Determination of biogenic amines in coffee by an optimized liquid chromatographic method

An high-performance liquid chromatography (HPLC) method is described for specific and sensitive quantification of seven biogenic amines in coffee (putrescine, cadaverine, histamine, serotonine, tyramine, spermidine, and spermine). They are extracted from the coffee matrix with trichloroacetic acid, followed by an ion-pair clean-up procedure with bis-2-ethylhexylphosphate. Finally, they are converted to the corresponding dansyl derivatives for HPLC analysis. The factors that influence the determination were carefully adjusted according to coffee matrix characteristics (extraction, clean-up, and derivatization conditions). Chromatographic separation is performed in a Kromasil C-18 column, using a 0.5 mM phosphoric acid/acetonitrile/ methanol gradient, at a flow rate of 1 mL/min. The effluent is monitored by a series arrangement of a diode-array detector followed by a fluorimetric detector. The present analytical method proved to be accurate, linear, and with lower limits of quantification (less than 0.5 mg/kg). Data concerning recovery and repeatability of the method are also reported.