2459300 Silica Reagent Set, 0.010-1.600 mg/L SiO₂

Article 2459300 measures silica in the range of 0.010-1.600 mg/L SiO₂ in boiler water and ultrapure water. Silica Reagent Set uses Heteropoly Blue method (8186). The product can be used to conduct analysis of 100 samples. Article 2459300 can be evaluated using all Hach spectrophotometers except DR820, DR2000, DR3000 and PC II. Silica Reagent Set may be used for 10 mL sample evaluation.

Silica Reagent Set includes:

• Amino Acid F Reagent Powder Pillows (p/n 2254069)
• Citric Acid Reagent Powder Pillows (p/n 2106269)
• Molybdate 3 Reagent Solution (p/n 199526)

Before starting analysis:

• It is recommended to collect the sample using clean plastic bottles with tight-fitting caps.
• It is not recommended to use glass bottles.
• It is required to analyze the sample as soon as possible for accurate testing results.

Procedure for SiO₂ evaluation

Start program 651 Silica LR to conduct silica determination in the range from 0.010 to 1.600 mg/L SiO₂. After that add 10 mL sample in the cell to prepare the blank. Fill another cell with 10 mL of boiler water or ultrapure water sample to prepare the sample. Pipet 14 drops of Molybdate 3 Reagent Solution in each cell. Then swirl each cell and start the instrument timer for 4 minutes. Pour the content of Citric Acid Reagent Powder Pillow to each cell and swirl the content of each cell. After 1 minute, add Amino Acid F Reagent Powder Pillow to the sample cell and swirl to mix. After 2 minutes, install the blank cell in the instrument and press ZERO. Finally, insert the pretreated sample cell and evaluate in the spectrophotometer at 815 nm or in the colorimeter at 610 nm.

Summary of method

Silica and phosphate in the sample enter into reaction with molybdate ion under acidic conditions forming yellow silicomolybdic acid complexes and phosphomolybdic acid complexes. Addition of citric acid destroys the phosphate complexes. Amino acid reduces the yellow silicomolybdic acid to intense blue color that is proportional to the silica concentration in the sample.