Patulin is a mycotoxin produced by several fungal species, mainly by Penicillium spp. and Aspergillus spp. Since patulin-producing fungi are widely spread, this toxin has been detected in food (fruit- and vegetable-based products, cereal products, cheese), feed and even in mouldy water-damaged dwellings. Co-occurrence of patulin with other mycotoxins has also been reported [1]. Patulin is commonly analyzed by liquid chromatography with UV detection. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) is considered as a more specific tool for mycotoxin detection and confirmation. However, the implementation of this technique for the determination of patulin, especially in the context of multi-mycotoxin analysis, is limited due to ionization problems.
In this study, the effect of different solvents, mobile phase additives and pH on the ionization and fragmentation pattern of patulin was investigated. The preliminary results showed that under alkaline conditions and using methanol as organic modifier, an intense and stable signal for the methanol-adduct of patulin was obtained in the positive electrospray ionization mode. The fragmentation of this protonated methanol-adduct gave a strong and stable product ion signal. The production spectra were overall more useful than those obtained with the protonated or the deprotonated molecule. These findings indicate the possibility of using the protonated methanol-adduct of patulin for its identification and quantification by LC-MS/MS.
Further results that will be presented include the optimization, by means of experimental design, of the parameters that have an influence on the formation of the protonated methanol-adduct of patulin and on its fragmentation behaviour, as well as the inclusion of this toxin in a multi-mycotoxin LC-MS/MS method. This study is the first report of the LC-MS/MS determination of patulin using its protonated methanol-adduct.
References:
[1] Nielsen KF (2003) Mycotoxin production by indoor molds. Fungal Genetics and Biology. 39: 103-117
