Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Hacettepe University, Fen Bilimleri Enstitüsü, Biyomühendislik A.B.D., Turkey
Approval Date: 2022
Thesis Language: Turkish
Student: ILGIN DENİZ GÜNGÖR
Principal Supervisor (For Co-Supervisor Theses): Necdet Sağlam
Co-Supervisor: Ramazan Akçan
Abstract:
Bloodstains are abundant biological fluids that are encountered in crime scenes. Precise
bloodstain detection on the “proof” has vitally importance for ongoing or post-commital
stages. The criminal inclined to dispose the proofs that has an effect of inadequate amount
of bloodstains. In case of loss in stain characteristic, the required presumptive or
correlative tests can not identify the located stain with high accuracy. Twelve equal sized
white %100 cotton fabrics were prepared to washing with six different cleansing solutions
after creating bloodstains. The aim of the study is examining the treatment effect of each
cleansing solutions for bloodstains with Raman spectroscopy. Distilled water and distilled
water solutions of methanol, HCl, soap, detergent and hypochloride were used as
cleansing liquids. Solutions were grouped as five sets by observing the effect of fresh
solution and temperature differences as 20oC, 30oC and 60oC. Raman spectrums were
collected with 785 nm laser source after all washed fabrics has been turning into dry state.
For chemometrics, Raman sepctrums of different treated fabrics with bloodstains and
iv
clean fabrics were classified with PLS-DA method. MATLAB PLS_Toolbox was used
for both analysis and dividing the spectrums into train and test data. The chemometric
model was built with the classification parameters as sensitivity, selectivity and
efficiency. Selectivity was reached to 100% for all cleansing solutions and washed fabric
with bloodstains. The classificaiton has been made for distilled water with 90% sensitivity
and %94.9 efficiency; for methanol solution with 96% sensitivity and 97.7% efficiency
and with HCl soluiton with 91.7% sensitivity and 95.7% efficiency was calculated.
Likewise, classification for soap solution 85.0% sensitivity and 92.2% efficiency; for
detergent solution 100% sensitivity and 100% efficiency and lastly, for hypochloride
solution 90% sensitivity and 95.11% efficiency was reached. Discrimination of different
solutions and washed bloodstains on fabric was achieved with 92.7% sensitivity, 100%
selectivity and 95.7% efficiency.