Determination of ketone bodies in blood and urine by means of vanillin in alkaline medium.

& A PREVIOUS COMMUNICATION (1) we have reported that vanillin reacts with a large number of organic compounds with a carbonyl group, with aldehydes, and particularly with ketones, diketones, and ketonic acids to produce yellowish, or yellowish-red color complexes. Because of its wide reactivity the vanillin-alkali reagent cannot be used for any specific carbonyl compound unless it is first separated by extraction with solvents, by precipitation, by chromatography, by electrophoresis, or by distillation or aeration especially if the compound has a low boiling point. Acetone has a low boiling point, 56.5#{176}. It can therefore be separated easily by aeration or distillation from other compounds in a biologic fluid or solid tissue. Acetoacetic acid may also be determined, for upon treatment with acid it is readily converted to acetone. The ketogenic acid, fl-hydroxybutyric acid, also yields acetoacetic acid on oxidation. We have developed a method for acetone based upon its separation from blood and urine by distillation and subsequent treatment of the distifiate with a vanilhin-alkali reagent. This method offers many advantages over the very widely used procedure of Behre and Benedict (2) in which salicylaldehyde in alkaline medium is utilized as the reagent. Salicylaldehyde or 2-hydroxybenzaldehyde is a compound similar in chemical reactivity to vanillin or 3-methoxy-4-hydroxybenzaldehyde. The formation of a reddish-colored complex, the sodium salt of