Biological Buffers


Synonym: 3-Morpholinopropane-1-sulfonic acid, 3-(N-Morpholino)propanesulfonic acid and 3-Morpholinopropanesulfonic acid

The zwitterionic buffer MOPS is a structural analog to MES, one of the Good's buffers that were developed for general use in biochemistry. MOPS is primarily used as a buffer for the separation of RNA in agarose gels2.
Useful pH Range 6.5 - 7.9
Working concentration range 20mM-1M7, 8


        Comparison of products by grade or quality level
Name CAS Molecular Formula Mol Wt Reagent Grades Life Science Grades PharmaGrade  Solutions
MOPS 1132-61-2 C7H15NO4S 209.26 6310-OP M1254 RDD003 M3183 M5162 69947 PHG0007 M1442
MOPS sodium salt 71119-22-7 C7H14NNaO4S 231.25 M9381 RDD018 475889 M5789 M9024 RES0197M-A7  
MOPS hemisodium salt 117961-20-3 C7H14.5NO4S • 0.5Na 220.25 M0289 M9027      


Interaction Comments

MOPS interferes with the Folin protein assay5
Solutions of MOPS are not completely stable when autoclaved in the presence of glucose.1
Usage above 20 mM in mammalian cell culture work is not recommended4
MOPS stabilizes BSA3
Strong interaction with Fe; weak interaction with Mg, Mn, Co and Ni6



  1. The Merck Index, 12th ed., Entry# 6346. 1996
  2. Molecular Cloning: A Laboratory Manual, 3rd ed., Sambrook, J. and Russell, D.W., CSHL Press (Cold Spring Harbor, NY: 2001), p. 7.32.
  3. Taha, Mohamed. et al. 2011. Macromolecules. 44.21: 8575-8589.
  4. Eagle, H., Science, 174, 500-503 (1971).
  5. Ferguson, W.J. et al. (1980) Anal. Biochem. 104, 300-310 Hydrogen ion buffers for biological research.
  6. Ferreira CM, Pinto IS, Soares, EV, Soares HM. 2015 Royal Society of Chemistry 30989- 31003
  7. Downs SM, Mastropolo AM, Culture Conditions Affect Meiotic Regulation in Cumulus Cell-Enclosed Mouse Oocytes, Molecular Reproduction and Development 1997(46) 551-566
  8. Gupta B, Taha M, Lee M-J, Buffers more than buffering agent: introducing a new class of stabilizers for the protein BSA, Phys. Chem. Chem. Phys 2015(17) pp 1114-1133