Cuvette and flow system for simultaneous determination of optical density and oxygen concentration

The major components of the device for semiautomatic measurement of oxygen consumption and optical density changes are a thermostated glass reservoir of 50-250 ml for the reaction mixture, a roller pump to transport the reaction mixture from the reservoir into the measuring cuvette, and a stoppered glass cuvette equipped with a Clark type electrode. The glass cuvette (0.525 ml) is square shaped (the interior section 6 X 6 mm). The lower part housing the magnetic stirrer has a side aperture for the oxygen electrode. The upper part of the cuvette is cylinder shaped. The stopper is fitted in this part. The stopper made of lucite protrudes 15 mm into the cuvette. The access and the removal of the reaction mixture to/from the cuvette is ensured by three different channels machinated into the body of the stopper. The device adaptable to Eppendorf spectralline photometer may be used in the study of oxidative phosphorylation on intact mitochondria or submitochondrial particles, or of any oxygen consuming system in which one reagent or reaction product can be monitored photometrically.