Following experimental results were obtained regarding the mechanism on the removal of Pyrogen^× (TBP-reaction positive substance) by quinone treatment of pyrogen solution:
1) Quinone treatment was carried out on pyrogen solution, in the original high concentration and in lower concentration of 400 dilution and both were found to give negative TBP reaction of practically the same degree of coloration.
2) In the treatment of quinone-treated solution with activated carbon, experiments were carried out with varied length of time of contact and at varied temperatures. When treated at a high temperature or for a long time, TBP reaction remained positive and a fairly large amount of Pyrogen^× seemed to be present. On the other hand, when the carbon treatment was carried out at a room temperature or as short a time as possible, TBP reaction was found to become negative.
3) When the activated carbon used for the adsorption of the quinone treatment solution is heated in distilled water and filtered, the filtrate was found to give positive TBP reaction from which it became certain that the Pyrogen^× adsorbed on the activated carbon is again liberated into water.
4) It was clarified that when this liberated Pyrogen^× is treated again with quinone, the solution would again give negative TBP reaction.
5) Adsorptive removal of Pyrogen^× by carbon added with quinone-like substance was found to be ineffective.
From the foregoing results it was assumed that TBP-reaction positive substances (Pyrogen^×) behaved in the same manner against quinone treatment and further, that the Pyrogen^× removal by quinone treatment was effected by the following formulae:
P^×+Q→P^×Q P^×Q+C→CP^×Q→CQ+P^× where P^× is Pyrogen^×, Q, ρ-quinone, and C, activated carbon.