Respirometers are widely used to study biological and chemical processes which involve the consumption of oxygen. They are used, for example, to measure the biochemical oxygen demand (BOD) of waste-waters and streams. The standard Warburg BOD technique employs a manometer in a closed system to measure small decreases of oxygen pressure indicative of the rate and extent of reaction under study. The Warburg technique requires that readings be taken manually over extended periods of time -- for example, one week. This paper describes an automated, recording respirometer which eliminates the need for this constant attention.Oxygen, produced by electrolysis, is maintained at constant pressure in each individual respirometer cell via regulation of the amount of time the oxygen is produced. In its present configuration, six reaction vessels are simultaneously controlled by individual cell modules. The amount of oxygen consumed in each reaction vessel is totalized separately and printed out on command of a logic unit at predetermined time intervals, which can be varied from 15 minutes to 10 hours. This logic unit can accommodate up to 99 individual cell control modules with printout in any desired sequence.Typical results obtained, as well as advantages of the apparatus (such as extensive reduction in labor time to set up and carry out the tests and reduce the data), are discussed in the paper.
展开▼
