Sanderson, M. P.. University of Georgia, mps@arches.uga.edu
Lomas, M. P.. University of Maryland, lomas@hpl.umces.edu
Glibert, P. M.. University of Maryland, glibert@hpl.umces.edu
Bronk, D. A.. University of Georgia, dbronk@arches.uga.edu

 
TOTAL DISSOLVED NITROGEN ANALYSIS: COMPARISON BETWEEN THE PERSULFATE, UV, AND HIGH TEMPERATURE OXIDATION METHODS
 
We compared the persulfate (PO), ultraviolet (UV), and high temperature (HTO) oxidation methods used to analyze total dissolved nitrogen (TDN) concentrations to determine whether the three methods differed in terms of standard parameters (blanks, limits of detection and linearity, and precision) or in oxidation efficiency of several standard compounds and freshwater and marine field samples. The PO method had the highest percent recoveries of the standard compounds tested (93 ± 13); the HTO method yielded recoveries of (87 ± 14; 91 ± 10 under optimized conditions). The UV method had the lowest percent recovery (71 ± 21), which appeared to be due to the hydrogen peroxide used as an oxidant; oxidation efficiency of the UV method increased substantially in subsequent trials (91 ± 12), when the PO reagent was used in place of 30% H2O2. The poor recovery of some standard compounds regardless of method suggests that concentrations of TDN, and subsequently DON, measured in the field will likely be underestimated to some degree depending on the composition of the TDN pool. With careful attention to details, however, the PO, UV with PO reagent, and HTO methods can provide reproducible results comparable to each other.
 
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
 
Code: SS34TU0282S