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Dr. Fatima Amjad, Dr. Iqra Naheed, Dr. Sumaira Naeem

ABSTRACT-Blood is one of the principal sources of evidence in crime scene investigations. The level of hemoglobin in human blood is known to hardly fluctuate over time in a healthy adult patient. Using a method like the sodium lauryl sulfate (SLS) method for hemoglobin level determination is beneficial because SLS converts any other derivates of hemoglobin into methemoglobin. The amount of hemoglobin would be determined using the linear correlation between the absorbance of methemoglobin and its amount in blood samples. Those curves differ significantly from sample to sample. Therefore, a differentiation can be observed between the blood samples of different originators. Ultraviolet-Visible spectrophotometry and an image processing software were utilized to quantify the amount of hemoglobin in different human whole blood samples. The data obtained was used to plot different graphs, each one representing an individual. A distinction between a fresh blood sample and an aged blood sample is determined using enzyme-linked immunosorbent assay (ELISA) by tracking the change in absorbance of horseradish peroxidase (HRP) present in blood serum. Based on the results obtained, a clear difference in change of absorbance between a fresh and one-week old blood serum is observed. Future development and further analysis may lead to the conception of a small device using the method of quantification of hemoglobin proposed in this project, with which forensic investigators would be able to use directly on-site and get an idea of how many people where on a crime scene.

hemoglobin, human blood, Ultraviolet Visible spectrophotometry, image processing softwar