海水のビタミンB<sub>12</sub>に関する研究-II

Abstract

We have formerly reported on a method presented to determine the vitamin B12 in sea water. On that occasion sample sea water was previously desalted by dialysis against running fresh water, using cellophane as diaphragm, so that the vitamin B12 content might be properly estimated by the Euglena method. In the present experiment we confirmed the superiority of electrodialysis over running water dialysis, and also examined the stability of vitamin B12 in sea water. The results obtained were as follows. Desalting of sea water was found to be accomplished in a shorter time by electrodialysis than by running water dialysis (Table 2). As to the stability of vitamin B12 in sea water, on the other hand, it was made clear that: 1) Loss of vitamin Bit in sea water proceeds with a considerable velocity in diffused day light, while the loss is evaded almost completely even throughout 20 days storage if the sea water is kept in brown light or in the dark (Table 3). 2) Intentional neutralization or acidification of natural sea water lessens the rate of loss of vitamin B12 in diffused day light; but such processing is never to be looked on as a conclusive way of keeping the vitamin B12 perfectly fixed (Table 4). 3) In a sea water being exposed to the sun, its vitamin B12 content decreases very rapidly (Table 5).