To establish a method for simultaneous determination of kojic acid and 2-mercapto-5-methyl-1,3,4-thiadiazole (MMTD) in flour and flour improver by HPLC.MethodsSeparation was achieved on an Atlantis C₁₈ column (4.6 mm ×15 cm, 5 μm) with the mobile phase of acetonitrile and 0.1% phosphoric acid solution. Gradient elution was used with the flow rate of 1.0 ml/min. The injection volume was 1μl and the detection wavelength was 269 nm for kojic acid and 300 nm for MMTD. Kojic acid and MMTD in samples were extracted by acetonitrile. After centrifugation and filtering, sample solutions were analyzed by HPLC. ResultsKojic acid and MMTD both showed good linearity in the range of 0.5-20 μg/ml. The average recoveries were in the range of 84.2%-92.4% (RSD 1.1%-6.9%, n=6). Limit of detection (LOD) of kojic acid and MMTD were 2.0 and 0.7 mg/kg, respectively.ConclusionThe method can be used for the determination of kojic acid and MMTD in flour and flour improver.