calibrant to 10-mL volumes of each sample. Average nitrate
recovery was 101% for the CdR method and 102% for the
NaR method. Nitrite concentrations in these samples were
less than 0.01 mg of NO2
- -N/L. Results for between-run
duplication of nitrate concentrations for samples used for
the spike recovery experiments are listed in Table 6. Differences
between duplicate results were typically about 0.01
mg of NO3
- -N/L. Table 7 provides concentrations determined
for paired nitrite and nitrate solutions (each with a
nominal concentration of 1.00mg-N/L) that were determined
at approximate intervals of 20 samples to assess completeness
of nitrate reduction during the course of each run. Reduction