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Nitrogen, Total
Method Performance
Nitrogen, Total
Page 4 of 6
4. Prepare three sample spikes by filling three mixing cylinders with 50 mL of
sample. Use a pipet to add 0.2, 0.4, and 0.6 mL of 1000-mg/L NO
Standard, respectively, to each sample and mix thoroughly.
5. Analyze each sample spike as described in the procedure above, starting with
the 0.2 mL sample spike. Accept each standard additions reading by touching
Read. Each addition should reflect approximately 100% recovery. The
nitrogen concentration should increase by approximately 4, 8, and
12 mg/L N, respectively.
6. After completing the sequence, touch
the standard additions data points, accounting for matrix interferences. Touch
, then select
View: Fit
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
1. Prepare a 20.0-mg/L NO
1000-mg/L NO
–N into a 100-mL volumetric flask. Dilute to the mark with
3
deionized water. Stopper and invert to mix.
2. To adjust the calibration curve using the reading obtained with the
20.0-mg/L N standard solution, touch
Touch
Standard Adjust
3. Touch
. Touch
On
Adjust
depends on the selected chemical form). If an alternate concentration is used,
touch the number in the box to enter the actual concentration, then touch
Touch
.
Adjust
See Section 3.2.4 Adjusting the Standard Curve on page 40 for more information.
Precision
Standard: 20.0 mg/L NO
Program
800
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
Program
800
See Section 3.4.5 Sensitivity on page 44 for more information.
Graph
and touch
Ideal Line
OK
–N standard solution by pipetting 2.00 mL of
3
Options
.
to accept the displayed concentration (the value
–N
3
95% Confidence Limits of Distribution
15.2–24.8 mg/L N
Portion of Curve
Entire range
–N
3
to view the best-fit line through
to view the relationship between
on the current program menu.
∆Abs
∆Concentration
0.010
0.6 mg/L N
NitrogenTot_UniCell_Other_PSD_Eng_Ody.fm
.
OK
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