Electrosorption of vitamin K1 at mercury and its determination at submicrogram levels by differential pulse voltammetry at a hanging mercury electrode

The electrochemical behaviour of vitamin K₁ has been studied in ethanolic and methanolic acetate buffers by cyclic voltammetry and differential pulse voltammetry (d.p.v.) at the h.m.d.e. and differential pulse polarography at the d.m.e. Increased adsorption occurs at the mercury electrode as the percentage of water is increased. The most sensitive signal was obtained by d.p.v. with acetate-buffered 60% methanolic solutions; vitamin K₁ could then be measured down to 10 ng ml^-1.