BS 2690-104:1983

0. Introduction
1. Scope
Section 104.1 Reactive silica: spectrophotometric
                method (reduced molybdosilicic acid)
2. Range
3. Maximum size of test portion
4. Principle
5. Interferences
6. Reagents
7. Apparatus
8. Sampling
9. Calibration
10. Procedure
11. Calculation
Section 104.2 Total silica: fusion and spectrophotometry
12. Range
13. Maximum size of test portion
14. Principle
15. Interferences
16. Reagents
17. Apparatus
18. Sampling
19. Calibration
20. Procedure
21. Calculation
Section 104.3 Suspended silica: filtration, fusion and
               spectrophotometry
22. Range
23. Maximum size of test portion
24. Principle
25. Interferences
26. Reagents
27. Apparatus
28. Sampling
29. Calibration
30. Procedure
31. Calculation

Reactive silica by formation of molybdosilicic acid, reduction to molybdenum blue and spectrophotometric measurement. Applicable to up to 50 μg of SiO₂ in up to 100 ml. Total silica by prior fusion to reactive silica. Applicable to up to 50 μg of SiO₂ in up to 50 ml. Suspended silica by prior filtration and fusion. Applicable to up to 50 μg of SiO₂ in up to 1 L.

The methods described are for the determination, in industrial waters, of reactive silica (spectrophotometry — reduced molybdosilicic acid), total silica (fusion and spectrophotometry) and suspended silica (filtration, fusion and spectrophotometry).

Section 104.1 Reactive silica: spectrophotometric method (reduced molybdosilicic acid)