Electrospray Mass Spectrometric Analysis and Photocatalytic Degradation of Polyethoxylate Surfactants Used in Wool Scouring

Electrospray mass spectrometry (ESMS) has been used to identify the mixture of components in three nonionic surfactants, nonylphenol ethoxylate (NPE), secondary alcohol ethoxylate (SAE), and primary alcohol ethoxylate (PAE). In each case singly protonated species are observed with the number of ethylene oxide units ranging from 4 to 16. Collisionally activated decomposition of protonated SAE leads to cleavage of the secondary carbon-oxygen bond to give protonated ethylene oxide fragment ions. ESMS is used to show that the products of the photocatalytic decomposition of SAE are the same as those produced by the collisionally activated decompositions. The surfactants can also be singly ionised in solution by addition of sodium or potassium ions, and the products observed by ESMS.