Oxygen reaction vessels.
Transcutaneous oxygen electrodes were modified to be more suitable as a component of oxygen reaction vessels. The temperature control system was removed from the transcutaneous electrode to decrease the thickness and improve the stability. The temperature control system was incorporated in the metal sleeve surrounding the glass reaction vessel to shorten the distance between the magnetic stirrer and stirring bar, enabling smooth stirring with a short magnetic bar. With these modifications, we have succeeded in reducing the vessel volume to about 0.5 ml, or two to four times smaller than reaction vessels incorporating unmodified transcutaneous electrodes (vessel volume = 1-2 ml) and about twenty times smaller than reaction vessels using rod-shaped Clark electrodes (vessel volume about 10 ml). In another vessels modified as above, two optical guides were connected to the metal sleeve for irradiating the solution and receiving transmitted light simultaneously to enable simultaneous measurements of oxygen concentration absorption spectra. The relationship between oxygen concentration and absorption spectra of Hb is described as an application of this vessel.