By the Persulfate Method

Each of these oxidation methods which have been used for analysis of dissolved organic matter in sea water have advantages and disadvantages which are summarized in Table IV. Oxidation by the persulfate method appears to be incomplete the photo-oxidation method seems to incompletely oxidize particles the dry oxidation method results in loss of volatile fraction during evaporation and drying steps. However, if proper precautions are followed and sample contamination is prevented, any of these oxidation methods can probably be used with confidence to measure organic carbon in sea water and to study the distribution of DOC in sea-water systems (Fig. 9). 

Skopintsev, B.A., 1976. On the determination of organic carbon in chloride rich water by the persulfate method. Oceanology, 16 630—633. 

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