Improved method for the determination of biogenic amines and polyamines in vegetable products by ion-pair high-performance liquid chromatography

Here, we report on the optimisation and validation of a liquid chromatographic method for the determination of 12 biologically active amines from vegetal food products in a single 40-min run. The suitability of the method was checked in five vegetal products of distinct matrix: spinach (leaves), hazelnut (high protein and fat content), banana, potato (high starch content), and milk chocolate (processed). Sample preparation consisted of a 0.6 M perchloric acid extraction from a minced homogeneous aliquot. For samples with high starch content, a previous mild hydrolytic treatment was required to prevent gel formation. The range of linearity was from 0.1 to 10 mg/l, except for serotonin and spermine (from 0.5 to 10 mg/l), and the correlation coefficient was higher than 0.997 (P < 0.001) for all standard curves. The detection limits and the determination limit were below 0.07 and 0.2 mg/l, respectively, except for spermine, which was 0.14 and 0.4 mg/l. The precision of the method was satisfactory; the relative standard deviation obtained for each amine in each product was acceptable according to Horwitz. Recovery was between 77 and 110% for all amines, irrespective of the product.