Abstract
In order to investigate the oxidative biodegradation mechanisms of octylphenol polyethoxylate (OPEO) by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS), fundamental conditions for the bacterial biodegradation test method using 18O-labelled water as an incubation medium were examined. Since 18O-labelled water is a valuable reagent, reduction of incubation medium down to 200 µL could be achieved. Furthermore, to recover OPEO degradation intermediates from a minimum amount of the medium containing basal salt, a simple solid-liquid extraction procedure was introduced. The combination of the biodegradation test using 18O-labelled water and MALDI-MS measurement thus could provide a conclusive biodegradation mechanism by the observation of incorporation of 18O atoms into the carboxyl group of OPEC during the biodegradation process.
