Direct Determination Method of Phthalic Acid Esters in Vodka by HPLC

A method for the direct determination of phthalic acid esters (PAE), which include dibutyl phthalate (DBP), diheptyl phthalate (DHP) and di-2-ethylhexyl phthalate (DEHP), in vodka by high performance liquid chromatography was developed.A 100μl sample was directly injected into the chromatographic system without extraction or clean-up. A linear calibration plot for DBP, DHP and DEHP was obtained between 0.02ppm and 5.0ppm. The limits of detection were 0.005ppm for DBP, and 0.01ppm for DHP and DEHP. Fourteen samples of commercial vodka were analyzed by the proposed method. DBP was detected in seven samples in the range of 0.05 to 0.25ppm, and six of these samples contained DEHP in the range of 0.01 to 0.02ppm. The contents of DBP detected by the proposed method were confirmed by the GC method.During this investigation, we found that the amounts of PAE contaminating the filter paper and deionized distilled water were higher than those in vodka.