polyphosphate to orthophosphate. Phosphate analysis is based on the
antimony-molybdate method. Orthophosphate reacts with molybdate
and antimony in an acidic solution to form an antimonyphosphomolybdate complex, which is then reduced by ascorbic acid,
forming a blue color. For determining the DOP, there is no direct way as
with dissolved organic carbon or nitrogen. Total phosphorus can be
used to calculate DOP by subtracting the other P pools (POP could also
be removed by first filtering the sample).
2 Materials
Use only analytical grade reagents.
2.1 Phosphate and
Dissolved Organic
Phosphorus from Total
Phosphorus
Measurements
1. Ammonium heptamolybdate tetrahydrate ((NH 4 ) 6 Mo 7 O 24 Á4H 2 O).
2. Ascorbic acid (C 6 H 8 O 6 ).
3. Potassium persulphate (K 2 S 2 O 8 ).
4. Potassium antimony tartrate (K(SbO)C 4 H 4 O 6 ).
5. Potassium dihydrogen phosphate (KH 2 PO 4 ).
6. Concentrated sulfuric acid (96% H 2 SO 4 ).
7. Concentrated hydrochloric acid (37% HCl).
8. Ultrapure water (e.g., Milli-Q).
9. 50 ml reaction flasks (e.g., Erlenmeyer flasks for manual phosphate analysis).
10. 25–50 ml reaction flasks with screw caps (e.g., Pyrex containers
for total phosphorus).
11. 50 ml graduated cylinders.
12. 100 ml volumetric flasks.
13. 100–250 ml storage bottles.
14. Adjustable pipettes and pipette tips.
15. Spatulas.
16. Analytical balance.
17. Refrigerator.
18. Autoclave.
19. Spectrophotometer or automatic analyzer.
20. 1–5 cm quartz glass cuvette (for manual analysis).
21. 0.7 μm glass fiber filters (25 mm Ø) and Swinnex filter holders.
22. 50 ml disposable sterile syringes.
23. Oven (450
C).
2.2 Particulate
Organic Phosphorus
1. 0.7 μm glass fiber filters (25 mm Ø).
2. Concentrated sulfuric acid (96% H 2 SO 4 ).
3. Concentrated hydrochloric acid (37% HCl).
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Jaana Koistinen et al.
antimony-molybdate method. Orthophosphate reacts with molybdate
and antimony in an acidic solution to form an antimonyphosphomolybdate complex, which is then reduced by ascorbic acid,
forming a blue color. For determining the DOP, there is no direct way as
with dissolved organic carbon or nitrogen. Total phosphorus can be
used to calculate DOP by subtracting the other P pools (POP could also
be removed by first filtering the sample).
2 Materials
Use only analytical grade reagents.
2.1 Phosphate and
Dissolved Organic
Phosphorus from Total
Phosphorus
Measurements
1. Ammonium heptamolybdate tetrahydrate ((NH 4 ) 6 Mo 7 O 24 Á4H 2 O).
2. Ascorbic acid (C 6 H 8 O 6 ).
3. Potassium persulphate (K 2 S 2 O 8 ).
4. Potassium antimony tartrate (K(SbO)C 4 H 4 O 6 ).
5. Potassium dihydrogen phosphate (KH 2 PO 4 ).
6. Concentrated sulfuric acid (96% H 2 SO 4 ).
7. Concentrated hydrochloric acid (37% HCl).
8. Ultrapure water (e.g., Milli-Q).
9. 50 ml reaction flasks (e.g., Erlenmeyer flasks for manual phosphate analysis).
10. 25–50 ml reaction flasks with screw caps (e.g., Pyrex containers
for total phosphorus).
11. 50 ml graduated cylinders.
12. 100 ml volumetric flasks.
13. 100–250 ml storage bottles.
14. Adjustable pipettes and pipette tips.
15. Spatulas.
16. Analytical balance.
17. Refrigerator.
18. Autoclave.
19. Spectrophotometer or automatic analyzer.
20. 1–5 cm quartz glass cuvette (for manual analysis).
21. 0.7 μm glass fiber filters (25 mm Ø) and Swinnex filter holders.
22. 50 ml disposable sterile syringes.
23. Oven (450
C).
2.2 Particulate
Organic Phosphorus
1. 0.7 μm glass fiber filters (25 mm Ø).
2. Concentrated sulfuric acid (96% H 2 SO 4 ).
3. Concentrated hydrochloric acid (37% HCl).
88
Jaana Koistinen et al.