0.1 M Citrate Buffer Preparation
Introduction
Citrate buffer is a commonly used buffer solution in various biochemical and molecular biology applications. It is specifically used to maintain pH and optimize enzymatic reactions. In this article, we will outline the step-by-step procedure for preparing a 0.1 M citrate buffer solution.
Materials
- Sodium citrate dihydrate (C6H5NaO7.2H2O)
- Citric acid monohydrate (C6H8O7.H2O)
- Distilled water
- pH meter
Protocol
Step 1: Prepare Stock Solutions
- Dissolve 29.4 g of sodium citrate dihydrate in 100 mL of distilled water to prepare a 1 M stock solution.
- Dissolve 21.0 g of citric acid monohydrate in 100 mL of distilled water to prepare a 1 M stock solution.
Step 2: Mix Stock Solutions
- Mix 50 mL of the 1 M sodium citrate stock solution with 25.5 mL of the 1 M citric acid stock solution.
- Add distilled water to the mixture to bring the final volume to 100 mL.
Step 3: Adjust pH
- Use a pH meter to measure the pH of the buffer solution.
- Adjust the pH to 4.5, 5.5, or 6.5 by adding small amounts of 1 M citric acid or 1 M sodium citrate stock solutions.
Step 4: Filter and Sterilize
- Filter the buffer solution through a 0.2 μm membrane filter to remove any impurities.
- Sterilize the buffer solution by autoclaving at 121°C for 15 minutes.
Final Solution
The resulting 0.1 M citrate buffer solution is ready to use. The solution can be stored at room temperature for up to 6 months.
Tips and Variations
- The pH of the buffer solution can be adjusted to specific values by varying the ratio of sodium citrate and citric acid.
- The concentration of the buffer solution can be adjusted by changing the amount of distilled water added in Step 2.
- Other buffer solutions, such as phosphate or Tris, can be prepared using similar protocols.
By following this protocol, you should be able to prepare a high-quality 0.1 M citrate buffer solution for your biochemical and molecular biology applications.
