Several trifluoromethanesulfonates of general structure ArCOCH2OTf were prepared and their suitability for use as derivatizing agents for the HPLC analysis of betaines was assessed. Four of them (Ar = 2′-naphthyl, 2′-fluorenyl, 6′-methoxynaphthacyl, and 2′-phenanthrenacyl) showed promise for use with UV and/or fluorescence detectors, with the last potentially the most promising.