Introduction

Phosphate Buffered Saline (PBS) is a versatile and essential solution used widely in biological research and routine laboratory work. It maintains a constant pH level, serves as a physiological isotonic solution, and can be used in various applications such as cell culture, molecular biology, and immunoassays. Making your own PBS is simple and cost-effective. In this article, we will discuss three different ways to prepare PBS for your specific requirements.

1. Prepare 10X Stock Solution

A 10x stock solution will allow you to create smaller volumes of working 1x PBS by simply diluting the stock solution with distilled water. To make a 10x PBS stock solution, follow these steps:

Ingredients:

– Sodium chloride (NaCl): 80 g

– Potassium chloride (KCl): 2 g

– Sodium phosphate dibasic (Na2HPO4): 14.4 g

– Potassium phosphate monobasic (KH2PO4): 2.4 g

– Distilled water: Up to 1 L

Procedure:

1. Weigh each of the four salts accurately.

2. Dissolve the salts in around 800 mL of distilled water.

3. Adjust the pH to 7.4 using either hydrochloric acid (HCl) or sodium hydroxide (NaOH).

4. Make up the volume to exactly 1 L with distilled water.

5. Sterilize the solution through a filter capable of removing particles of size below 0.22 µm.

6. Store the stock solution at room temperature.

To make working strength PBS from your 10x stock, dilute it at a ratio of 1:9 with distilled water.

2. Directly Prepare Working Solution at Desired Concentration

Ingredients for preparing a working strength (1x) PBS solution:

– Sodium chloride (NaCl): 8 g

– Potassium chloride (KCl): 0.2 g

– Sodium phosphate dibasic (Na2HPO4): 1.44 g

– Potassium phosphate monobasic (KH2PO4): 0.24 g

– Distilled water: Up to 1 L

Procedure:

1. Follow the same steps as the previous method, but dissolve the salt quantities for a 1x solution directly in 1 L of distilled water.

2. Adjust the pH to 7.4, sterilize through a filter and store at room temperature.

3. Purchase a Commercial PBS Solution or Powder

If you don’t have access to individual salts or if you wish to save time, commercial PBS solutions and powders are widely available from laboratory suppliers. Follow the manufacturer’s instructions on how to prepare the PBS from the powder or ready-to-use solutions.

Conclusion

These three methods will help you make Phosphate Buffered Saline for your laboratory tasks. It is up to you which method to choose, depending on your available resources, time, and specific requirements. Once prepared, remember to store your final PBS solution at room temperature and check its quality and sterility before using it in your experiments.