A suggested method for the assay of vitamin B12 in sea water

Abstract

One of the difficulties encountered in the use of fresh water organisms for the assay of vitamin B₁₂ of marine origin is the elimination of salt from the extracts. This has suggested that a marine organism might be used with advantage. Indeed on several occasions marine or supra-littoral species have been proposed as possible assay subjects, but acceptable techniques await development (Lewin, 1954; Droop, 1954; Sweeney, 1954). Monochrysis lutheri, a supra-littoral euryhaline species, has advantages over others in being small, robust and giving heavy yields in synthetic media. The method employed in some Monochrysis assays carried out in the early spring of 1954 will be described.