Small amounts of dilute HCl and/or NaOH to pH the final solution 800 mL of distilled water 8 g of NaCl (sodium chloride) 0. 2 g of KCl (potassium chloride) 1. 44 g of Na2HPO4 (disodium phosphate) 0. 24 g of KH2PO4 (monopotassium phosphate) The final concentrations of each compound should be 137 mm NaCl, 10 mM Na2HPO4, 1. 8 mM KH2PO4, 2. 7 mM KCl, and a pH 7. 4. [2] X Research source
A stir bar contains a magnet that allows the bar to spin and stir the solution when a container of liquid is placed on the stir plate, which contains a motor. [4] X Research source Wait until there is solution in the beaker before turning it on.
With the water in the beaker, turn on the stir plate to a medium speed. You should see a small whirlpool form in the water as the stir bar begins to spin.
If you add too much of a chemical, simply remove the excess until you have the right amount.
You can let this sit while you do something else and check on it later. It will take at least 5-10 minutes to dissolve.
Use a small pipette to add NaOH a few drops at a time. After each addition, let the solution stir for a moment and check the new reading on the pH meter. Adjusting the pH a solution is a process that requires patience. If you accidentally go higher than 7. 4, you can add a few drops of hydrochloric acid (HCl) to bring it back down.
Pour the final solution into a 1-L glass bottle safe for autoclaving.
Set the autoclave to sterilize for 20 minutes at 15 psi on the liquid cycle. [11] X Research source Autoclave tape has a temperature indicator in it. If the autoclave tape doesn’t turn black when the process is done, the autoclave did not get hot enough and you will need to re-sterilize.
You can also aliquot the PBS into smaller containers to use one at a time.
700 mL of distilled water 80 g of NaCl (sodium chloride) 2 g of KCl (potassium chloride) 14. 4 g of Na2HPO4 (disodium phosphate) 2. 4 g of KH2PO4 (monopotassium phosphate) You will also need small amounts of HCl and/or NaOH to pH the final solution. The final concentrations of each compound in the 10X solution are 1. 37 M NaCl, 27 mM KCl, 100 mM Na2HPO4, and 18 mM KH2PO4.
Wait until there is solution in the beaker before turning the stir plate on.
Once water is added, turn on the stir plate to a medium speed. You should see a small whirlpool form in the water as the stir bar begins to spin.
If you add too much of a chemical, simply remove the excess until you have the right amount.
It will take at least 5-10 minutes to dissolve, so let it stir and check on it later.
Use a small pipette to add NaOH a few drops at a time. After each addition, let the solution stir for a moment and wait until the numbers stop moving. Keep adding NaOH until you reach 7. 4. To pH a solution is a process that requires patience. If you accidentally go higher than 7. 4 you can add a few drops of hydrochloric acid (HCl) to bring it back down.
Pour the final solution into a 1-L glass bottle safe for autoclaving.
Set the autoclave to sterilize for 20 minutes at 15 psi on the liquid cycle. [22] X Research source Autoclave tape has a temperature indicator in it. If it reaches the proper temperature, the tape will turn black. If the tape does not turn black, the autoclave did not get hot enough and you will need to re-sterilize.
You can also aliquot the PBS into smaller containers to use one at a time.
If you just need an aliquot of 1X stock to have around, make around 500 mL. You can use this 1X stock for a while and won’t have to make it as often.
For example: If you want 500 mL of solution, divide 500 by 10 and you get 50 mL. You need 50 mL of 10X stock to make 500 mL of 1X. For example: If you want 2 L of solution, divide 2/10 and you get 0. 2 L. You can convert this to mL by multiplying by 1000. You need 200 mL of 10X stock to make 2 L of 1X.
For example: To make 500 mLs, you need 50 mLs of 10X stock. Since 500 – 50 = 450, you need 450 mL of distilled water to dilute the stock.
For example, add 50 mL of 10X stock to 450 mL of distilled water to make 1X PBS stock. Swirl the container to mix the solution.
Use the pH meter to measure the pH and use HCl or NaOH to correct the buffer to a pH of 7. 4.
