The Degradation of DNA due to Washing and the Effectiveness of
Luminol in Finding Concealed Blood on These Carpets
Bailey Walker
Central Magnet School
Research Purpose
Materials and Methods
Conclusion
The purpose of this research is to deepen the understanding of
Luminol used to detect invisible blood on carpet and whether the
degradation of the DNA itself due to washing is a factor in how
effective the Luminol is. Also, the production of a base for
comparing blood stains at crime scenes that have been detected
using Luminol to the results found in this experiment. This is useful
to crime scene experts, so they can see if the blood stains have
been tampered with by washing using the results from this study.
The first step in completing this experiment was to obtain all materials, making sure to have personal protective equipment such as gloves, an
apron, and goggles. The pig’s blood, which was obtained from C & F Meats who slaughters healthy animals for the use of meat products, was kept
refrigerated until the day it was used. Before applying the blood to the carpet, it was allowed to reach room temperature to ensure that the
viscosity was similar to that of an actual alive being. The carpet was cut into squares much bigger than necessary to allow room for smearing (11
inches x 17 inches were used here) and labelled one through six (making sure to label it on the back so that the contents of the marker do not
interfere with the blood). Black plastic liner like the type used in a garden was placed on the floor. Next, cardboard was placed on top of the
black plastic liner. The cardboard was hopefully efficient in absorbing some of the blood that sept through the carpet and the liner was there just
in case the cardboard was not completely effective.
The blood was measured out using a dropper and a graduated cylinder.
5 mL of blood was dropped on each carpet in approximately the same
spot or pattern. The blood moved some due to uneven floors; however,
this was not concerning because it did not affect the project as a whole.
A smaller amount of blood was used to allow for plenty of room for cleaning because the stain would smear. The blood was allowed to sit for 24
hours to ensure that it had been completely absorbed. After the blood had had time to soak in, the cleaning process was started.
Each wash was comprised of 10 mL of cleaning solution, 45 seconds of scrubbing and the suction of the solution
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and stain reminisce. The cleaning solution consisted of 8oz of carpet cleaner and 40oz water. The carpet labelled
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number one was washed once using this process, carpet two was washed twice repeating each wash using the
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same process and so on through five. The sixth carpet was the control carpet and was not washed at all to
prevent any confounding variables that could arise from an ingredient in the soap used for cleaning the carpet. The control was also used to
confirm the efficacy of the Luminol and make sure that it worked correctly. After each carpet had been washed the desired number of times, the
Luminol was applied and allowed to develop.
Approximately 6 squirts of Luminol was applied on the spot to fully saturate it. Next, the carpet squares were
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studied in a dark room to compare each carpet and the effectiveness of Luminol after each wash. Finally, the r
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results were compared and recorded. The findings were scored based on visibility of the stain and brightness of
the Luminol.
This experiment proved to be successful in that the Luminol is much
less effective on carpet that has suffered DNA and fabric
degradation due to excessive washing. The adhesion of the DNA to
the carpet after several washes was weakened through damage or
disarmament. Thus, the Luminol cannot adhere properly to the
DNA. Luminol is often the first chemical agent used at crime scenes
to identify the presence of DNA. This information could be useful to
crime scene investigators and other forensic professions by telling
them whether the blood has been altered using chemicals found in
carpet cleaner or not. They can use the data collected in this
experiment to compare to the stains found at the scene and will be
able to tell if it has been altered and approximately how many
times it has been chemically altered through cleaning.
Introduction/Background
According to Filippo, Lewis, Berti, Miskelly, and Lago (2007), “Luminol
has been effectively employed for more than 40 years for the
presumptive detection of bloodstains which are hidden from the naked
eye at crime scenes.” This being said, Luminol is a very important
agent used in many criminal cases to determine if bodily fluid is
present, so a study to see how effective it is under the conditions in
this thesis are necessary. The topic of study is the effectiveness of
Luminol on carpet after multiple cleaning treatments. The washings
will tell us if Luminol is just as effective as if the carpet had been
washed once rather than the carpet being washed several times. This
research will also tell us how much the DNA is disarrayed and damaged
during each washing cycle. The intent of this research is to contribute
to forensics in many possible ways. Forensics is a growing field and
always open to new research. According to the all evidence collected,
Luminol should be less bright on the carpets that have heavy fabric
degradation due from washing.
The topic of study deals with blood stained carpet and the number of
times the carpet can be washed without losing the DNA in the blood.
The blood will be found with Luminol, which is an agent used to
detect blood that cannot be seen with the naked eye. As according to
Frascione, Thorogate, Daniel, and Jickells (2011), “Body fluids are
considered one of the most important evidence types in forensic
casework. The presence and location of blood, semen and saliva can
provide crucial information to investigator” (p. 508512). Sweet, A.
Lorente, M. Lorente, Valenzuela, and Villanueva believe that (as cited
by Frascione et al., 2011, p.508512), “Blood is probably the most
common body fluid present at the scene of a crime.” This evidence
strengthens the reasoning behind the choice to study blood. This
research could help fill some void in the area of bloodstain analysis
with the use of Luminol and could prove very important. According to
Filippo, Lewis, Berti, Miskelly, and Lago (2007), “Luminol has been
effectively employed for more than 40 years for the presumptive
detection of bloodstains which are hidden from the naked eye at
crime scenes and, for this reason, has been considered one of the
most important and well-known assays in the field of forensic
sciences.” For that reason, this study could be of great use to Forensic
Investigators. “Crime scene personnel…choose this test [Luminol] as
the preferred field blood test at all crime scenes,”(Grispino, 1990) for
the discovery of invisible blood. Since Luminol is often the first agent
used at a crime scene, it is crucial that carpet at several different
stages be studied. As said by Stene (2012), “The most destructive of
these acts is the deliberate cleaning of bloodstains with chemical
agents such as bleach.” In this project, the carpets will be cleaned
with chemicals because it is harmful to the DNA. The intention is to
see if the Luminol can find and attach to the DNA on the excessively
washed carpets. According to Carr, Kemp, Kieser, Niven, and Taylor
(2009), “The structural stabilization and degradation of fabric due to
laundering significantly alters fabric properties, yet the effect of such
on severance morphology does not appear to have been investigated”
(p. 86+). The test using the Luminol will check to see how effective
Luminol is even after the use of chemicals on the stain and the
degradation of the fabric of the carpet itself after many washes. As
stated previously, this type of fabric degradation has not been
investigated thoroughly. Through this project, the fabric degradation
of the carpet will be observed with the use of Luminol, which should
tell us how much of the original bloodstain is there and if any of the
stain was lost during the washing process. The condition of the carpet
can also change the way the DNA is attracted to the fabric, therefore
causing complications with the attraction between the Luminol and
the blood in the carpet. This is a new study to be performed.
RESEARCH POSTER PRESENTATION DESIGN © 2011
www.PosterPresentations.com
Results
After obtaining all materials, performing the experiment, and collecting the data, an analysis of the carpet in a dark room was performed to rate
the brightness and clarity of the chemiluminescence caused by the Luminol attaching to the DNA. The carpet were scored: 1-not bright or visible,
2-less bright but clear, 3-visible but not bright, 4-bright and clear, and 5-very bright and clear.
References
Carr, D. J., Kemp, S. E., Keiser, J., Niven, B. E., & Taylor, M. C.
(2009). Forensic evidence in apparel fabrics due to stab events.
Retrieved from http://www.wcmt.org.uk/reports/1004_1.pdf
Frascione, N., Thorogate, R., Daniel, B., & Jickells, S. (2012).
Detection and identification of body fluid stains using antibody
nanoparticle conjugates. Retrieved from
https://kclpure.kcl.ac.uk/portal/en/publications/detection-andidentification-of-body-fluid-stains-using-antibodynanoparticleconjugates(edfee9f9-0640-4cd6-b4e1-837b99dbfadc)/export.html
Filippo, B., Lewis, S. W., Berti, A., Miskelly, G. M., & Lago, G.
(2007). Forensic application of the luminol reaction as a
presumptive test for latent blood detection. Retrieved from
ScienceDirect:
http://www.sciencedirect.com/science/article/pii/S003991400700
0082
Grispino, R. R. (1990). Effect of Luminol on the Serological Analysis
of Dried Human Bloodstains. Retrieved from
http://www.bioforensics.com/conference04/Serology/Dilute_Bloo
dstains.
pdf
Stene I, Adair T. The Survival of Neat and Cleaned Blood after the
Application of Wallpaper. Retrieved from http://www.acsr.org/wpcontent/uploads/2012/08/Stene-Adair-RS.pdf
Acknowledgements
Carpet #1 scored a 4.5 out of
5 on brightness and clarity.
Carpet #2 scored a 4 out of 5
on brightness and clarity.
Carpet #3 scored a 3 out
of 5 on brightness and
clarity.
Carpet #4 scored a 2 out of 5
on brightness and clarity.
Carpet #5 scored a 1.5 out
of 5 on brightness and
clarity.
Carpet #6 scored a 5 out
of 5 on brightness and
clarity.
DISCUSSION
The results obtained in this experiment are exactly what was hoped to be achieved. This experiment was meant to prove that Luminol is less
effective on carpet that has been washed multiple times. In scoring each carpet on brightness and clarity, the scores corresponded well to each
carpet. The carpets washed several times received lower scores because the Luminol couldn’t find as much DNA to make the stain appear as bright
or clear on those carpets. The carpets that were washed less received scores much higher because they were brighter and much closer in
brightness and clarity to that of carpet #6 (the control).
According to Carr, Kemp, Kieser, Niven, and Taylor (2009), “The structural stabilization and degradation of fabric due to laundering significantly
alters fabric properties, yet the effect of such on severance morphology does not appear to have been investigated” (p. 86+). It appears as if the
carpets had some degradation from excessive washing, and the use of harmful chemicals on the carpets also damaged and disarrayed some of the
DNA causing the Luminol to be less effective in finding it.
A possible confounding variable could be the absorbance rate of the blood into the carpet, because some of the carpet squares could absorbed
the blood much more quickly than others. This could be due to the fact that the carpet was rolled up and some became compressed from being on
the underside of the roll and withstanding the weight of the carpet. However, this should not have overall affected the experiment too much,
because there was not padding under the carpet for the blood to soak completely through. To prevent this type of compression, the carpet should
be laid out flat instead of rolled. An experiment for further study into this topic would be to use different types of carpet such as Shag or Berber.
Also an additional variation is to use more blood and attempt to use human blood to see if the DNA is harder or easier for the Luminol to adhere to
I would like to say thanks to:
•Chris Warren for allowing me to use First Cumberland Presbyterian
Church as a lab
•Pam Stewart for allowing me to borrow lab supplies and also
advising and helping with my project.
•Mike Patrick for providing carpet for the experiment.
•Lynne Maxwell for helping me to format and construct the paper,
•Delia Topping-Boost for advising and encouraging me to stay on
schedule.
•Also a special thanks to Tiffany Saul for helping me with her
expertise and knowledge on this topic and overall helping to guide
my thoughts during this process.