184 



of the elements in the sea, our understanding of the processes in which they are 

 involved is very limited. For example, sea bottom deposits have been found 

 which contain 15 to 20% manganese, yet our knowledge of how this accumulation 

 takes place from a reservoir of manganese of only a few thousandths of a part 

 per million is incomplete. Vitamin Bi2> known to be produced in excess of their 

 own requirements by some organisms and to be required by others in amounts 

 greater than furnished by their metabolism, contains an atom of cobalt in each 

 vitamin molecule. Cobalt, then, is directly involved in the metabolism of one 

 group of organisms and indirectly, through a B12 requirement, in that of another 

 group. Yet, primarily because methods of concentrating cobalt by a factor 

 great enough to bring it into the range required by analytical procedures have not 

 been available, it is not known whether the cobalt requirement of the B12 produ- 

 cer organisms is always met in the oceans. Similarly, little is known about the 

 distribution of vitamin B12 in the ocean. 



To design a single concentrating system that would be useful for all situ- 

 ations obviously is impossible. The differences in concentrations and of chemi- 

 cal behavior of the many inorganic and organic substances that may be of interest 

 suggests that each situation will have to be treated by itself. Nevertheless, a 

 few general requirements for all systems can be stated. Analysis for dissolved 

 organic constituents probably should be carried out as soon after taking the 

 sample as possible to prevent changes in the constituent by bacterial action, etc. 

 Under these conditions the concentrating system should meet the requirements 

 suggested for a seagoing instrument. Two additional requirements seem de- 

 sirable for most concentrating systems. They are, (1) concentration factors of 

 10^ or 104 should be possible under conditions that will not limit the accuracy 

 and precision of modern analytical methods, and (2) all techniques should pro- 

 vide as complete a separation as possible of the trace substance from the major 

 constituents. 



It is possible to speculate on some of the instrumentation problems that 

 will accompany attempts to concentrate various trace constituents. It seems 

 reasonable that most methods will be built around existing techniques with modi- 

 fications being developed to meet the requirements of marine systems and of 

 seagoing operation. 



Ion exchange resins have been widely used in many kinds of separation 

 precedures. The equipment needed in most applications is extremely simple, 

 iaeing little more than glass or plastic tubes packed with the granulated resin, 

 and in some applications a vacuum or pressure pump to force the sample through 

 the column. A promiising application of exchange resins in sea water analysis 

 is that of removing inorganic constituents prior to analysis or concentration of 

 certain dissolved organic substances. In order to be non-reactive with the 

 resins, the organic compounds should be non-ionic or capable of being made 

 nearly so, in which case they will pass through the column. Under some cir- 

 cumstances substances retained by the resins can be eluted from the column 

 with appropriate solvents. Samuelson (1953) has summerized the information 

 concerning the uses of ion exchange resins in analytical chemistry. Provasoli 

 and Carritt (unpublished results) used a mono-bed exchange column containing 

 IR-120 and IRA-410 to deionize sea water prior to performing a bio-assay for 

 vitamin Bi2- The separation was necessary as the assay organism had a low 

 salinity tolerance. Chromatographic columns, some of which use commercial 

 ion exchange resins, appear to have many applications to problems in chemical 

 oceanography, especially to the separation and identification of substances with 

 similar chemical properties. 



A column technique was developed by Carritt (in press) for the separa- 



