Inter-laboratory comparison study for pyrrolizidine alkaloids in animal feed using spiked and incurred material

Abstract

Pyrrolizidine alkaloids (PAs) are hepatotoxic metabolites produced by plants. PAs in animal feed can cause acute or chronic intoxications in animals and can be transferred to milk. An inter-laboratory comparison study among 12 laboratories, using their own methods of analysis, was conducted for the detection and quantification of PAs in animal feed. The participants were asked to quantify PAs in a blank test sample, a blank test sample to be spiked with a provided spiking mixture of seven PA standards, and a test sample contaminated with common groundsel (Senecio vulgaris). Ten of the participating laboratories used an LC-MS/MS method, one used an LC-ToF-MS method, and one used a GC-MS method. None of the laboratories reported false-negative samples, while two laboratories reported false-positive results in the blank sample. z-scores were calculated for each laboratory for seven PAs in test samples B and C. z-scores varied considerably between laboratories for the concentrations of the free bases and less for the N-oxides, probably due to the lower levels of the free bases as compared with the N-oxides in the contaminated feed. Questionable or unsatisfactory results for the z-scores were obtained for 8% of the cases for the spiked sample and for 12% of the incurred sample. Three laboratories scored consequently positive or negative results. No preferred method for quantification of PAs in feed could be identified within the methods used for this study due to the relatively small number of participants. It was concluded that this inter-laboratory study shows that the methods used for PA detection need further development for accurate estimation of PAs in contaminated feed.

UPLC–MS/MS method for determination of selected pyrrolizidine alkaloids in feed

“…2). The LOQs provided by our method are comparable to those reported in literature (De Nijs, Elbers, & Mulder, 2014;Martinello et al, 2014). Although there are studies (Zhou et al, 2010) which present methods with lower LOQs they are not dedicated to multi-class as well as a multi-matrix approach.…”

Occurrence of pyrrolizidine alkaloids in animal- and plant-derived food: results of a survey across Europe

“…In contrast to rooibos tea, where seneciphylline and its N-oxide were minor compounds, these PAs -together with senecionine N-oxide -were the major compounds present in peppermint tea. The PA pattern in peppermint tea bears a strong resemblance to that of Senecio vulgaris, a common weed of arable areas in the moderate climate zone (de Nijs et al 2014). The PA pattern in camomile tea is complex, showing contributions of senecionine-, lycopsamine-, and heliotrine-type PAs (Figure 3(e)) and suggesting production areas from different geographical regions.…”

Occurrence of Pyrrolizidine Alkaloids in food

“…Plants of Senecio species seem to be the most important with respect to contamination of peppermint teas, although Heliotropium and species of the Boraginaceae family, may contribute to a smaller amount as well. The PA pattern found for the senecionine-type PAs correlates particularly well to that of Senecio vulgaris (common groundsel) (Mulder et al, 2009;de Nijs et al, 2014). The present document has been produced and adopted by the bodies identified above as author(s).…”