Liquid chromatography/mass spectrometry analysis of mixtures of rhamnolipids produced by Pseudomonas aeruginosa strain 57RP grown on mannitol or naphthalene

Liquid chromatography/mass spectrometry using electrospray ionisation was u sed to analyse rhamnolipids produced by a Pseudodomonas aeruginosa strain w ith mannitol or naphthalene as carbon source. Identification and quantifica tion of 28 different rhamnolipid congeners was accomplished using a reverse -phase C-18 column and a 30 min chromatographic run. Isomeric rhamnolipids that were not chromatographically resolved could be identified by interpret ation of their mass spectra and their relative proportions estimated. The m ost abundant rhamnolipid produced on mannitol contained two rhamnoses and t wo 3-hydroxydecanoic acid groups. The most abundant rhamnolipid produced fr om naphthalene contained two rhamnoses and one 3-hydroxydecanoic acid group . (C) 1999 Elsevier Science B.V. All rights reserved.