Phosphorus, Reactive (Orthophosphate)
Phosphorus, Reactive (Orthophosphate)
PhosphorusReac_AccuVac_Other_MOL_Eng_Ody.fm Page 3 of 6
Interferences
5. When the timer
beeps, place the blank
into the cell holder.
6. Touch Zero.
The display will show:
0.0 mg/L PO
4
3–
7. Place the prepared
sample into the cell
holder.
8. Touch Read.
Results will appear in
mg/L PO
4
3–
.
Table 1 Interfering Substances and Suggested Treatments
Interfering
Substance
Interference Levels and Treatments
Arsenate Only interferes if sample is heated.
Iron, ferrous Blue color caused by ferrous iron does not interfere if concentration is less than 100 mg/L.
Molybdate Causes negative interference above 1000 mg/L.
Silica Only interferes if sample is heated.
Sulfide
Causes a negative interference.
1. Measure 50 mL of sample into an Erlenmeyer flask.
2. Add Bromine Water (Cat. No. 2211-20) drop-wise with constant swirling until a permanent yellow color
develops.
3. Add Phenol Solution (Cat. No. 2112-20) drop-wise until the yellow color just disappears. Proceed with
step 3 (step 2 if using AccuVac procedure).
pH, extreme or
highly buffered
samples
May exceed buffering capacity of reagents. See Section 3.3 Interferences on page 41. May require
pretreatment. pH should be about 7.
Fluoride, thorium,
bismuth, thiosulfate
or thiocyanate
Cause negative interference.
Zero Read
To Next Page
Loading...
