185 



tion of copper, cobalt, zinc, lead, cadmium, and manganese from natural wat- 

 ers, including sea water. The column consisted of granulated cellulose acetate 

 which had been treated with a dithizone-carbon tetrachloride solution. Recovery 

 was good with solutions containing as little as a microgram of test substances per 

 liter, and separation from the major constituents was excellent. 



The January number of Analytical Chemistry has since 1949 contained a 

 number of review articles dealing with various aspects of the field. Included 

 are sections on Ion Exchange, Extraction, Chromatographic Separation, and In- 

 strumentation. These reviews are convenient starting points in the search for 

 analytical methods that may have applications to oceanographic problems. 



RADIOCHEMICAL MEASUREMENTS 



The instrumentation of radiochemical procedures is not strictly a prob- 

 lem of the instrumentation of oceanographic measurements. However, the ap- 

 plicability of radio tracer techniques to many oceanographic problems, dating 

 procedures which require the measurement of very low level activities of natu- 

 ral radio elements, and the possible application of activation analysis to the de- 

 termination of trace constituents suggests that the handling and measurement of 

 radioisotopes should be familiar to workers in oceanography. 



Kierstead (1952) in a discussion of Application of Radioactivity to Ocea- 

 nography outlines most of the topics mentioned above and gives a general state- 

 ment of the kind of laboratory and the instruments needed to carry out the 

 measurements. Goldberg, Walker, and Whisenand (1951) report the results of 

 an ecological study in which radiophosphorus was used to trace the utilization 

 and regeneration of phosphorus by diatoms. The publications of Libby et al. 

 (1949) and more recently of Kulp (1951) describe the measurement of carbon-14 

 as a method of determining the age of carbonaceous materials. 



An interesting calculation indicates the possible utility of activation anal- 

 ysis in oceanographic problems. It can be shown that the residue from approxi- 

 mately 25 miilliliters of sea water when exposed to the neutron flux in an Oak 

 Ridge pile for 100 hours will contain a gold activity (Au^^S) having an initial dis- 

 integration rate of approximately 6000 dis. /min. , an activity well within the 

 limits of accurate counting. The concentration of gold in sea water is approxi- 

 mately 6 X 10"° milligrams per kilogram. 



POLAROGRAPHIC MEASUREMENTS 



The polarograph has become a useful analytical tool for the determina- 

 tion of many metallic ions as well as dissolved organic substance in concentra- 

 tions down to approximately 10"^ molar. Kolthoff and Lingane (1952) and Mull- 

 er (1951) give a complete account of the polarographic method. Unfortunately, 

 the concentration of most sea water constituents which might be determined 

 polarographically is below this limit. Dissolved oxygen, however, is present 

 in concentrations within the optimum range of operation of the instrument. The 

 precision that can be obtained by this method is greater than can be realized with 

 the usual Winkler titration, especially with solutions of low oxygen content. 



The dropping mercury electrode, used in most polarographic procedures, 

 cannot be used on shipboard or in systems in which the sample is in motion. 

 Manning (1940) followed the variation in dissolved oxygen in a lake by mounting 

 a dropping mercury electrode on a stake driven firmly into the bottom. The 

 recording equipment was on shore. Giguere and Lauzier (1945) describe the 

 use of the dropping mercury electrode and both fixed and rotating platinum mi- 



