V O L U M E 19, N O . 9
E46
sensitivity, D,is deflection for oxygen saturation at solids content of sample read from Table 111, S is solubility of oxygen at temperature and solids content of sample, also read from Table 111.
Royal North Shore Hospital, Sydney, for making available the facilities of the institute for portions of the investigation. LITERATURE CITED
PERFORMANCE
While it is difficult to make a satisfactory assessment of the accuracy of the method owing t o the number of factors involved, it is considered that oxygen contents down to about 0.02 ml. per 100 ml. of orange juice are determined with a precision better than *5% and probably better than *3%, and oxygen coqtents down to about 0.002 ml. per 100 ml. are detectable. More sensitive current-measuring equipment than was available to the authors would improve the sensitivity of the method. The amperometric method is very much more rapid than any method previously available, a single determination being completed in about one minute, apart from the determination of the residual current. It is being used successfully in laboratory studies of oxygen consumption by orange juice and for process control in orange jJice deaeration. No interference from dissolved metals has been observed in a few samples of stored canned orange juice examined. It is expected that the method will be applicable to other citrus juices, such as grapefruit juice and lemon juice, and to fruit juices in general, although indppendent calibration in each product may be necessary.
Baumberger, J. P., Cold Spring Harbor Symposia Quant. Biol., 7, 196-215 (1939). Breyer, B., private communication. Gigubre, P. A., and Lauzier, L., Can. J . Research, 23B, 76-83 (1945).
Hartman, G . H., and Garrett, 0. F., IND.ENG.CHEM.,ANAL. ED.,1 4 , 6 4 1 - 4 (1942). Hume, D. N., and Harris, W. E., Zbid., 15, 465 (1943). Ingols, R. S., Ibid., 14, 256-8 (1942). Ingols, R. S.,Sewage W o r k s J . , 13, 1097-109 (1941). Karsten, S., Am. J . Botany, 25, 145 (1938). Kolthoff, I. M., and Lingane, J . J., “Polarography,” New York, Interscience Publishers, 1941. Landolt-Bornstein, “Physikalisch-Chemische Tabellen,” 5 Aufl., Bd. 1, p. 765, Berlin, Julius Springer, 1923. Lindquist, J . R., Food Industries, 19, 182-3, 212, 214, 216 (1947).
Lingane, J. J., and Kerlinger, H., IND.ENG. CHEM.,ANAL. ED.,12,750-2 (1940). Lingane, J . J., and Loveridge, B. A., J . Am. Chem. Sac., 66, 1425-31 (1944).
Loeffler, H. J., IND.ENG.CHEM.,ANAL.ED.,12, 5 3 3 4 (1940). Manning. W. M . , Ecology, 21,509-12 (1940). Petering, H. G., and Daniels, F.. J . Am. Chem. Soc., 60, 2796802 (1938).
Peters, J. P., and Van Slyke, D. D., “Quantitative Clinical Chemistry,” Vol. 2, Baltimore, Williams & Wilkins Co., 1932.
ACKNOWLEDGMENTS
Pulley, G. N.,and Von Loeseoke, H. W., 2nd. Eng. Chem.. 31,
Thanks are due to J. F. Kefford for suggesting the problem and continued interest in the work, to B. Breyer and F. E. Huelin for helpful suggestions, to Miss H. Smith for technical assistance, and to the director of the Kolling Institute of Medical Research.
1275-9 11939), \ - - -
Sharp- P. F., Hand, D. B., and Guthrie, E. S., IND. ENG.CHEM.. ASAL.ED.,13,593-7 (1941). Vitek. V., Collection Czechoslov. Chem. Commun., 7, 5 3 7 4 7 \
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