2448200 Calcium and Total Hardness Reagent Set, Buret, 0-25000 mg/L CaCO₃

Article 2448200 measures calcium and total hardness in the range of 0-25000 mg/L CaCO₃ in water, wastewater and seawater. Calcium and Total Hardness Reagent Set uses EDTA Titration method (8338).

Calcium and Total Hardness Reagent Set includes:

• Hardness 1 Buffer Solution (p/n 42432)
• CalVer 2 Calcium Indicator Powder Pillows (p/n 94799)
• ManVer 2 Hardness Indicator Powder Pillows (p/n 92899)
• Potassium Hydroxide Standard Solution, 8.00 N (p/n 28232H)
• Sulfuric Acid Standard Solution, 5.25 N (p/n 244932)
• TitraVer Hardness Titrant, 0.020 N (p/n 20553)

Before you start take into account the following:

• Collect the sample in glass or plastic containers cleaned with detergent and rinsed with 1:1 nitric acid and deionized water.
• Adjust the pH to 7 with Potassium Hydroxide Standard Solution before sample analysis.
• Correct the testing results for the dilution caused by the volume additions.

Procedure for CaCO₃ measurement

Select the appropriate sample volume and choose the titration cartridge from the table in the working procedure description. Fill 25-mL buret to the with the titrant. Transfer the sample into 250-mL Erlenmeyer flask. Pipet 1 mL of 8 N Potassium Hydroxide Standard Solution and swirl the content of the Erlenmeyer flask. Add CalVer 2 Calcium Indicator Powder Pillow and swirl to mix. Add titrant until the color changes from red to pure blue and calculate the concentration. Add 5.25 N Sulfuric Acid Standard Solution, until the color changes from pure blue to purple and then to red. Pipet 1 mL of Hardness 1 Buffer Solution and swirl the Erlenmeyer flask. Pour the content of ManVer 2 Hardness Indicator Powder Pillow and swirl to mix. Place the flask under the buret, swirl the Erlenmeyer flask and continue adding titrant until the color changes from red to pure blue. Calculate the concentration (see manual for detailed information regarding calculation of the testing results).

Summary of method

This test procedure is a combination of the calcium and total hardness procedures. Refer to each method for more information. 

Sample preparation

For 6 month storage of the sample, it is required to reduce the sample pH to 2 or less with concentrated nitric acid. Store the conserved sample at or below 6 °C (43 °F).