Group 5 luminol & dna

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  • 1. Influence of the Luminol Chemiluminescence Reaction on the Confirmatory Tests for the Detection & Characterization of Bloodstains in Forensic Analysis Julio Abreu, William Chauvin, Conor McMenamin,John Vitale, Andrew Youngstrom BIOL 1115 Dr. Missy McElligot 16 February 2012

2. Introduction

    • Detection of crime scenes
      • Focus police work
    • Luminol
      • Detection of invisible blood stains
    • Evaluation of whether or not luminol negatively affects blood and DNA testing

3. Objectives

    • Verifyeffect luminol has on blood and DNA testing
    • Evaluate dependence on incubation time
    • Evaluate dependence on luminol concentration

4. Method of use in CSI

    • Luminol applied to a surface via spray bottle
      • Detects the presence of minor, unnoticed or hidden bloodstains
      • Diluted down to a level of 1:106 (1 L of blood in 1 L of solution)
    • Used to trace blood trails or splatters
    • Blood has distinct slow blue glow

5. Luminol Reaction

    • Luminol dissolved in a base to deprotonate nitrogens
    • Luminol reacts with an oxidizing agent
      • Removes N 2
      • Replaces the Nitrogen with Oxygen
    • Protons released in the form of blue light (photons) as the molecule falls to the ground state

6. Testing

    • Human gamma-globulinesin animmune-hematological assay
      • Gamma globulines protect against bacterial and viral infectious diseases
      • Assay measures activity of immune-related parts of blood
    • X and Ychromosomes quantified usingPlexor HY System
      • Plexor HY assay - DNA detection down to 6.4pg
      • Plexor HY System determines the concentration of total human DNA and male human DNA simultaneously
      • Tests for false-negative results that may occur

7. Methods: Investigation 1 8. Methods

  • Group 1:
    • 21 samples
    • 100 L of blood mixed with 200 L of luminol solution
    • Luminol concentrations of 0.50%, 2.50%, and 5.0% p/v
    • Samples incubated and measured at: 1, 4, 6, 8, 12, 24,48, 72 hours
    • Immune-hematological assays for gamma-globuline detection performed on the samples
    • DNA extraction from samples and quantified

9. Methods: Investigation 2 10. Methods

  • Group 2:
    • 21 samples
    • Serial dilution of DNA and luminol solution
    • 50 to 0.032 ng/L
    • Luminol concentrations of 0.50%, 2.50% and 5.0% p/v
    • Incubated for 8 months
    • Quantitated using real time PCR on a Bio-Rad IQ5 qPCR instrument

11. Figure 1. DNA quantitation of the Group 1 samples with luminol solutions at varying concentrations.

  • Figure 1
    • Group 1 - varied shorter incubation time
      • Incubation time and luminol concentration did not affect DNA concentration

Results 12. DNA amount after incubation of 4 L of DNA and4 L of luminol solution at varying concentrations by eight months.

  • Table 1
    • Group 2 - long constant incubation time for all samples
      • DNA amount after 8 month incubation
      • DNA can be detected even at low solution concentration levels

Results 13. Conclusion

    • Luminol impacts the identification of the blood splatter
      • Does not impact DNA identification
    • After long periods of incubation in the luminol solution, DNA concentration remains unaffected
      • Important because luminol should not affect or otherwise impact the identification of DNA profile

14. Significance to Biology

    • Biochemistry
      • Iron within hemoglobin of red blood cells acts as a catalyst for the luminol solution to begin a redox reaction
      • Reaction reduces the luminol and produces photons
        • Emits a blue glow
    • DNA
      • Autosomal DNA: all chromosomes that are unrelated to the X,Y sex chromosomes
      • Makes up genetic "fingerprint"

15. Article Citation

  • Santos, V.R.D., W.X. Paula, and E. Kalapothakis. "Influence of the
  • Luminol Chemiluminescence Reaction on the Confirmatory Tests for the Detection and Characterization of Bloodstains in Forensic Analysis."Forensic Science International(2009): 196-97. Web.

16. Influence of the Luminol Chemiluminescence Reaction on the Confirmatory Tests for the Detection & Characterization of Bloodstains in Forensic Analysis Julio Abreu, William Chauvin, Conor McMenamin,John Vitale, Andrew Youngstrom BIOL 1115 Dr. Missy McElligot 16 February 2012

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