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Phosphorus, Total
Accuracy Check
* See 40 CFR 136.3
Phosphorus, Total
Page 4 of 6
For wastewater samples
*
samples
by adjusting the pH to 2 or less with Sulfuric Acid, 5.25 N
(Cat. No. 2449-00) and storing the sample at 4 °C for up to 28 days. The pH can
be checked using pH Paper (Cat. No. 391-33). Do not use mercury compounds
as preservatives. Warm samples to room temperature before analysis.
Standard Additions Method (Sample Spike)
1. Clean glassware with 1:1 Hydrochloric Acid Standard Solution. Rinse again
with deionized water. Do not use detergents containing phosphate to
clean glassware.
2. After reading test results, leave the sample cell (unspiked sample) in the
instrument. Verify the chemical form.
3. Touch
. Touch
Options
additions procedure will appear.
4. Touch
to accept the default values for standard concentration, sample
OK
volume, and spike volumes. Touch
are accepted, the unspiked sample reading will appear in the top row. See
3.2.2 Standard Additions for more information.
5. Snap the neck off a 10-mL Voluette
3–
500-mg/L as PO
.
4
6. Prepare three sample spikes. Fill three mixing cylinders with 100 mL of
sample. Use a pipet to add 0.2 mL, 0.4 mL, and 0.6 mL of standard,
respectively, to each cylinder. Mix well.
7. Analyze each sample spike as described in the procedure above, starting with
the 0.1 mL sample spike. Accept each standard additions reading by touching
. Each addition should reflect approximately 100% recovery.
Read
8. 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. Use a 10-mg/L PO
4
Perform the phosphate procedure as described.
2. To adjust the calibration curve using the reading obtained with the
3–
10-mg/L PO
Phosphate Standard Solution, touch
4
program menu. Touch
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
For more information, see Section 3.2.4 Adjusting the Standard Curve on page 40.
— If prompt analysis is impossible, preserve
. A summary of the standard
Standard Additions
to change these values. After values
Edit
®
Ampule of Phosphate Standard Solution,
Graph
and touch
Ideal Line
OK
3–
standard solution listed under Optional Standards.
.
Standard Adjust
to accept the displayed concentration (the value
to view the best-fit line through
to view the relationship between
on the current
Options
PhosphorusTot_UniCell_APD_Eng_Ody.fm
.
OK
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