Abstract: [Objective]An analytical method for the simultaneous determination of vitamin K₁ and K₂ in dairy products by high performance liquid chromatography-fluorescence detector was established.[Method]The samples were hydrolyzed by lipase,extracted with n-hexane after saponification,derivatized by zinc powder reduction column,determined by high performance liquid chromatography-fluorescence detector and quantified by external standard method.[Result]Peaks of vitamin K₁ and K₂ were separated within 15 mins.The linear range was good in the concentration of 0.1~1.6 μg/mL,and the correlation coefficient was ≥0.99.When the sample volume was 5 g and the constant volume was 5 mL,the detection limit of vitamin K₁ and K₂ was 2 μg/100g,and the quantitation limit was 6 μg/100g.When the addition amount was 5~50 μg/100g,the recovery rate of vitamin K₁ was 61.0% to 108.5%,the precision RSD was 1.1% to 9.3%,the recovery rate of vitamin K₂ was 75.6% to 104.0%,and the RSD was 2.0% to 6.6%,which met the requirements of precision and recovery.[Conclusion]The established method had good recovery rate,high accuracy and good repeatability,and could detect the content of vitamin K₁ and K₂ in dairy products.

Key words: dairy product, vitamin K₁, vitamin K₂, high performance liquid chromatography-fluorescence detection method