Hach DR2400 - Page 681

Phosphorus, Total
Phosphorus, Total
PhosphorusTot_UniCell_APD_Eng_Ody.fm Page 5 of 6
Method Performance
Precision
Standard: 7.5 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
Phosphate ions react with molybdate and antimony ions in an acidic solution to
form an antimonyl phosphomolybdate complex. Ascorbic acid reduces this
complex to phosphomolybdenum blue. Total phosphate measurements include
a digestion step while orthophosphate measurements exclude digestion. Test
results are measured at 880 nm.
Required Reagents
Description Unit Cat. No.
Phosphate - PO
4
3–
, LR, UniCell™ HCT 121 ................................................................... 23/pkg.............. HCT 121
Required Apparatus
Adapter, 16-mm Cell .......................................................................................................... each....................59457-00
Optional Apparatus
Cylinder, mixing, 100-mL graduated............................................................................... each....................20886-42
Digital Reactor Block 100................................................................................................... each....................DRB 100
Pipettor, Jencons, 100–1000 µL.......................................................................................... each....................27949-00
Rack, cooling, test tube ...................................................................................................... each....................18641-00
Tips, replacement for 27949-00 ......................................................................................... 400/pkg.............27950-00
Optional Standards
Hydrochloric Acid Solution, 1:1....................................................................................... 500 mL...................884-49
Phosphate Standard, 10-mL Voluette Ampule, 500-mg/L as PO
4
.............................. 16/pkg...............14242-10
Phosphate Standard, 10-mg/L as PO
4
............................................................................. 946 mL...............14204-16
Program 95% Confidence Limits of Distribution
806 7.2–7.8 mg/L PO
4
3–
Program Portion of Curve ∆Abs ∆Concentration
806 Entire range 0.010 0.2 mg/L PO
4
3–