Polyether surfactants were analyzed using liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESIMS) with a C18 reversed-phase column and a solvent system containing MeOH/H2O at a flow rate of 500L/min. Operating in the positive-ion mode over m/z 100900, the sodium and/or proton adduct ions were generated in the ESI interface for alcohol, alkylphenol and amide ethoxylates. MS studies show that conventional RP-HPLC can affect the resolution of most polyether surfactants on the basis of alkyl chain length. Usually, each peak represents a single alkyl chain length but the whole distribution of ethoxy chain lengths with larger alkyl homologs eluting after the smaller ones. Coupled with MS analysis of each peak, a relatively simple RP-HPLC separation is enough to characterize many mixtures of polyether surfactants. © 2003 Elsevier Science B.V. All rights reserved.