Improved positive electrospray ionization of patulin by adduct formation: usefulness in liquid chromatography-tandem mass spectrometry multi-mycotoxin analysis.

Several sensitive methods have been developed for patulin determination; however, mass spectrometric (MS) detection of this toxin in the positive electrospray ionization (ESI(+)) mode is not straightforward. Furthermore, the combined determination of patulin with other mycotoxins in one single run has not been reported yet. The present paper demonstrates the formation and use of a methanol adduct of patulin in ESI(+). A study of the fragmentation pathway confirmed the authenticity of the patulin adduct, while the use of ion trap and high resolution Orbitrap mass spectrometry allowed reliable assignment of the patulin fragment ions. Exploiting the formation of the methanol adduct, patulin has been successfully included in a single run multi-mycotoxin liquid chromatography tandem mass spectrometric (LC-MS/MS) method in support of ex vivo-in vitro biomedical studies.