Preparation of SM buffer (lambda diluent)

SM buffer is primarily used in biology laboratories, and its main function, like any other buffer, is to stabilize the pH. That is, it can withstand minor pH changes, increasing the stability of biological materials or molecules. When performing an experimental task, it is critical to keep all other variables constant and only vary the tested variables. This emphasizes the significance of keeping the pH stable through reliable and consistent methods such as buffer systems. SM buffer is one of them and is used for routine phage suspension manipulation. You can make SM buffer with or without gelatin. During storage, the gelatin in the SM buffer stabilizes phage particles.

SM buffer container-preparation of SM buffer

Preparation of SM Buffer

Content

SM Buffer Recipe Table
Reagent Amount Final Concentration
NaCl 5.8 g 100 mM
MgSO4·7H2O 2 g 8 mM
Tris-Cl (1 M, pH 7.5) 50 ml 50 mM
Gelatin (2%, w/v) 5 ml 0.01% (w/v)
H2O to 1 litre

This recipe is for making one litre. If you need a different volume, use our SM Buffer calculator.

Procedure

To prepare 1 litre of SM buffer with gelatin, 

  1. Dissolve the NaCl and MgSO4·7H2O in 800 ml of H2O; 
  2. Add the Tris-Cl and gelatin,
  3. Adjust the volume to 1 litre with H2O. 
  4. Sterilize the buffer by autoclaving for 20 minutes at 15 psi (1.05 kg/cm2) on a liquid cycle. 
  5. After the solution has cooled, dispense 50 ml aliquots into sterile containers.

Storage condition

SM buffer with gelatin may be stored indefinitely at room temperature

NOTE: Discard each aliquot after use to minimize the chance of contamination

To prepare SM Buffer without gelatin click here and to prepare Tris-cl click here

About the author

Hello there!

I'm Raphael Hans Lwesya. I have a deep interest in phage research and science communication. I strive to simplify complex ideas and present the latest phage-related research in an easy-to-digest format. Thank you for visiting The Phage blog. If you have any questions or suggestions, please feel free to leave a comment or contact me at [email protected].
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