1. Direct Thermal Extraction of
Volatiles from
Black Electrical Tape
Emily Prisaznik, B.S.
Cedar Crest College
Thomas A. Brettell, Ph.D., F-ABC

2. Disclosure
The author has no financial or other
relationship with the manufacturer of any
commercial products or providers of any
commercial service or supporters.

3. Forensic Relevance
■ Tape samples/specimen
■ Source or scene
https://www.bostonglobe.com/2015/03/26/tsarnaev-jury-expected-hear-more-about-
bombs-used-during-boston-marathon-attacks/WDLMcNBtpKrsHmNSaNQuDO/story.html

4. Forensic Relevance
■ GC/MS
– characterize data by comparing chromatograms
■ PyGC/MS
– characterize adhesives from IEDs

5. Goals
■ Organic volatiles from black electrical PVC tape
■ Develop a TE-PyGC/MS method
■ Thermally extract tape samples with pyrolysis
probe

6. Thermal Extraction GC
Methods
■ Analytical Pyrolysis
■ Thermal extraction
■ Thermal desorption
*Slide Courtesy of T. Wampler, Chemical Service Systems

7. Analytical Pyrolysis
■ Volatilize small molecules
■ Thermal Desorption, Purge & Trap
– 50-200oC
■ Pyrolysis of non-volatile material
– 350-800oC
■ Pyrolysis
– molecular degradation mechanism
– thermal energy
■ Heat breaks molecules apart
*Slide Courtesy of T. Wampler, Chemical Service Systems

8. Pyrolysis
■ Chemical decomposition
– condensed substance
– heating
■ Incineration
– chemically decomposes organic material
– heat in the absence of oxygen
*Slide Courtesy of T. Wampler, Chemical Service Systems

9. Pyrolysis GC/MS
*Slide Courtesy of T. Wampler, Chemical Service Systems

10. Literature Survey
■ Analysis and discrimination of electrical tapes:
part I. adhesive.
– Mehltretter AH, Bradley MJ, Wright DM. J Forensic
Sci 2011;56(1):82-94.
■ Analysis and discrimination of electrical tapes:
part 2. backing.
– Mehltretter AH, Bradley MJ, Wright DM. J Forensic
Sci 2011;56(6): 1493-504.

11. Tape Samples
- National Forensic Tape File, FBI

12. Analysis and discrimination
of electrical tapes
■ SEM
– Adhesives: 17%
– Backing: 87.3%
■ FTIR
– Adhesives: 67%
– Backing: 83.3%
■ Py-GCMS
– Adhesives: 83%
– Backing: 81.0%
Mehltretter AH, Bradley MJ, Wright DM. Anaysis and discrimination of electrical tapes: part I. adhesives. J Forensic Sci 2011:56(1):82-94.
Mehltretter AH, Bradley MJ, Wright DM. Analysis and discrimination of electrical tapes: part II. backings. J Forensic Sci 2011:56(6): 1493-
504.

13. Determination of Off-Odors and Other
Volatile Organics In Food Packaging
Films By Direct Thermal Analysis-GC-MS
■ 100-mg packaging film
■ Desorption at 100°C for 10min
■ Cryofocused at -40°C
■ Ramped to 280°C at 10°C
Hartman T. Determination of off-odors and other volatile organics in food packaging films by direct thermal analysis-GC-MS. Ringoes (MD):
Scientific Instrument Service; 2000 Jan. Application Note #1.

14. What makes this project
significant?
■ PVC tape plasticizers
– Thermally desorb
– Low temperatures & initial pyrolysis

15. Internal Components
http://www.sisweb.com/catalog/36/C80
GC/MS with SIS
AutoDesorb™2000

16. Method
Thermal Desorption
■ Desorb 150°C for 10min
■ Approximately 20-40 mg
samples
■ 4 mm I.D. Glass lined tubes
http://www.sisweb.com/art/pdf/autodeso.pdf

17. Sample “Prep”

18. Method
GC/MS
■ GC Agilent 6890N
■ MS Agilent 5976MS
■ Electron Ionization Mode (70 eV)
■ 35-650 m/z mass scan range
■ 3.15 scans/sec

19. Method
Gas Chromatography
■ Zebron ZB-1HT®
(30 m x 0.25 mm I.D. x 0.25 µm)
30°C (2 min)
– 50°C @ 10°C/min
– 240°C at 2°C/min
– 280°C @ 10°C/min
5 min (hold)
■ Injector Temp 150°C
■ Helium flow rate 1.0 mL/min

20. Optimizations
■ Desorption Temperature
– 150°C
– 175°C
– 220°C
■ Sample Size
– SIS
– FBI
■ GC Temperature Programs

21. BII 17July2015
22.3 mg
Zebron ZB-1HT®
1-Decene
Hexadecanoic acid,
methyl ester
Octadecanoic acid,
methyl ester
Hexanediotic acid,
dioctyl ester

22. BII 23July2015
22.2 mg
1-Decene
Hexadecanoic acid,
Methyl ester
Octadecenoic acid,
Methyl ester
Hexanediotic acid,
dioctyl ester
Zebron ZB-1HT®

23. BII 23July2015
33.2 mg
1-Decene
Hexadecanoic acid,
methyl ester
Octadecenoic acid,
methyl ester
Hexanedioic acid,
dioctyl ester
Zebron ZB-1HT®

24. BII
33.2 mg
23July2015
BII
22.2 mg
23July2015
BII
22.3 mg
17July2015
1-Decene
Hexadecanoic acid,
methyl ester
Octadecenoic acid,
methyl ester Hexanedioic acid,
dioctyl ester

25. Conclusion
■ Smaller sample size
■ Reproducible at 150°C
■ Semidestructive
■ Inter- and Intra- day correlations

26. Continuing Research
■ Multiple tape samples
■ Evaluate desorption temperatures
■ TE-py-GC/MS
■ FBI tape samples

27. Acknowledgements
■ Cedar Crest College
■ Dr. Thomas Brettell
■ Mr. Thomas Prichett
■ Dr. Larry Quarino
■ Dr. Diana Wright, FBI
■ Family & Friends

28. Thank you!
Email: eeprisaz@cedarcrest.edu