Photo-Oxidation of Plasma

PLASMA can be made to take up oxygen when irradiated in the manner described in a previous paper [Harris, 1926], but the rate at which this occurs in the case of clear plasma is extremely slow. Exposure of 10 cc. of fresh goat's plasma in a dilution of 1 in 5 to the light of the quartz mercury vapour lamp ( kw.) at a range of 12-5 cm. causes an absorption usually of 4 mm.3 of oxygen per minute, i.e. 0 04 volume %; at this rate it would require an exposure of 25 minutes to enable plasma to take up 1 % of its own volume of oxygen. When these volumes of oxygen are again converted into masses the magnitudes are such that the analytical chemist either loses or ignores them. However, a variation appeared in the results with different samples of freshly drawn plasma and it was suspected that the discrepancies were due to incomplete centrifugalisation. The effect of the latter can be seen in the two examples: Goat 1 Goat 2 Centrifugalisation 1 hour 3 hours 1 hour 3 hours 02 uptake: vole. % per minute