Hanging by a Thread:

Enhancing the Forensic Value of Dyed Cotton Trace Evidence through
the Application of Novel Techniques in Fiber Discrimination

By: Rachel M Russo
Mentor: Barry Fookes

Appendix

Appendix A: Comparision Microscopy

[Back to Top]

Appendix B: Fiber Examination Protocol

Used by permission from Max Houck (22)

[Back to Top]

Appendix C: Dye Classification Scheme

[Back to Top]

Appendix D: Dyes Classified

 

Group 1

Group 2

Group 3

Sample Number

6

8

3

4

1

2

Fiber type

Cotton

Cotton

Cotton

Cotton

Cotton

Cotton

Color

Red

Red

Red

Red

Red

Red

MSP l max

523, 554nm

523, 554nm

526, 552nm

526, 552nm

523, 550nm

523, 550nm

Dye class

Reactive

Azoic

Direct

Direct

Direct

Direct

Conclusion

Uniquely identified

Uniquely identified

Needs more data

Needs more data

Needs more data

Needs more data

[Back to Top]

Appendix E: MSP Absorption Spectra

Group 1 fibers, while having virtually indistinguishable spectral profiles on the MSP are differentiable by dye class as determined according to the FBI Dye Extraction and Classification Scheme. (Not normalized.)

Group 2 fibers cannot be discriminated by MSP and belong to the same dye class; however the LCMS reveals markedly different mass spectral peaks indicative of the divergent chemical structures of the dye compounds.(Not normalized)

Group 3 fibers have matching spectral profiles on the MSP and contain dyes of the same dye class with similar chemical structures on the LCMS. LIF identifies striking differences in the excitation characteristics of the extracts, distinguishing sample 1 from sample 2. (Normalized)

[Back to Top]

Appendix F: LC-MS Spectra

[Back to Top]

Appendix G: Flourescence Spectroscopy EEM

 

Return to Issue Index