12.11.2012 Views

Examination of Firearms Review: 2007 to 2010 - Interpol

Examination of Firearms Review: 2007 to 2010 - Interpol

Examination of Firearms Review: 2007 to 2010 - Interpol

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Table 1. Composition <strong>of</strong> body fluids (by Virkler and Lednev 2 )<br />

Blood Semen<br />

-Acid<br />

Saliva Vaginal fluid Urine Sweat<br />

-Hemoglobin phosphatase<br />

-Prostate-specific<br />

-Amylase -Acid phosphatase -Urea -Urea<br />

-Fibrinogen antigen -Lysozyme -Lactic acid -Creatinine -Lactic acid<br />

-Erythrocytes -Sperma<strong>to</strong>zoa -Mucin<br />

-Buccal epithelial<br />

-Citric acid -Uric acid -Chloride<br />

-Albumin -Choline<br />

cells -Urea -Chlorine<br />

-Tamm-<br />

Horsfall<br />

-Sodium<br />

-Glucose -Spermine -Thiocyanate -Vaginal peptidase glycoprotein -Potassium<br />

-Glycogenated<br />

-<br />

-Immunoglobulins -Semenogelin -Potassium epithelial cells<br />

Immunoglobulins<br />

3.2 Blood<br />

-Zinc -Bicarbonate -Acetic acid<br />

-Citric acid -Phosphorus -Pyridine<br />

-Lactic acid -Glucose<br />

-<br />

-Squalene<br />

-Fruc<strong>to</strong>se Immunoglobulins -Immunoglobulins<br />

-Urea<br />

-Ascorbic acid<br />

-Immunoglobulins<br />

3.2.1 Current confirma<strong>to</strong>ry techniques<br />

In <strong>to</strong>day's forensic practice potential bloodstains that have been discovered at the<br />

scene <strong>of</strong> the crime are in first instance screened with presumptive tests like the<br />

Kastle-Meyer (KM). This presumptive blood tests meets practically all requirements<br />

that a diagnostic test should have: sensitive, high specificity, quick, simple, and safe.<br />

The tests that can be subsequently used for the confirma<strong>to</strong>ry identification <strong>of</strong> blood<br />

are amongst others: the microscope test, spectroscopic tests, and immunological<br />

tests 2 .<br />

The microscope test involves the counting <strong>of</strong> visualized blood cells, this can be<br />

expanded by the use <strong>of</strong> a scanning electron microscope (SEM) which is able <strong>to</strong> show<br />

the morphology <strong>of</strong> the cells present in the stain. An energy dispersive X-ray (EDX)<br />

can also be used <strong>to</strong> show the elemental composition <strong>of</strong> the stain.<br />

Spectroscopic tests, such as UV-vis(ible) absorption, determine if haemoglobin and<br />

its derivatives are present in the stain, which can confirm the presence <strong>of</strong> blood in a<br />

stain 2 . Spectroscopic tests can yield a positive result when blood is present in very<br />

dilute amounts. Nevertheless this technique also has its limitations and<br />

disadvantages, for example results can be interfered by: the exposure <strong>to</strong> sunlight,<br />

heating, and rust.<br />

A disadvantage <strong>of</strong> both tests mentioned above is the lack <strong>of</strong> species specificity. A<br />

positive result means that we are dealing with blood, which can be from a human<br />

being but also from any other animals. To show if the blood in a stain is human For<br />

example the Rapid Stain Identification test (RSID) can be used. The test is specific<br />


 327


Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!