Fig. 2

CO bubbling. a CO is injected into a Ziploc bag containing the red blood cell solution until the bag is fully inflated. b The inflated bag is then vigorously shaken for at least 60 min, resulting in 90 % COHb production. c, d The sample solution, now in a beaker, is simultaneously exposed to light (500,000 lux, 300,000 lux, or simply room light) and to a continuous flow of oxygen at 50 mL/min. The oxygen is delivered via a copper nozzle connected to an oxygen gas cylinder