2271900 Alkalinity Reagent Set, 10-4000 mg/L CaCO₃

Article 2271900 measures alkalinity in the range of 10-4000 mg/L CaCO₃ in oil and gas field waters. The product uses Phenolphthalein and Total Alkalinity method (8203). Each product package can be used to conduct analysis of 100 samples.

Alkalinity Reagent Set includes:

• Bromcresol Green-Methyl Red Reagent Powder Pillows (p/n 94399)
• Phenolphthalein Indicator Powder Pillows (p/n 94299)
• Sulfuric Acid Titration Cartridge (p/n 1438801)
• Sulfuric Acid Titration Cartridge (p/n 1438901)

Before starting analysis:

• It is recommended to collect the sample in clean glass or plastic bottles with tight-fitting caps.
• It is required to prevent agitation of the sample and exposure to the air.
• It is necessary to analyze the sample immediately after collection to receive precise testing results.

Procedure for CaCO₃ determination

Insert clean delivery tube into the Sulfuric Acid Titration Cartridge and attach the cartridge to the Digital Titrator. Swirl the collected sample and the content of Phenolphthalein Indicator Powder Pillow in the 250mL Erlenmeyer flask. Add titrant using Digital Titrator until the color changes from pink to colorless (or until the pH is 8.3). Then calculate the concentration using multiplier (see manual for detailed information regarding sample volumes and digit multipliers). After that add Bromcresol Green-Methyl Red Indicator Powder Pillow and swirl the content of the 250mL Erlenmeyer flask. Finally, add titrant until the color changes to a light pink color (or the pH is 4.5) and calculate testing results.

Summary of method

After adding phenolphthalein indicator and titrating the sample with sulfuric acid solution, the color changes at the endpoint pH of 8.3 that indicates the phenolphthalein alkalinity and measures the total hydroxide and one-half the carbonate in the sample. After adding bromcresol green-methyl red indicator, titration of the sample continues to the second endpoint at pH between 4.3 and 4.9 that indicates the total alkalinity and measures all carbonate, bicarbonate and hydroxide in the sample. The endpoint pH can be determined with test strips or with pH meter.