Phosphorus, Reactive (Orthophosphate)
Phosphorus, Reactive (Orthophosphate)
PhosphorusReac_AVPP_Other_PV3_Eng_Ody.fm Page 3 of 6
Interferences
Sample Collection, Storage, and Preservation
Collect sample in plastic or glass bottles that have been cleaned with
1:1 Hydrochloric Acid Solution (Cat. No. 884-49) and rinsed with deionized
water. Do not use commercial detergents containing phosphate for cleaning
glassware used in phosphate analysis.
5. Touch the timer icon.
Touch
OK.
A two-minute reaction
period will begin.
If the sample was digested
using the Acid Persulfate
digestion, a ten-minute
reaction period is
required.
6. When the timer
beeps, wipe the blank
and place it into the cell
holder.
7. Touch Zero.
The display will show:
0.00 mg/L PO
4
3–
8. Wipe the prepared
sample and place it into
the cell holder.
Touch
Read.
Results will appear in
mg/L PO
4
3–
.
Interfering Substance Interference Levels and Treatments
Aluminum Greater than 200 mg/L
Arsenate Interferes at any level.
Chromium Greater than 100 mg/L
Copper Greater than 10 mg/L
Hydrogen Sulfide Interferes at any level
Iron Greater than 100 mg/L
Nickel Greater than 300 mg/L
pH, excess buffering
Highly buffered samples or extreme sample pH may exceed the buffering capacity of the
reagents and require sample pretreatment. pH 2–10 is recommended.
Silica Greater than 50 mg/L
Silicate Greater than 10 mg/L
Turbidity (large amounts) or
color
May cause inconsistent results because the acid in the powder pillow may dissolve some of the
suspended particles and because of variable desorption of orthophosphate from the particles.
For highly turbid or colored samples, add the contents of one Phosphate Pretreatment Powder
Pillow (Cat. No. 14501-99) to 25 mL of sample. Mix well. Use this solution to zero the instrument.
Zinc Greater than 80 mg/L
10 mL
Zero
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