Combined ion-pair extraction and gas chromatography–mass spectrometry for the simultaneous determination of diamines, polyamines and aromatic amines in Port wine and grape juice

Abstract

An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (β-phenylethylamine and tyramine) found in Port wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC–MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the aminoacids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [ 2H 8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 μg l −1. The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white table wines. Results are presented and briefly discussed.