Luminescence: Lighting the Invisible World of Crime Scenes

Transcription

1 Western Oregon University Digital Academic Excellence Showcase Proceedings Student Scholarship Luminescence: Lighting the Invisible World of Crime Scenes Jessica Alexander Western Oregon University, Follow this and additional works at: Part of the Forensic Science and Technology Commons Recommended Citation Alexander, Jessica, "Luminescence: Lighting the Invisible World of Crime Scenes" (2018). Academic Excellence Showcase Proceedings This Presentation is brought to you for free and open access by the Student Scholarship at Digital It has been accepted for inclusion in Academic Excellence Showcase Proceedings by an authorized administrator of Digital For more information, please contact

2 LUMINESCENCE: LIGHTING THE INVISIBLE WORLD OF CRIME SCENES By Jessica Alexander [1]

3 Overview What is luminescence? Luminescence in forensics The different types of luminescence Evidence found using luminescence

4 What is Luminescence? Electromagnetic Spectrum Emission of electromagnetic radiation Absorbing energy and re-emitting the energy Energy Sources [2]

5 Luminescence in Forensics Types of evidence at crime scenes Emission used to show hidden evidence Find and identify biological fluids Allow for further testing, DNA analysis [3]

6 The Different Types of Luminescence Photoluminescence Alternative Light Sources Chemiluminescence [14] [15] [16]

7 Photoluminescence Fluorescence and Phosphorescence Absorption of photons Energy Well Diagram-Jablonski Diagram

8 Jablonski Diagram [4]

9 Fluorescence vs. Phosphorescence Fluorescence Short-lived (<10-5 s) Emission from singlet state Instantaneous emission Phosphorescence Longer lifetime (seconds-minutes) Emission from triplet state Delayed emission

10 Alternative Light Sources Simple and non-destructive First to be used Color Barrier Filters Effects on DNA [5]

11 Chemiluminescence [4]

12 Types of Latent Evidence Fingerprints Blood Semen Saliva Urine

13 Fingerprints Fluorescent powders Lasers

14 Fingerprints Fluorescent Powders Natural or Synthetic Organic Derivatives Normal or Magnetic UV Light and Colored Filters Orange Powder + Orange Filter = Orange Print Advantages Disadvantages [6] [7]

15 Fingerprints - Lasers High Sensitivity Argon Laser Lens used lens Filters Photographs Advantages Disadvantages [8]

16 Fingerprints - Lasers [9] [9] 230 nm wavelength 280 nm wavelength [9] 300 nm wavelength

17 Blood Alternative Light Sources Luminol and BlueStar

18 Blood Alternative Light Sources Dry Blood = No Fluorescent Effect High absorption in broad region of light 300 nm to 900nm Strongest absorption band ( nm) [11] Appears as a dark spot Advantages Disadvantages [10]

19 Blood - Luminol Hemoglobin Complex multi-step process Dependent on many things

20 Blood - Luminol

21 Blood - Luminol Advantages Disadvantages [1]

22 Blood - BlueStar Same reaction as luminol Luminol vs. BlueStar Advantages Disadvantages [12] [13]

23 Bodily Fluids Semen, Urine and Saliva Alternative Light Sources

24 Semen Alternative Light Sources Dry Semen = Strong Photoluminescence Substance Emission Spectrum: nm Excitation Spectrum: nm Violet Light + Yellow Filter = Yellow Stain [11] Advantages Disadvantages [10]

25 Saliva Alternative Light Sources Colorless, difficult to detect Optimal Contrast on white cotton Violet Light + Orange Filter = White Thin Edged Stain Advantages [11] [10] Disadvantages

26 Urine Alternative Light Sources Hard to see due to nature of urine Diluted on fabric Fluorescent color varies [11] Violet Light + Orange Filter = White Stain Advantages Disadvantages [10]

27 References Akiba, N.; Kuroki, K.; Kurosawa, K.; Tsuchiya, K. Visualization of Aged Fingerprints with an Ultraviolet Laser. J. Forensic Sci. 2018, 63 (2), Akiba, N.; Saitoh, N.; Kuroki, K. Fluorescence Spectra and Images of Latent Fingerprints Excited with a Tunable Laser in the Ultraviolet Region. J. Forensic Sci. 2007, 52 (5), Barni, F.; Lewis, S.; Berti, A.; Miskelly, G.; Lago, G. Forensic Application of the Luminol Reaction as a Presumptive Test for Latent Blood Detection. Talanta. 2007, 72, Creer, K. Operational Experience in the Detection and Photography of Latent Fingerprints by Argon Ion Laser. Forensic Sci. Int. 1983, 23 (2-3), Creer, K. Some Applications of an Argon Ion Laser in Forensic Science. Forensic Sci. Int. 1982, 20 (2), Lee, W.; Khoo, B. Forensic Light Sources for Detection of Biological Evidences in Crime Scene Investigations: A Review. Malaysian Journal of Forensic Sciences. 2010, Vol 1, Menzel, E. Recent Advances in Photoluminescence Detection of Fingerprints. Sci. World J. 2001, 1, Quickenden, T.; Cooper, P. Increasing the Specificity of the Forensic Luminol Test for Blood. Luminescence 2001, 16, Skoog, D. A.; Holler, F. J.; Crouch, S. R. Principles of Instrumental Analysis, 6th ed.; Cengage Learning: Australia, Su, J. Seminal Stain Fluorescence Using Three Alternative Light Source-Barrier Filter Combinations on Six Different Colors of Cotton Fabrics. M.S. Thesis, Boston University School of Medicine, Valeur, B.; Berberan-Santos, M. Molecular Fluorescence; 2nd ed.; Wiley-VCH: Weinheim, Virkler, K.; Lednev, I. Analysis of Body Fluids for Forensic Purposes: From Laboratory Testing to Non-Destructive Rapid Confirmatory Identification at a Crime Scene. Forensic Sci. Int. 2009, 188, Wilson, R.; Akhavan-Tafti, H.; DeSilva, R.; Schaap, A. Comparison Between Acridan Ester, Luminol, and Ruthenium Chelate Electrochemiluminescence. Electroanalysis. 2001, 13, Webb, J.; Creamer, J.; Quickenden, T. A Comparison of the Presumptive Luminol Test for Blood with Four Non-Chemiluminescent Forensic Techniques. Luminescence. 2006, 21,

28 Picture References Skoog, D. A.; Holler, F. J.; Crouch, S. R. Principles of Instrumental Analysis, 6th ed.; Cengage Learning: Australia, Akiba, N.; Saitoh, N.; Kuroki, K. Journal of Forensic Sciences 2007, 52 (5), Miranda, G. E.; Prado, F. B.; Delwing, F.; Daruge, E. Analysis of the Fluorescence of Body Fluids on Different Surfaces and Times. Sci. Justice. 2014, 54 (6),

29 THANK YOU! Questions? [1]