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The Chemiluminescent imaging of blood on washed cotton and polyester fabrics
Duwaraga Manoharan
Keywords :
Luminol ; cotton swatch ; polyester swatch ; blood
The Chemiluminescent imaging of blood on washed cotton and polyester fabrics
Abstract
Luminol is a sensitive test used by forensic investigators to detect blood over a large area in crime scenes . When in contact with blood , luminol emits a bright blue light .
This reaction , known as chemiluminescence , was utilised in this study to test luminol sensitivity on 60 , 100 % cotton and 60 , 100 % polyester swatches measuring 10cm by 10cm . All samples were washed once , twice or thrice with non-biological or biological laundry capsules , air-dried and subsequently sprayed with luminol and photographed in a dark room .
Blood was detected on all 60 blood-stained swatches regardless of washing patterns or laundry capsules . The 60 unstained controls produced little or no chemiluminescence thus making luminol a sensitive and useful test for detecting blood on fabrics found in crime scenes .
DOI :
Introduction
Blood is common form of evidence found in crime scenes ( Tobe , Watson and Daéid , 2007 ) and is easy to visualise under the naked eye due to its distinct red colour that indicates the presence of the red pigment haemoglobin ( Mader and Windelspecht , 2016 ). This red colour provides a contrast between the blood and the background , but on dark or washed surfaces , it can be difficult to see ( Butler , Chaseling and Wright , 2019 ). This important biological fluid is composed of two components - plasma and formed cellular components . These formed cellular components consist of erythrocytes ( red blood cells ), leukocytes ( white blood cells ) and platelets . Platelets are suspended in plasma and carry out important processes such as defence against foreign pathogens , transport of oxygen and carbon dioxide in the body and blood clotting ( Bell , 2019 ). The discovery of blood in crime scenes has huge importance as leukocytes contain vital DNA sources in their nuclei ( Bell , 2019 ) that provide important clues about the victims and suspects involved in the crime scenes .
However , if bloodstains have been diluted by planned and meticulous washing , detection can be limited . In this case , a solution called luminol is used to find blood . Luminol utilises haemoglobin in the blood to indicate the presence of blood in
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