How to Make Kastle-Meyer Solution

The Kastle-Meyer test is a simple, reliable and inexpensive test to detect blood. Here is how to prepare the Kastle-Meyer solution used for the forensic test.

Kastle-Meyer Solution Materials

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How Does the Kastle-Meyer Test Detect Blood?

By Anne Marie Helmenstine, Ph.D.

• 0.1 g phenolphthalein powder
• 25% w/v sodium hydroxide solution (aqueous)
• 0.1 g mossy zinc
• distilled water
• 70% ethanol

Procedure

1. In a test tube, dissolve 0.1 g phenolphthalein in 10.0 ml of 25% sodium hydroxide solution.
2. Add 0.1 g mossy zinc to the tube. The solution should be bright pink.
3. Add a boiling chip and gently boil the solution until it changes color to become colorless or pale yellow. Add water, as necessary, to maintain the volume during boiling.
4. Allow the solution to cool. Decant the liquid and dilute it to 100 ml with 70 ethanol. This is the Kastle-Meyer solution.
5. Store the solution in a tightly-capped blue or brown bottle.

Sources

• Meyers, Thomas C. (2006). "Chapter 21: Serology". In Wecht, Cyril H.; Rago, John T. (eds.). Forensic Science and Law: Investigative Applications in Criminal, Civil, and Family Justice. Boca Raton, FL: CRC Press. pp. 410–412. ISBN 0-8493-1970-6.
• Remsen, Ira; Rouiller, Charles August (eds.) "Phenolphthalin as a reagent for the oxidizing ferments". American Chemical Journal. 26 (6) : 526–539.