0.1 M Borate Buffer pH 8.5 Recipe
Introduction
Borate buffer is a commonly used buffer solution in various biological and biochemical applications. It is particularly useful in maintaining a stable pH during enzymatic reactions, protein purifications, and other laboratory procedures. In this article, we will provide a recipe for preparing 0.1 M borate buffer with a pH of 8.5.
Recipe
Materials
- Borax (Na2B4O7·10H2O)
- Boric acid (H3BO3)
- Sodium hydroxide (NaOH)
- Distilled water
- pH meter
Instructions
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Prepare a stock solution of borax: Weigh 38.14 g of borax and dissolve it in 1 liter of distilled water.
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Prepare a stock solution of boric acid: Weigh 6.18 g of boric acid and dissolve it in 1 liter of distilled water.
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Calculate the amount of borax and boric acid required: To prepare 0.1 M borate buffer with a pH of 8.5, you will need to mix the two stock solutions in a specific ratio. The required amount of borax and boric acid can be calculated using the following formulae:
- Borax: ( Volume of buffer required (L) x Molarity (0.1 M) x Molecular weight of borax (381.4 g/mol) ) / 1000
- Boric acid: ( Volume of buffer required (L) x Molarity (0.1 M) x Molecular weight of boric acid (61.83 g/mol) ) / 1000
For example, to prepare 1 liter of 0.1 M borate buffer with a pH of 8.5, you will need:
- Borax: (1 L x 0.1 M x 381.4 g/mol) / 1000 = 38.14 g
- Boric acid: (1 L x 0.1 M x 61.83 g/mol) / 1000 = 6.18 g
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Mix the stock solutions: Add the calculated amount of boric acid stock solution to the borax stock solution and mix well.
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Adjust the pH: Using a pH meter, adjust the pH of the buffer solution to 8.5 by adding sodium hydroxide (NaOH) or hydrochloric acid (HCl) as needed.
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Filter and store: Filter the buffer solution through a 0.2 μm filter and store it at room temperature for up to 6 months.
Tips and Precautions
- Use high-quality reagents and distilled water to prevent contamination and ensure accurate pH measurement.
- Handle the buffer solution with care to avoid mixing with air, which can affect the pH.
- Store the buffer solution in a clean, airtight container to prevent degradation.
- Before using the buffer solution, always check its pH and adjust it if necessary.
By following this recipe, you should be able to prepare a high-quality 0.1 M borate buffer with a pH of 8.5 for your laboratory applications.
