Abstract: Vitamin K₁ (VK₁) and K₃ (VK₃) were determined simutaneously by adsorption voltam-metry in 0.04 mol/L Na₂SO₄ solution.The peaks of derivative waves were obtained at - 0.09V(SCE) for VK₁ in solution with pH= 4.0～4.3 and at - 0.65V for VK₃ when pH= 1.70～1.85.The peak currents were directly proportional to the concentrations of VK₁ and VK₃ overthe ranges of 1.0×10^-9～8.0×10^-7 mol/L and 6.0×10^-10～8.0×10^-7 mol/L respectively.The method has been used for determination of VK₁ and VK₃ in some traditional Chinesemedicines.

Key words: voltammetry, vitamin K₁, vitamin K₃