HPLC–DAD analysis of ketones as their 2,4-dinitrophenylhydrazones in Brazilian sugar-cane spirits and rum

Using high-performance liquid chromatography (HPLC) and 2,4-dinitrophenylhydrazine as a derivatizing reagent, an analytical method has been developed for the analysis of ketones in hydro-alcoholic matrices, colored or not. The determination is carried out at 365 nm using a UV–Vis diode-array detector (DAD). For the ketones as their 2,4-dinitrophenylhydrazones, a good separation was achieved with a Supelco C18 column (25 cm×4.6 mm×5 μm) using a (methanol/acetonitrile)-water elution gradient. The methodology is simple, rapid, exhibits good reproducibility, and allows the analysis of both ketones and aldehydes in the same run. The application of this method to 34 sugar-cane spirits and 13 rums allowed the identification and quantification of acetone, acetophenone, cyclopentanone and 2,3-butanedione, at detection limits of 10 μg/l (2,3-butanedione) to 20 μg/l (cyclopentanone).