Determination of Thujone in Absinth-type Liqueurs

~ By John B. Wilson ~

Published in Association of Official Agricultural Chemists, Vol 19, 1936

An important early paper that clearly demonstrated the weaknesses of the then current method for deterimining thujone level in absinthe.


The Gross and Smith colorimetric method for the determination of rotenone and deguelin has been improved. Sulfuric acid has been substituted for nitric acid, the concentration of the alcoholic potassium hydroxide has been reduced by diluting with water, and the nitrite necessary to produce the color is added as sodium nitrite in the alcoholic potassium hydroxide. The stability, hue, and depth of color produced by the rotenone as well as that produced by the reagents themselves can be easily controlled, This combination of reagents practically eliminates fading and increases the sensitivity of the test 20 times.


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