Determination of calcium ions:
complexometric/colorimetric titration
Procedure
- Collect 10 mL of the water to be analyzed and transfer it to a 25 mL beaker.
- Add 3 mL of pH 12 buffer solution under an extraction hood and a spatula tip of CAL. The solution takes on a red-purple color.
- Titrate the solution with EDTA at 10-2 mol/L while vigorously stirring the solution.
- The equivalence point is reached when the red-purple color disappears favor of the blue color of CAL released in the solution.
≈ 20 minutes / sample
