What indicator is used in the Kastle-Meyer test?
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin.
How does the Kastle-Meyer test?
The 3-stage Kastle–Meyer (KM) test has been used for decades as a rapid, presumptive test for blood. The test identifies the heme component of hemoglobin, which in the presence of hydrogen peroxide catalyzes the oxidation of the indicator phenolophthalin, turning it pink [1], [2].
How do you use Kastle-Meyer reagent?
Kastle–Meyer reagent contains reduced phenolphthalein indicator in a basic solution. Simply wipe a presumptive bloodstain with a cotton swab, add a drop of the reagent, and then apply a drop of hydrogen peroxide. If the swab turns pink rapidly, it is positive for blood!
What color will the Kastle-Meyer blood test produce?
pink colour
Kastle-Meyer Colour test This will react with hydrogen peroxide in the presence of haemoglobin to produce a pink colour.
When should the Kastle-Meyer test be used?
Test Sensitivity and Limitations The Kastle-Meyer blood test is an extremely sensitive test, capable of detecting blood dilutions as low as 1:107. If the test result is negative, it is reasonable proof that heme (an ingredient in all blood) is absent in the sample.
How was the phenolphthalein test or Kastle-Meyer test done what type of result does it give?
Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color. While bloodstains normally appear red-brown in color, the color of the substrate or the age of a stain may affect the appearance or visibility of the stain.
How do you make a Kastle-Meyer reagent?
Procedure
- In a test tube, dissolve 0.1 g phenolphthalein in 10.0 ml of 25% sodium hydroxide solution.
- Add 0.1 g mossy zinc to the tube.
- Add a boiling chip and gently boil the solution until it changes color to become colorless or pale yellow.
- Allow the solution to cool.
When was the Kastle-Meyer test first used?
1903
The Kastle-Meyer test is a forensic presumptive blood test first developed in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin.
What is Meyer reagent?
Mayer’s reagent is an alkaloidal precipitating reagent used for the detection of alkaloids in natural products. Mayer’s reagent is freshly prepared by dissolving a mixture of mercuric chloride (1.36 g) and of potassium iodide (5.00 g) in water (100.0 ml).
What is the Kastle-Meyer reagent?
Description: Kastle-Meyer Reagent is 2% phenolphthalein in 20% potassium hydroxide solution; use with hydrogen peroxide for presumptive blood tests. Notes: This product is corrosive; separate acids from bases; separate oxidiser acids from organic acids.
How does LMG test work?
The leucomalachite green presumptive test for blood is a catalytic test which is based on the peroxidase-like activity of hemoglobin. Hemoglobin has the ability to cleave oxygen molecules from H2O2 and catalyze the reaction from the reduced form of leucomalachite green to the oxidized blue-green colored product.
What is the Kastle-Meyer test and how does it work?
The Kastle-Meyer test relies on the iron in hemoglobin, which is the iron-containing portion of a red blood cell, to promote the oxidation of phenolphthalin to phenolphthalein. Phenolphthalin is colorless, but in the presence of blood and hydrogen peroxide, it changes to phenolphthalein, which makes the solution pink.