Phosphorus, Total
Phosphorus, Total
Page 4 of 6
PhosphorusTot_TNT_High_MOL_Eng_Ody.fm
Sampling and Storage
Collect samples in plastic or glass bottles that have been acid washed with 1:1
Hydrochloric Acid Solution (Cat. No. 884-49) and rinsed with deionized water.
Do not use commercial detergents containing phosphate for cleaning the
glassware used in this test.
Analyze samples immediately after collection for best results. If prompt analysis
is impossible, preserve samples up to 28 days by adjusting the pH to 2 or less
with concentrated Sulfuric Acid (about 2 mL per liter) (Cat. No. 979-49) and
storing at 4 °C. Warm the sample to room temperature and neutralize with 5.0 N
Sodium Hydroxide (Cat. No. 2450-53) before analysis. Correct for volume
additions; see Section 3.1.3 Correcting for Volume Additions on page 29.
Accuracy Check
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
Options. Touch Standard Additions. A summary of the standard
additions procedure will appear.
4. Touch
OK to accept the default values for standard concentration, sample
volume, and spike volumes. Touch
Edit to change these values. After values
are accepted, the unspiked sample reading will appear in the top row. See
Standard Additions in the instrument manual for more information.
5. Snap the neck off a 10-mL Voluette
®
Ampule of Phosphate Standard Solution,
500 mg/L as PO
4
3–
.
6. Prepare three sample spikes. Fill three mixing cylinders (Cat. No. 1896-40)
with 10 mL of sample. Use the TenSette Pipet to add 0.1 mL, 0.2 mL, and
0.3 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
Read. Each addition should reflect approximately 100% recovery or an
increase of 5 mg/L PO
4
3–
for each 0.1 mL of standard added.
8. 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
1. Use a 50-mg/L Phosphate standard in place of the sample. Perform the
procedure as described.
2. To adjust the calibration curve using the reading obtained with the 50-mg/L
PO
4
3–
Phosphate Standard Solution, touch Options on the current program
menu. Touch
Standard Adjust.
To Next Page
Loading...
