Electrospray ionization tandem quadrupole mass spectrometry for the characterization and identification of ethoxylated surfactants

Electrospray ionization tandem quadrupole mass spectrometry (ESI-MS/MS) has been used for the analysis of non-ionic ethoxylated surfactants. In the present paper a state-of-the-art analytical method for the unambiguous identification and structure elucidation of different alkoxylated fatty acids, alcohols, amines and amides is described. The analysis can be performed using complex mixtures of various surfactants without a prior separation step and, as very characteristic fragment ions can be observed, analysts obtain satisfactory information on both the length and chemical structure of the alkyl chain and alkoxy unit. Even isomerism can be easily recognized and in the case of copolymers it is possible to deduce whether the surfactant has been manufactured by block or random co-polymerization.