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13.
Install the 16-mm
adapter.
Note: See Section 2.6 in the
Instrument Manual for
installation details.
Place the sample vial into
the adapter.
Interferences
Interfering Substance
Arsenate
Iron, ferrous
Molybdate
Silica
Extreme pH or highly
buffered samples
Fluoride, thorium,
bismuth, thiosulfate or
thiocyanate
Temperature, Cold (less
than 18 °C)
Temperature, Hot (greater
than 25 °C)
The following do not interfere in concentrations up to 1000 mg/L:
Pyrophosphate, tetraborate, selenate, benzoate, citrate, oxalate, lactate, tartrate, formate, salicylate, Al
2+
2+
+
+
+
Ba
, Sr
, Li
, Na
, K
, NH
–
–
2–
–
AsO
, Br
, CO
, ClO
, CN
3
3
4
* Gentle warming of the sample to reach room temperature will not cause this substance to interfere.
PhosphorusTot_TNT_High_MOL_Eng_Ody.fm
Zero
14.
Touch
.
Zero
The display will show:
3–
0.0 mg/L PO
4
Large amounts of sample turbidity may cause inconsistent results in the test
because the acid present in the reagents may dissolve some of the suspended
particles and because of variable desorption of orthophosphate from the
particles.
The following may interfere when present in concentrations exceeding these
listed below:
Causes positive interference if the sample is heated.*
Blue color caused by ferrous iron does not interfere if iron concentration is less than 100 mg/L.
Causes negative interference above 1000 mg/L.
Causes positive interference if the sample is heated.
May exceed buffering capacity of the reagents. See Section 3.3 Interferences on page 41. Samples
may require pretreatment. Sample pH should be about 7.
Cause a negative interference.
Cause a negative interference.
Causes a positive interference.
Post-digestion samples should be brought to room temperature (18–25 °C) before the addition of
the Molybdovanadate Reagent or sodium hydroxide.
+
2+
2+
–
–
, Cd
, Mn
, NO
, NO
, SO
4
3
2
–
–
4–
, IO
, SiO
.
3
4
15.
Place the prepared
sample into the cell
adapter.
Interference Levels and Treatments
2–
2–
2+
+
2+
, SO
, Pb
, Hg
, Hg
4
3
Phosphorus, Total
Read
16.
Touch
.
Read
Results will appear in
3–
mg/L PO
.
4
3+
3+
2+
, Fe
, Mg
, Ca
2+
2+
2+
+
4+
, Sn
, Cu
, Ni
, Ag
, U
, Zr
Phosphorus, Total
Page 3 of 6
2+
,
4+
,
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