Determination of the Fusarium mycotoxins, fusaproliferin and beauvericin by high-performance liquid chromatography-electrospray ionization mass spectrometry

A method is described using LC-MS for the detection of the mycotoxins fusap roliferin (FUS) and beauvericin (BEA) in cultures of Fusarium subglutinans and in naturally contaminated maize. Protonated molecular ion signals for F US and BEA were observed at m/z 445 and m/z 784, respectively. Collision in duced dissociation of the readily dehydrated protonated molecular ion of th e sesterterpene FUS (m/z 427) led to the loss of another water molecule (m/ z 409) and acetic acid (m/z 385), while the cyclic lactone trimer BEA fragm ented to yield the protonated dimer (m/z 523) and monomer (m/z 262), respec tively. Detection of FUS was best performed in the MS-MS mode while BEA dis played a stronger signal in the MS mode. The on-column instrumental detecti on limits for pure FUS and BEA were found to be 2 ng and 20 pg (S/N = 2) wh ile those in naturally contaminated maize were 1 mu g/kg and 0.5 mu g/kg, r espectively. Five South African strains of F. subglutinans were analyzed fo llowing methanol extraction of which four produced FUS at levels between 33 0 mg/kg and 2630 mg/kg while only three produced BEA at levels between 140 mg/kg and 700 mg/kg. Application of this method to naturally contaminated m aize samples from the Transkei region of South Africa showed FUS at levels of 8.8-39.6 mu g/kg and BEA at 7.6-238.8 mu g/kg. (C) 1999 Elsevier Science B.V. All rights reserved.