Hach DR2400 - Page 645

Phosphorus, Reactive (Orthophosphate)
Phosphorus, Reactive (Orthophosphate)
PhosphorusReac_AVPP_Other_PV3_Eng_Ody.fm Page 5 of 6
Method Performance
Precision
Standard: 1.00 mg/L PO
4
3–
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
Summary of Method
Orthophosphate reacts with molybdate in an acid medium to produce a mixed
phosphate/molybdate complex. Ascorbic acid then reduces the complex, giving
an intense molybdenum blue color. Test results are measured at 880 nm.
Required Reagents
Quantity Required
Description Per Test Unit Cat. No.
PhosVer
™
3 Phosphate Reagent Powder Pillows, 10-mL.............1 pillow........... 100/pkg.............21060-69
or PhosVer
™
3 Phosphate Reagent AccuVac
®
Ampuls.....................1 ampule......... 25/pkg...............25080-25
Required Apparatus
Beaker, 50-mL............................................................................................1 ....................... each.................... 500-41H
Sample Cells, 10-mL, w/cap...................................................................2 ....................... 6/pkg.................24276-06
Stopper for 18-mm tube...........................................................................1 ....................... 25/pkg.................1731-25
Required Standards
Phosphate Standard Solution, 10-mL Voluette
®
Ampul, 50-mg/L as PO
4
................ 16/pkg...................171-10
Phosphate Standard Solution, 50-mg/L as PO
4
............................................................. 500 mL...................171-49
Phosphate Standard Solution, 1-mg/L as PO
4
............................................................... 500 mL.................2569-49
Water, deionized ................................................................................................................. 4 liters ....................272-56
Program 95% Confidence Limits of Distribution
490 0.97–1.03 mg/L PO
4
3–
492 0.98–1.02 mg/L PO
4
3–
Portion of Curve ∆Abs Program ∆Concentration
Entire range 0.010 490 0.02 mg/L PO
4
3–
Entire range 0.010 492 0.02 mg/L PO
4
3–