High performance liquid chromatography/tandem mass spectrometry determination of biogenic amines in typical Piedmont cheeses.

The paper presents a new HPLC method, hyphenated with mass spectrometry detection, for the separation and determination of the biogenic amines that are most commonly present in cheese, namely cadaverine, histamine, spermidine, spermine, tyramine and tryptamine. The HPLC-MS/MS method is validated by comparison of the results with those obtained through a literature HPLC-UV determination, based on a pre-column dansyl chloride derivatisation step. The intercalibration is based on the statistical t-test for multiple samples that allows to compare simultaneously the results obtained with the two methods for more analytes and to decide, at a prefixed confidence level, if the two methods are inter-changeable. The new HPLC-MS/MS method, employed in selected reaction monitoring (SRM) mode, permits to achieve for standard solutions limit of detection (LOD) values ranging from 1.7 to 22.5 microg L(-1) and LOQ (limit of quantitation) values ranging from 5.6 to 68.2 microg L(-1). In order to apply the method in the analysis of cheeses, LOD and LOQ values have also been evaluated in "ricotta" cheese, in order to take as possible into account the matrix interference. In these conditions LODs range between 5.1 and 35.0 microg L(-1) and LOQs between 14.2 and 101.2 microg L(-1). The whole methodology, comprehensive of the homogenization-extraction process and HPLC-MS/MS analysis, has been applied in the analysis of three typical Piedmont (North-West Italy) cheeses, known as Toma Piemontese, Raschera and Castelmagno.