What are some common interferences in the alkalinity titration methods?
Interferences in alkalinity titration methods
Some common interferences in alkalinity titration methods include:
- Chlorine: Chlorine at levels above 3.5 mg/L can cause a yellow-brown color when the Bromcresol Green-Methyl Red Powder Pillow is added. To remove the interference, pretreat the sample by adding 1 drop of Sodium Thiosulfate Standard Solution, 0.1N, 100 mL MDB Product # 32332 per 100 mL sample, before adding any other reagents.
- Color or turbidity: Color or turbidity can make it difficult to see the color change at the endpoint. Do not filter or dilute samples with color or turbidity. Use a pH meter and titrate the samples to the specified endpoints:
- Soaps, oily matter, suspended solids, and precipitates: Oils or solids can collect on the pH probe and cause a slow response. Clean the probe immediately after use.