Characterization of recalcitrant intermediates from biotransformation of the branched alkyl side chain of nonylphenol ethoxylate surfactants

Experiments on the ultimate fate of nonylphenol polyethoxylates (A9PEs) shows that more extensively alkyl branched A9PE chains disappeared after three months while a more persistent A9PECs with both side chains oxidized (CAPEC) remain. Tests used chromatography-electrospray-mass spectrometry to elucidate structures produced and finds that the resulting CAPECs were extremely recalcitrant to further biotransformation and that they amounted to 63% of the total A9PE metabolites remaining.