a dynamic
headspace extract of the fire debris.
Capillary columns are being used more extensively in G.L.C.
analysis because of their greater resolving power as compared to
packed columns. They have been slowly accepted in routine fire
debris analysis but were used exclusively throughout the project
and were found to give more information in the chromatograms to
aid their interpretation. There has also been reservations about
using techniques that are capable of detecting 1 pL of accelerant
because of the questions of the normal background levels of the
accelerants, the possibility of contamination and the interpretation
of the chromatograms and these three areas were investigated.
Background levels of accelerants on various materials were
monitored, areas where the accidental contamination of the sample
is possible were identified and alternative techniques proposed and
chromatograms using capillary columns of various accelerants,
synthetic and household materials are presented which would aid
the interpretation of a samples' chromatogram. The chemical
characteristics of these materials were also investigated using
specific ion monitoring of the chromatographic analysis.
The efforts of the forensic laboratory are reliant on the quality of
the samples provided so the suitability of a sampling aid the
"Sniffer" was evaluated and the insimment's shortcomings are
discussed.
Techniques of identifying gas odourants utilising the equipment
used for fm debris analysis are also presented which would assist
the investigation of explosions.
The project also investigated the problems of the analytical
discrimination of accelerants when using dynamic headspace
analysis which would aid the interpretation of the chromatograms.
Static headspace analysis was also examined using Tenax
absorption tubes and the method could also be used in the
laboratory to enable greater flexibility of operation.
"Our acts are attached to us
As its glimmer is to phosphorous.
They consume us, it is true,
But they make our splendour."
Andre Gide
ACKNOWLEDGEMENTS;
This project was conducted in the Geronimo Fire Investigation
Laboratory at the University of Technology, Sydney. The
laboratory is managed by Insearch Ltd and was initially funded
with a generous grant from the G.I.O. and N.R.M.A. Insurance
Companies. I would like to express my deepest gratitude to these
companies for their financial and continual support and in
particular the G.I.O. for their scholarship, which allowed me to
financially survive to persist with the project.
The driving force behind the laboratory is my co- supervisor Dr.
R.F.G. MacMillan, Head of the Department of Material Science.
I would like to thank Rob for his vision, resilience and inspiration.
My other co- supervisor, Dr. J.H. Sharp, Senior Lecturer of the
Department of Chemistry has impressed on me a sense of
diligence and finesse in my work which I am greatly indebted to
him for.
Finally I would like to thank all the academic and technical staff
at the University and in particular Mr. Jim Keegan for the
comments and advice he gave.
TABLE OF CONTENTS:
Page
ABSTRACT
ACKNOWLEDGEMENTS
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
CHAPTER 1. INTRODUCTION
1.1 Arson Investigation
1.2 Determining the Fire Cause
1.3 The Nature of Accelerants
1.4 Sampling at the Fire Scene
1.5 Control Samples
1.6 Use of the "Sniffer" at the Fire Scene
1.7 The Importance of Accelerant Analysis
1.8 Fire Debris Extraction and Analysis
1.8.1 Extraction Techniques
1.8.2 Properties of Absorbents
1.8.3 Desorption Techniques
1.8.4 Analytical Techniques
(0 Principle of G.L.C.
CMAF'JTR 2. THE EXPERIMENTAL WORK OBJECTIVE
2.1 The Extraction Equipment
2.2 The Analytical Equipment
CHAPTER 3. EXPERIMENTAL RESULTS AND DISCUSSION
3.1 Sampling with a Sniffer
3.2 Contamination of Samples
3.2.1 Precontamination of Containers
(0 Analysis of Empty Cans
(ii) Cleaning of Cans
3.2.2 Contamination During Transpon
and Storage
3.2.3 Contamination During Analysis
(0 Investigation of the
Water Trap
(ii) Gas Transfer Line Material
(iii) Cleaning of the Gas
Transfer Lines
(iv) Syringe Cleaning Procedures.
3.3 Discrimination During Extraction.
3.4 Thermal Desorption Using Tenax
(0 Analysis of Petrol
(ii) Analysis of Ethanol
3.5 Detection of Gas Odourants
3.5.1 Investigation of a Suitable
Absorbent for the Analysis of Gas
3.5.2 Use of Dragar Tubes OnSite to
detect Gas Odourants.
3.6 Interpretation of Results
3.6.1 Background Levels of Accelerants
3.6.2 Analysis of the Common Accelerants
(0
Petrol
(ii) Petrol Additives
(iii) Kerosene
(iv) Mineral Turps
(v) Diesel
3.6.3 Analysis of the Industrial Solvents
(i) Lacquer Thinners
(ii) Methylated Spirits
(iii) Shell Solvents
3.6.4 Analysis of Common Household
Products and Materials
(i) Floor Tile Glue
(ii) Varnished Wood
(iii) Motor Oil
(3 Vegetable Oil
(v) Aerosol Sprays - Mortein
& WD-40
3.6.5 Analysis of Burnt Synthetic Materials
(0 Nylon
(ii) Polyvinylchloride (P.V.C)
(iii) Polvethvlene
(ivj ~oi~rd~ylene
(v) Polystyrene
(vi) Rubber backed carpet
(vii) Rubber floor tiles
CHAPTER 4. CONCLUSIONS
BIBLIOGRAPHY
APPENDIX 1 CHROMATOGRAMS OF THE
INDUSTRIAL SOLVENTS.
LIST OF FIGURES;
Extraction Equipment
Schematic Diagram of Dynamic Headspace
Extraction Equipment
Empty Can Chromatogram
Lined Can vrs Petrol Chromatograms
Plastic Bag Chromatogram
Diesel extracted and sampled at 15, 30, 60 and 90
minutes vrs Diesel Chromatograms
Thermal and Solvent Desorption of Petrol
Chromatograms
Thermal and Solvent Desorption of Ethanol
Chromatograms
Town Gas Chromatogram
Soil (Ex Motor Yard) vrs Petrol and Diesel
Chromatograms
Fresh and Evaporated Petrol Chromatograms
Ion Scans of Petrol Chromatogram
Lead Scans of Petrol Chromatogram
Lead Scans of Extracted Petrol Chromatogram
Leaded and Unleaded Petrol Chromatograms
Kerosene Chromatogram
Ion Scans of Kerosene Chromatogram
Evaporated Kerosene vrs Diesel Chromatograms
Fresh and Evaporated Mineral Turps Chromatograms
Ion Scans of Mineral Turps Chromatogram
Diesel and Evaporated Diesel Chromatograms
Ion Scans of Diesel Chromatogram
Floor Tile Glue vrs Petrol Chromatograms
Varnished Wood vrs Petrol Chromatograms
Motor Oil vrs Kerosene Chromatograms
Vegetable Oil and Rancid Oil Chromatograms
Mortein, WD40 vrs White Spirits Chromatograms
Burnt Nylon Chromatogram
Burnt P.V.C Chromatogram
Ion Scans of Burnt P.V.C Chromatogram
Burnt Polyethylene vrs Kerosene Chromatograms
Ion Scans of Burnt Polyethylene Chromatogram
Burnt Polypropylene Chromatogram
Burnt Polystyrene Chromatogram
Ion Scans of Burnt Polystyrene Chromatogram
Burnt Rubber Backed Carpet vrs Petrol
Chromatograms
Ion Scans of Burnt Rubber Backed Carpet
Chromatogram
Burnt Rubber Floor Tile Chromatogram
Ion Scans of Burnt Rubber Floor Tile Chromatogram
LIST OF TABLES;
Sniffer Responses for 112 Samples
Drager Tube Responses to H2S, T.H.T., T.B.M. and
Diluted Town Gas.