Determination of oligomer distribution of alkylphenol polyethoxylates and fatty alcohol polyethoxylates by positive-ion atmospheric pressure chemical ionization mass spectrometry

Abstract

Positive-ion atmospheric pressure chemical ionization mass spectrometry was used to analyse commercial alkylphenol polyethoxylates and fatty alcohol polyethoxylates. The mass spectra show oligomer distributions with respect to (1) the degree of ethoxylation of each alkyl base and (2) different alkyl bases. Polyglycol ether and its molecular mass distribution could be identified from the mass spectra for all the surfactant samples tested. Relative amounts of each oligomer present in the sample could be calculated by scanning the sample at appropriate masses (selected ion monitoring mode). Mass-average molecular masses of each polymer series could therefore be calculated