Nitrogen, Ammonia
Nitrogen, Ammonia
Page 4 of 6
NitrogenAmm_TNT_Low_SAL_Eng_Ody.fm
7. After completing the sequence, touch Graph to view the best-fit line through
the standard additions data points, accounting for matrix interferences. Touch
View: Fit, then select Ideal Line and touch OK to view the relationship between
the sample spikes and the “Ideal Line” of 100% recovery.
See Section 3.2.2 Standard Additions on page 32 for more information.
Standard Solution Method
To check accuracy, use the Nitrogen Ammonia Standard Solution, 1.0 mg/L. Or,
dilute 1 mL of 50-mg/L Nitrogen Ammonia Standard Solution to 50 mL with
deionized water in a 50-mL volumetric flask.
Method Performance
Precision
Standard: 1.00 mg/L NH
3
–N
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
Ammonia compounds combine with chlorine to form monochloramine.
Monochloramine reacts with salicylate to form 5-aminosalicylate. The
5-aminosalicylate is oxidized in the presence of a sodium nitroprusside catalyst
to form a blue colored compound. The blue color is masked by the yellow color
from the excess reagent present to give a final green solution. Test results are
measured at 655 nm.
Program 95% Confidence Limits of Distribution
342 0.96–1.04 mg/L NH
3
–N
Portion of Curve ∆Abs ∆Concentration
Entire range 0.010 0.015 mg/L NH
3
–N
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