[Determination of diacetyl in liquors by high performance liquid chromatography coupled with precolumn derivatization using 3,3'-diaminobenzidine].

A method was developed for the determination of diacetyl in liquors by high performance liquid chromatography-ultraviolet (HPLC-UV) coupled with precolumn derivatization using derivatization reagent 3,3'-diaminobenzidine (DAB). Diacetyl reacted with DAB at room temperature for 10 min. Then the separation was carried out on a high performance liquid chromatograph equipped with a diode array detector (DAD). A Shim-pack VP-ODS (250 mm×4.6 mm, 4.6 μ m) column was employed using water-methanol mobile phases for gradient at a flow rate of 0.7 mL/min and detection wavelength of 254 nm. The method showed a good linearity at diacetyl concentrations from 0.20 μ mol/L to 180 μ mol/L with the correlation coefficient () of 0.999. The limit of detection (=3) and limit of quantification (=10) were 0.09 μ mol/L and 0.20 μ mol/L, respectively. The intra-day precision (RSD) was 1.28% (=6). The method was further evaluated in the analysis of liquor samples with the recoveries ranging from 92.0% to 103.6% and RSDs from 0.69% to 3.45% (=3). The method is well suitable for the measurement of diacetyl in liquor samples.