Carbonyl photoproducts from solar irradiated oil films on seawater

Thin films of Macondo source oil (provided by BP), surrogate oil (provided by BP), and residual fuel oil (NIST SRM 2171a) were individually exposed to simulated sunlight. After exposure, the aqueous phase was derivatized with 2,4-dinitrophenylhydrazine (DNPH), which selectively reacts with aldehydes and ketones. After a clean up step, derivatized samples were analyzed by electrospray-MS-MS (negative ion mode) and characteristic fragmentation patterns were used to identify derivatized aldehyde and ketones. Comparison to dark controls and irradiated seawater (no oil) allowed identification of products that were unique to the irradiated samples.