Determination of S in extracted leaf protein

The oxygen‐combustion technique for converting organic S to sulphur oxides, absorbing these in hydrogen peroxide, and determining the sulphate formed by measuring the amount of chloranilic acid it releases from an excess of barium chloranilate, was found to give satisfactory recoveries of S from methionine and cystine. This method for determining S was then applied to extracted leaf protein concentrates, almost all of whose S is derived from methionine and cyst(e)ine.