Novel and sensitive method for the detection of anandamide by the use of its dansyl derivative

The dansyl ester of anandamide was prepared and showed intense fluorescence on silica gel thin-layer chromatography when viewed under long-wavelength ultraviolet light (detection limit, 15 fmol). A high-performance liquid chromatography method for the quantitation of anandamide was developed using a C18 column (250×4.6 mm) with gradient elution (1% acetic acid–methanol) and detection at 255 nm. The method was applied to the measurement of anandamide in media from cultured hepatocytes. Sample preparation involved extraction with a C18 cartridge, derivatization with dansyl chloride, thin-layer chromatography, and quantitation. The detection limit in hepatocyte media is 4.3 nmol at a signal-to-noise ratio of three.