METHODS FOR THE DETERMINATION OF DISSOLVED ORGANIC CARBON AND NITROGEN IN SEA WATER

Abstract

A method for the determination of organic N in solution in sea water is described in detail. The principle of Will-Warrentrap, involving digestion at 500[degree] C. with NaOH in hydrogen, is used. The sensitivity of the method is roughly 0.0003 mgm. N, giving an accuracy in sea water of about 5% in 5- or 10-ml. samples. A wet combustion method for the analytical determination of dissolved organic C in sea water is presented. Halides are removed with thallous sulphate, the evaporated sea water residue is oxidized by means of cericchromic sulphuric acid, and the evolved CO2 eventually determined by acid titration of baryta soln. through which the gases have passed. The accuracy approaches 0.1 mgm. C per liter. Differentiation between organic matter in colloidal and in true solution is made by analyses before and after ultrafiltration, using "Membranfilter Gesellschaft" collodion filters and a modification of the Thies?en ultrafiltration apparatus.