Nitric oxide (NO) is a short-lived intermediate of the oceanic nitrogen
cycle; however, due to its high reactivity, measurements of dissolved NO in
seawater are rare. Here we present an improved method to determine NO
concentrations in discrete seawater samples. The set-up of our system
consisted of a chemiluminescence NO analyser connected to a stripping unit.
The limit of detection for our ... [Show full abstract] method is 5 pmol NO in aqueous solution, which
translates into 0.25 nmol L−1 when using a 20 mL seawater sample
volume. Our method was applied to measure high-resolution depth profiles of
dissolved NO during a cruise to the eastern tropical South Pacific Ocean. It
is fast and comparably easy to handle; thus it opens the door for
investigating the distribution of NO in the ocean, and it facilitates
laboratory studies on NO pathways.