Dec 02, 2024

Public workspace0.1 M Potassium Phosphate Buffer pH 7.4

DOI
dx.doi.org/10.17504/protocols.io.81wgbr7oylpk/v1
  • 1Walther Straub Institute for Pharmacology and Toxicology, TUM;
  • 2Walther Straub Institute for Pharmacology and Toxicology, LMU Munich
  • Luisa F Jimenez-Soto: Corresponding author (l.jimenez_(at)_lmu.de);
Luisa F Jimenez-Soto
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DOI: dx.doi.org/10.17504/protocols.io.81wgbr7oylpk/v1
Protocol Citation: Christoph Meister, Luisa F Jimenez-Soto 2024. 0.1 M Potassium Phosphate Buffer pH 7.4. protocols.io https://dx.doi.org/10.17504/protocols.io.81wgbr7oylpk/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: November 25, 2024
Last Modified: December 02, 2024
Protocol Integer ID: 112733
Keywords: Potassium Phosphate Buffer, potassium phosphate buffer, buffer, AlamarBlue, potassium phosphate, QC
Abstract
Potassium phosphate buffers, sometimes referred to as "Gomori buffers" are a combination of monobasic dihydrogen phosphate and dibasic monohydrogen phosphate in an aquaeous solution1 . It has a high buffering range, which can be shifted by adjusting the amount of either one of the phosphate salts.1

This buffer is described by Bio-Rad as component required for the Quality Control (QC) check of their AlamarBlue product ( Catalog Nr. BUF012A). For more information on how to use it, check their manual (accessed 2022). Download AlamarBlue_Manual_Biorad.pdfAlamarBlue_Manual_Biorad.pdf509KB


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Exotoxins Lab (CC-BY-SA 4.0)
Guidelines
  • As good microbiological practice, all containers used for components should be labeled with the name of the solution, the date of creation / aliquot, and initials of the person who did it, in order to ask questions if something is needed.
  • If you have doubts about how to perform a step in the protocol, consult your supervisor or someone who has prepared the solution before.
  • For any questions, feel free to email us (exotoxinslab-(at)- gmail.com). We are more than happy to help you.
  • Some of the protocols will be posted in our YouTube channel (www.youtube.com/@exotoxinslab).
Materials
  1. ReagentPotassium phosphate dibasicMerck MilliporeSigma (Sigma-Aldrich)Catalog #1051041000 (mw: 174.18 g/mol)
  2. ReagentPotassium dihydrogen phosphateMerck MilliporeSigma (Sigma-Aldrich)Catalog #1048731000 (mw: 136.09 g/mol)
  3. Reagentdouble distilled water (ddH2O)Contributed by users When using double distilled water, we use only water with equal or less than 0.055 µS/cm.
  4. ReagentPotassium hydroxide (KOH)Merck MilliporeSigma (Sigma-Aldrich)Catalog #484016

Protocol materials
ReagentPotassium phosphate dibasicMerck MilliporeSigma (Sigma-Aldrich)Catalog #1051041000
ReagentPotassium dihydrogen phosphateMerck MilliporeSigma (Sigma-Aldrich)Catalog #1048731000
ReagentPotassium phosphate dibasicMerck MilliporeSigma (Sigma-Aldrich)Catalog #1051041000
ReagentPotassium dihydrogen phosphateMerck MilliporeSigma (Sigma-Aldrich)Catalog #1048731000
Reagentdouble distilled water (ddH2O)
ReagentPotassium hydroxide (KOH)Merck MilliporeSigma (Sigma-Aldrich)Catalog #484016
ReagentPotassium hydroxide (KOH)Merck MilliporeSigma (Sigma-Aldrich)Catalog #484016
Safety warnings
  • Careful: Potassium Hydroxide is a strong base. Use your Protective Personal Equipment when handling this substance.

  • Potassium phosphate buffers inhibit enzymatic reactions by sequestering divalent cations such as calcium and magnesium.1

Before start
  1. Be aware of your lab's safety protocols and check the attached Warnings (Guidelines and Warnings) to see what steps are necessary to protect yourself, such as protocol-appropriate personal protective gear, like lab coat, gloves and glasses.
  2. Make sure to read the whole protocol before starting and have all the materials at hand.
0.1 M Potassium Phosphate Buffer pH 7.4
0.1 M Potassium Phosphate Buffer pH 7.4
Prepare Amount400 mL of dH2O in a measuring cylinder. Add a magnetic mixing rod to the cylinder.

Add Amount6.059 g of ReagentPotassium phosphate dibasicMerck MilliporeSigma (Sigma-Aldrich)Catalog #1051041000 to the water and start to mix using a magnetic plate to move the mixing rod and solution of the substance.

Add Amount2.07 g of ReagentPotassium dihydrogen phosphateMerck MilliporeSigma (Sigma-Aldrich)Catalog #1048731000 to the solution. Keep stirring until both substances have dissolved completely.

Measure the pH. If necessary, use a solution of Concentration1 Molarity (M) ReagentPotassium hydroxide (KOH)Merck MilliporeSigma (Sigma-Aldrich)Catalog #484016 to raise the pH to Ph7.4 . Add distilled H2O until the volume is 0.5 L. Transfer the solution to a bottle and store at room temperature. If needed, it can be sterile filtrated.
Note
We achieved the desired pH of 7,39 by carefully adding to the solution approx. 5 ml of 1 M Potassium Hydroxide under stirring. This value can change depending of your water source and chemicals used. Careful: Potassium Hydroxide is a strong base. Use your Protective Personal Equipment when handling this substance.





Protocol references
https://www.aatbio.com/resources/buffer-preparations-and-recipes/potassium-phosphate-ph-5-8-to-8-0, October 27th, 2022 (accessed November 2024)

https://www.unl.edu/cahoonlab/phosphate%20buffer.pdf (accessed November 2024)