Fluorometric determination of malonic acid with dicyclohexylcarbodiimide.

By using dicyclohexylcarbodiimide (DCC) as a reagent, a fluorometric method for the determination of malonic acid has been developed. The reagent combined with the acid to afford N,N-dicyclohexylbarbituric acid which reacted with glutaconic aldehyde, generated from the reaction of DCC with pyridine, to form a fluorophore. The fluorophore was then determined at lambda ex = 469 nm and lambda em = 562 nm. The calibration curve was linear from 2.5 to 25 nmol. The relative standard deviation obtained with 10 nmol of malonic acid was 5.77% (n = 10). The specificity is also discussed.