KM Blood Phenolphthalein Test

Description

KM Blood Phenolphthalein Test

Test for the presence of blood on materials using phenolphthalein. The test will not distinguish between animal and human blood. Further serology tests are needed. Kit contains instructions, blood standard and reagents to complete 30 tests.

Aligned to the Next Generation Science Standards (NGSS)*

Disciplinary Core Ideas: PS1.A; PS1.B
Performance Expectations: MS-PS1-2
Cross Cutting Concepts: Patterns
Engineering Practices: Analyzing and Interpreting Data

Kit Includes:
2 x 25mL Phenolphthalein, 2% Solution
2 x 25mL Ethyl Alcohol
1 x 50mL Hydrogen Peroxide, 3% Solution
5 Blood Standard Strips
50 Cotton Swabs

Notes:

Phenolphthalein is a widely used chemical compound known for its application in various fields, including forensic science. In blood presumptive testing, phenolphthalein plays a crucial role in detecting the presence of blood through a colour reaction. The 3-part phenolphthalein blood presumptive test is an advanced version that offers several advantages over the traditional 2-part test, primarily due to its longer shelf life, making it a more cost-effective and efficient solution for forensic investigations.

 

Part 1: Understanding the Phenolphthalein Blood Presumptive Test The phenolphthalein blood presumptive test is a common method used by forensic experts to detect the presence of blood at a crime scene. This test relies on the chemical reaction between phenolphthalein and the heme group found in hemoglobin, a protein present in blood. When phenolphthalein comes into contact with blood, it produces a characteristic pink coloration, indicating the presence of blood.

 

In the 2-part version of the test, phenolphthalein is typically mixed with hydrogen peroxide to trigger the colour reaction. However, this formulation has a limited shelf life, requiring frequent replacement of the reagents to ensure accurate results. Moreover, the stability of the reagents may be compromised over time, leading to false negatives or inconclusive results.

 

Part 2: Advantages of the 3-Part Phenolphthalein Blood Presumptive Test The 3-part phenolphthalein blood presumptive test offers significant improvements over its 2-part counterpart, primarily due to the inclusion of an additional stabilizing agent in the formulation. By incorporating a third component that enhances the stability of the reagents, the 3-part test has a longer shelf life, ensuring the reliability and accuracy of the results over an extended period.

 

The enhanced stability of the 3-part test minimizes the need for frequent reagent replacement, reducing operational costs and resource requirements for forensic laboratories. Furthermore, the longer shelf life of the test kit enables forensic investigators to maintain a ready supply of reliable reagents, streamlining the testing process and expediting case resolutions.