Presumptive Tests for Blood (Exam 1) Flashcards
What does the phenolphthalein test rely on to cause a color change?
The peroxidase-like activity of blood
Phenolphthalein is a { } indicator.
pH
What color is phenolphthalein under acidic conditions?
Colorless
What color is phenolphthalein under alkaline conditions?
Pink
Define peroxidase.
Enzyme that catalyzes the peroxide-mediated oxidation of organic compounds
Define hemoglobin.
Protein said to exhibit peroxidase activity
If there is no hemoglobin present, then there will be { } color change.
No
What is the oxygen donor in a general peroxidase reaction?
Hydrogen peroxide
What color is oxidized K-M reagent?
Pink
What color is the reduced K-M reagent?
Colorless
What does the preparation step of the phenolphthalein involve?
Reducing the phenolphthalein into the Kastle-Meyer product
What does the lab step of the phenolphthalein involve?
Checking to see if the Kastle-Meyer reagent oxidizes
What are the 4 major reagents used in the phenolphthalein test?
1) Phenolphthalein
2) Water
3) NaOH
4) Zn
The Kastle-Meyer color test is another name for the…
Phenolphthalein test
What is the key principle behind the phenolphthalein test?
Blood in presence of an oxygen donor can catalyze an organic compound to change color
