A novel dispersive liquid–liquid microextraction (DLLME) gas chromatography-mass spectrometry (GC–MS) method for the determination of eighteen biogenic amines in beer

A novel dispersive liquid–liquid microextraction (DLLME) gas chromatography mass-spectrometry (GC–MS) method was developed for the determination of 18 biogenic amines in beers. The method features the simultaneous extraction/derivatization of the amines providing a simple and fast mode of extract enrichment. A mixture of acetonitrile (dispersive solvent; 1.0 mL), toluene (extractive solvent; 325 μL), and isobutyl choloroformate (derivatizing reagent; 25 μL) was used as extractive/derivatizing reagent, added to 5 mL of sample. The proposed method showed good linearity (correlation coefficients > 0.997), good recoveries (from 72 to 113%), and good intra-day precision (below 13%) and inter-day precision (below 14%). Moreover, detection limits were never over 2.9 μg L−1. The developed method was successfully applied to the analysis of 22 beer samples commercialized in Portugal. Fourteen of the eighteen biogenic amines analyzed were found in most of the beers, with predominance of putrescine, tyramine, dimethylamine, cadaverine, pyrrolidine and 1,3-diaminopropane.