Asked by: Oktay Dole
science chemistry

What chemicals are used in the Kastle Meyer test?

Last Updated: 20th February, 2020

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.

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Also to know is, what is the Kastle Meyer test used for?

The KastleMeyer 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.

Similarly, what substances can cause a false positive Kastle Meyer test result? This test has some limitations. Namely, the enzymes in some vegetables (especially tomato, potato, cucumber, horseradish) can cause a false positive test result. Other non-blood substances which give positive results are: some fruit extracts, some metallic substances, or any other peroxidase-like substances.

Beside this, what is Kastle Meyer reagent?

KastleMeyer 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!

How does phenolphthalein detect blood?

Phenolphthalein (Blood) Phenolphthalein is a presumptive test that reacts with the heme molecule present in blood. A positive reaction gives a pink color. While a positive phenolphthalein reaction is indicative of blood, it is only a presumptive test and false positives are possible.

Related Question Answers

Basma Tejero

Professional

What do you see in a positive Kastle Meyer test?

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.

Olene Kaltschmid

Professional

What is the precipitin test?

Medical Definition of precipitin test
: a serological test using a precipitin reaction to detect the presence of a specific antigen specifically : a test used in criminology for determining the human or other source of a bloodstain.

Ranee Papageorge

Professional

What is meant by a presumptive test?

A presumptive test is a qualitative analysis that allows to identify, or confirm, the presence of a substance in a sample. These determinations usually occur, after a chemical reaction, and a specific colour is produced.

Khizar Boeckers

Explainer

How do you test a stain to see if it is blood?

With a spray bottle, saturate the area or item believed to be contaminated with blood with “fresh” hydrogen peroxide. If blood is present in a spill, it fizzes. Some people use this hydrogen peroxide on dried stains or residue as well. If there is blood present in the residue, it may not fizz if it is old.

Akila Orszulok

Explainer

Is Luminol a presumptive test?

Luminol (Blood) The search for the presence of blood at a crime scene is normally done by close visual examination. Because the reaction is not specific to blood, a follow up presumptive test, such as phenolphthalein, is typically run on potential samples prior to collection.

Harriet Narmada

Pundit

How do you make luminol spray?

How To Do It
  1. Add ½ teaspoon of Luminol to a plastic cup, and then add 2 tablespoons of water.
  2. Add ½ teaspoon of the perborate mixture OR hydrogen peroxide.
  3. Add a few crystals of copper sulfate (unless you purchased the “Blue Luminol,” which has the copper sulfate added).

Solveig Tjeerdstra

Pundit

What is the difference between a presumptive test and a confirmatory test?

Presumptive tests are less precise and indicate that an illegal substance may be present. Confirmatory tests provide a positive identification of the substance in question. This is called qualitative analysis, and determines what substances are present and if one of more of those substances is illegal.

Aura Piterskih

Pundit

What is phenolphthalein used for?

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

Xiaohui Medinilla

Pundit

What is the luminol test?

Luminol is a white-to-pale-yellow crystalline solid that is soluble in most polar organic solvents, but insoluble in water. Forensic investigators use luminol to detect trace amounts of blood at crime scenes, as it reacts with the iron in hemoglobin.

Genna Paradiso

Teacher

What are some types of presumptive blood test?

Luminol, leuchomalachite green, phenolphthalein, Hemastix, Hemident, and Bluestar are all used as presumptive tests for blood. In this study, the tests were subjected to dilute blood (from 1:10,000 to 1:10,000,000), many common household substance, and chemicals.

Clarisse Uppuluri

Teacher

How do presumptive blood tests work?

Presumptive tests react with the hemoglobin of all blood (human and animal) to catalyze the oxidation of a chromogenic compound, which produces a color change [25]. A positive reaction will result in the identification of the sample as possibly blood but not necessarily human blood.

Garth Eysen

Teacher

How can I test my blood at home?

In at-home blood typing tests, they typically ask that you prick your finger with a lancet and put drops of your blood on a special card. After putting the blood on the card, you can observe the areas where blood clumps or spreads out, and then match those reactions to an included guide.

Leann Matzchen

Reviewer

Which of the presumptive blood tests is considered the most sensitive?

The findings of this study indicate that the phenol- phthalein and the leucomalachite green tests are the most specific and that the tetramethyl- benzidine and orthotolidine tests are the most sensitive of the group.

Airon Smitten

Reviewer

What is the Teichmann test?

Teichmann test (haematin test)
A confirmatory test for blood based on the formation of distinctive haematin crystals that are viewed under a microscope. The reagents typically used are sodium chloride and glacial acetic acid.

Ginny Gim

Reviewer

How do you know if blood is dry?

Finding and documenting blood residue
Freshly dried bloodstains are a glossy reddish-brown in color. Under the influence of sunlight, the weather or removal attempts, the color eventually disappears and the stain turns gray. The surface on which it is found may also influence the stain's color.

Bouziane EspiƱeira

Reviewer

How does Leucomalachite green test work?

Leuco-malachite green (LMG) is used as a detection method for latent blood in forensic science. Hemoglobin catalyzes the reaction between LMG and hydrogen peroxide, converting the colorless LMG into malachite green. Therefore, the appearance of a green color indicates the presence of blood.

Stivan Tcharkin

Supporter

When was luminol first used at crime scenes?

In 1934, Huntress called this compound LUMINOL which means producer of light. The first proposed forensic use of luminol as a preliminary blood test was reported by Specht in 1937.

Erian Henkin

Supporter

Is phenolphthalein a base or acid?

Phenolphthalein is an indicator of acids (colorless) and bases (pink). Sodium hydroxide is a base, and it was in the pitcher at the beginning, so when added to the phenolphthalein in beakers 2 and 4, it turned pink (top half of the graphic).