Microextraction of bacterial lipid A: easy and rapid method for mass spectrometric characterization

J Lipid Res. 2005 Aug;46(8):1773-8. doi: 10.1194/jlr.D500014-JLR200. Epub 2005 Jun 1.


Endotoxins (lipopolysaccharides) are the main components of Gram-negative bacterial outer membranes. A quick and simple way to isolate their lipid region (lipid A) directly from whole bacterial cells was devised. This method using hot ammonium-isobutyrate solvent was applied to small quantities of cells and proved to be indispensable when a rapid characterization of lipid A structure by mass spectrometry was required. Biological activities of endotoxins are directly related to the lipid A structures, which vary greatly with cell growth conditions. This method is suitable for rough- and smooth-type bacteria and very efficient for screening variations in lipid A structures. Data are acquired in a few hours and avoid the use of phenol in extraction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Butyrates
  • Gram-Negative Bacteria / chemistry
  • Isobutyrates
  • Lipid A / chemistry
  • Lipid A / isolation & purification*
  • Mass Spectrometry
  • Methods
  • Molecular Structure


  • Butyrates
  • Isobutyrates
  • Lipid A
  • isobutyric acid