Serology and DNA Free Essay

Blood Structure Analysis

As a rule, almost every genotypic examination begins with the determination of the presence of biological material on the carrier object, submitted for examination. Modern science has developed many primary and evidence-based methods for identifying blood, saliva, sperm, urine, and other tissues and body fluids. The fluid chosen for discussion is blood.

There are two groups of blood detection methods: preliminary, which only suggest the presence of blood in the object and are used mainly during the inspection of the scene of the incident, and evidentiary, which confirm the presence of blood on the carrier. According to Li et al (2011), evidence-based methods for the origin of bloodstains are based on the detection of hemoglobin and its derivatives, as well as substances characteristic only of blood. For instance, the spectral method is based on the ability of hemoglobin and its derivatives (methemoglobin, carboxyhemoglobin, hematoporphyrin) to absorb light waves of a certain length and form characteristic absorption spectra. According to Karger et al (2008), detection of the hemoglobin spectrum proves the presence of blood in the test object. There is also microspectral method (establishing blood in a microquantity of a substance) and emission spectral analysis (used in case of deep blood destruction, for example, during charring or rotting).

In addition, it can be said that the thin-layer chromatography method allows to obtain a positive result even in cases where conventional methods of determining the presence of blood are ineffective. The principle of the method lies in the fact that the solvent (ammonia solution and butanol), passing through samples cut from the objects of study and fixed on chromatographic paper, decomposes the blood into components, which then should be manifested properly. After carrying out certain procedures, a change in the color of the pigment site proves the blood origin of the spot. To identify blood in contaminated and old stains, as well as bloodstains on tissues subjected to washing, the method of direct radial microchromatography on paper is used.

Thus, modern science and practice have developed many methods for detecting biological fluids on objects – carriers. In order to properly conduct such a research, it is necessary not only to have special knowledge in various fields of science: forensic science, the criminal process, physics, chemistry, biology and other sciences, but also be able to competently apply them in practice.

References

Li, B., et al. (2011). “The estimation of the age of a blood stain using reflectance spectroscopy with a microspectrophotometer, spectral pre-processing and linear discriminant analysis.” Forensic Sci Int., 212 (1-3).

Karger, B., et al. (2008). “Bloodstain pattern analysis–casework experience.” Forensic Sci Int., 181 (1-3).

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"The terms offer and acceptance." freeessays.club, 17 May 2016

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"The terms offer and acceptance." freeessays.club, 17 May 2016

[Accessed: June 1, 2020]

"The terms offer and acceptance." freeessays.club, 17 May 2016

[Accessed: June 1, 2020]

"The terms offer and acceptance." freeessays.club, 17 May 2016

[Accessed: June 1, 2020]