Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 126/3, 625 00, Brno, Czech Republic.
Anal Bioanal Chem. 2010 Oct;398(3):1231-7. doi: 10.1007/s00216-010-3860-z. Epub 2010 Jun 10.
Microcystins are cyclic peptide toxins with hepatotoxic and tumour-promoting properties which are produced in high quantities in freshwater cyanobacterial water blooms, and several studies have reported microcystin accumulation in fish with possible food transfer to humans. In this study, we provide the first comparison of liquid chromatography with single mass-spectrometric and with tandem mass-spectrometric detection for analyses of microcystins in complex fish tissue samples. Use of traditional single mass spectrometry (i.e. monitoring of ions with m/z 519.5 for microcystin-RR and m/z 995.5 for microcystin-LR) was found to provide false-positive responses, thus overestimating the concentrations of microcystins in the tissue samples. More selective tandem mass spectrometry seems to provide more reliable results. The concentrations of microcystins detected by tandem mass spectrometry in fish from controlled-exposure experiments were more than 50% lower in comparison with concentrations obtained by single mass spectrometry. Extensive analyses of edible fish parts-muscles (148 fish specimens from eight different species from five natural reservoirs with dense cyanobacterial water blooms)-showed negligible microcystin concentrations (all analyses below the limit of detection; limit of detection of 1.2-5.4 ng/g fresh weight for microcystin-RR, microcystin-YR and microcystin-LR in multiple reaction monitoring mode). Our findings have practical consequences for critical re-evaluation of the health risks of microcystins accumulated in fish.
微囊藻毒素是具有肝毒性和肿瘤促进特性的环状肽毒素，在淡水蓝藻水华大量产生，并且有几项研究报告了鱼类中微囊藻毒素的积累，可能会通过食物转移给人类。在这项研究中，我们首次比较了液相色谱法与单质谱和串联质谱检测法，用于分析复杂的鱼类组织样本中的微囊藻毒素。使用传统的单质谱法（即监测 m/z 519.5 处的离子用于微囊藻毒素-RR 和 m/z 995.5 处的微囊藻毒素-LR）被发现会产生假阳性反应，从而高估了组织样本中微囊藻毒素的浓度。更具选择性的串联质谱似乎提供了更可靠的结果。与单质谱法相比，在受控暴露实验中，用串联质谱法检测到的鱼类中的微囊藻毒素浓度降低了 50%以上。对来自五个天然水藻密集的水库的 8 个不同物种的 148 个可食用鱼部分（肌肉）进行了广泛的分析，结果表明微囊藻毒素的浓度可忽略不计（所有分析均低于检测限；微囊藻毒素-RR、微囊藻毒素-YR 和微囊藻毒素-LR 在多重反应监测模式下的检测限为 1.2-5.4ng/g 鲜重）。我们的发现对重新评估鱼类中积累的微囊藻毒素的健康风险具有实际意义。
