Disclosed herein are methods useful for detecting and/or quantifying tropolone in samples, e.g., generated during the production of and in final formulations of a product, e.g., a recombinant protein, e.g., an antibody. Tropolone and derivatives thereof (cycloheptatriene ketones) are separated from a mixture by adding a partially or fully fluorinated alkyl or aryl (e.g. pentafluorophenyl-propyl), which (covalently) binds the tropolone-like compound. Then it is assayed via UV or tandem mass spectrometry. A reaction mixture of tropolone-like compounds and fluorinated alkyl or aryl is also disclosed.