This document specifies a method for the quantitative determination of pyrrolizidine alkaloids (PA) in the concentration ranges shown in Table 1 in complete and supplementary feed and in forages by liquid chromatography tandem mass spectrometry (LC-MS/MS) after solid phase extraction (SPE) clean-up. Table 1 - Summary of concentration ranges per PA tested in the collaborative trial NOTE 1 A second method was part of the method validation collaborative main trial. For this method PA-N-Oxides are reduced by adding zinc powder to the extract of the feed material. The following steps correspond to the first and main method. Quantitative results for each PA except the otonecine type PA senkirkine represent the sum of the free PA base and its corresponding N-oxide. NOTE 2 Due to insufficient numbers of data for some analyte-matrix combinations statistical evaluation was not valid for standardization. Received data indicated the methods applicability in experienced laboratories with appropriate quality assurance measures. Therefore, the method description is included as an informative annex (Annex D).