1 Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstr. 111, CH-8903 Birmensdorf, Switzerland
The alkaline persulfate oxidation, converting all N into nitrate, is an easy and rapid method for determining total dissolved nitrogen. We found indications that atmospheric N is trapped during the oxidation step, which can be impeded by: (1) using always the same type of autoclave bottle and a constant sample volume; (2) minimising the remaining headspace in the bottle; (3) closing the bottle caps tightly for autoclavation; and (4) determining blanks for each test series.
Keywords: dissolved organic nitrogen, persulfate oxidation, total dissolved nitrogen