Summary Of Method - Hach POCKET COLORIMETER II Instruction Manual

Silica, HR,
continued

Summary of Method

Silica and phosphate in the sample react with molybdate ions under acidic
conditions to form yellow silicomolybdic acid complexes and phosphomolybdic
acid complexes. Addition of citric acid destroys the phosphate complexes. Silica is
then determined by measuring the remaining yellow color.
Required Reagents (Using Powder Pillows)
Description
High Range Silica Reagent Set (100 Tests)........................................... ........ 24296-00
Includes:
(1) Silica, HR Acid Reagent Powder Pillows, 100/pkg
(1) Citric Acid Reagent Powder Pillows, 100/pkg
(1) Molybdate Reagent Powder Pillows, 100/pkg
Optional Reagents
Silica Standard Solution, 10 mg/L .............................................. 500 mL ...... 1403-49
Silica Standard Solution, 25 mg/L .............................................. 236 mL .....21225-31
1—24
Units Cat. No.