Department of Applied Chemistry, University of Debrecen, Debrecen, Hungary.
Rapid Commun Mass Spectrom. 2013 Feb 28;27(4):553-9. doi: 10.1002/rcm.6482.
The aflatoxin mycotoxins are particularly hazardous to health when present in food. Therefore, from an analytical point of view, knowledge of their mass spectrometric properties is essential. The aim of the present study was to describe the collision-induced dissociation behavior of the four most common aflatoxins: B1, B2, G1 and G2.
Protonated aflatoxins were produced using atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) combined with high-performance liquid chromatography (HPLC). For the tandem mass spectrometry (MS/MS) experiments nitrogen was used as the collision gas and the collision energies were varied in the range of 9-44 eV (in the laboratory frame).
The major APCI-MS/MS fragmentations of protonated aflatoxins occurred at 30 eV collision energy. The main fragmentation channels were found to be the losses of a series of carbon monoxide molecules and loss of a methyl radical, leading to the formation of radical-type product ions. In addition, if the aflatoxin molecule contained an ether- or lactone-oxygen atom linked to a saturated carbon atom, loss of a water molecule was observed from the M + H ion, especially in the case of aflatoxins G1 and G2.
A relatively small modification in the structure of aflatoxins dramatically altered the fragmentation pathways and this was particularly true for aflatoxins B1 and B2. Due to the presence of a C = C double bond connected to the ether group in aflatoxin B1 no elimination of water was observed but, instead, formation of radical-type product ions occurred. Fragmentation of protonated aflatoxin B1 yielded the most abundant radical-type cations.
当存在于食物中时，黄曲霉毒素真菌毒素对健康特别危险。因此，从分析的角度来看，了解它们的质谱特性是必不可少的。本研究的目的是描述四种最常见的黄曲霉毒素：B1、B2、G1 和 G2 的碰撞诱导解离行为。
使用大气压化学电离（APCI）质谱（MS）与高效液相色谱（HPLC）结合，产生质子化的黄曲霉毒素。对于串联质谱（MS/MS）实验，氮气用作碰撞气体，并且在 9-44 eV 的范围内改变碰撞能量（在实验室框架中）。
质子化黄曲霉毒素的主要 APCI-MS/MS 碎裂发生在 30 eV 碰撞能量。发现主要的碎裂通道是一系列一氧化碳分子的损失和甲基自由基的损失，导致形成自由基型产物离子。此外，如果黄曲霉毒素分子含有与饱和碳原子相连的醚或内酯氧原子，则会从[M + H]+离子观察到水分子的损失，尤其是在黄曲霉毒素 G1 和 G2 的情况下。
黄曲霉毒素结构的微小改变极大地改变了碎裂途径，对于黄曲霉毒素 B1 和 B2 尤其如此。由于黄曲霉毒素 B1 中与醚基相连的 C = C 双键的存在，没有观察到水的消除，而是形成了自由基型产物离子。质子化黄曲霉毒素 B1 的碎裂产生了最丰富的自由基型阳离子。
