Ifremer, Laboratoire Phycotoxines, Rue de l'Ile d'Yeu, 44311, Nantes, France.
LUNAM, Université de Nantes, MMS EA2160, Faculté de Pharmacie, 9 rue Bias, 44035 Nantes, France.
J Chromatogr A. 2018 Oct 12;1571:16-28. doi: 10.1016/j.chroma.2018.08.008. Epub 2018 Aug 4.
Ciguatera Fish Poisoning (CFP) is primarily caused by consumption of tropical and sub-tropical fish contaminated by Ciguatoxins (CTXs). These lipid-soluble, polyether neurotoxins are produced by dinoflagellates in the genera Gambierdiscus and Fukuyoa. While there is no regulatory level in Europe for CTXs, the European Food Safety Authority (EFSA) adopted the United States guidance level of 0.01 μg P-CTX1B eq.kg of fish. This limit is extremely low and requires significant improvement in the detection of CTXs. In this study, we compared analytical protocols based on liquid chromatography coupled to tandem low or high resolution mass spectrometry (LC-LRMS or HRMS) to find the best conditions for sensitivity and/or selectivity. Different approaches such as LC conditions, ion choice and acquisition modes, were evaluated to detect the Pacific-ciguatoxins (P-CTXs) on a triple quadrupole (API4000 Qtrap, Sciex) or a quadrupole time of flight (QTOF 6550, Agilent Technologies) spectrometer. Moreover, matrix effects were calculated using matrix-matched calibration solutions of P-CTX1B and P-CTX3C prepared in purified fish extract. Subsequently, the method performance was assessed on naturally contaminated samples of seafood and phytoplankton. With LRMS, the ammoniated adduct ion used as a precursor ion showed an advantage for selectivity through confirmatory transitions, without affecting signal-to-noise ratios, and hence limits of detection (LODs). As also reported by some studies in the literature, methanol-based mobile phase gave better selectivity and sensitivity for the detection of P-CTXs. While the LOD for P-CTX1B and P-CTX3C met the EFSA recommendation level when using LRMS, the findings suggested careful evaluation of instrumental parameters for determination of CTXs. LODs were significantly higher for HRMS, which currently results in the need for a significantly higher sample intake. Nevertheless, HRMS allowed for the identification of artefacts and may allow for improved confirmation of the identity of P-CTXs analogues. Consequently, LRMS and HRMS are considered complementary to ensure adequate quantitation and identification of P-CTXs.
雪卡毒素中毒（CFP）主要是由食用受雪卡毒素（CTXs）污染的热带和亚热带鱼类引起的。这些脂溶性聚醚神经毒素由双鞭甲藻属和 F ukuyoa 属中的甲藻产生。虽然欧洲没有 CTXs 的监管水平，但欧洲食品安全局（EFSA）采用了美国的指导水平，即鱼中 0.01μg P-CTX1B eq/kg。这个限值非常低，需要显著提高 CTXs 的检测水平。在这项研究中，我们比较了基于液相色谱串联低分辨或高分辨质谱（LC-LRMS 或 HRMS）的分析方案，以找到提高灵敏度和/或选择性的最佳条件。评估了不同的方法，如 LC 条件、离子选择和采集模式，以在三重四极杆（API4000 Qtrap，Sciex）或四极杆飞行时间（QTOF 6550，Agilent Technologies）谱仪上检测太平洋雪卡毒素（P-CTXs）。此外，还使用在纯化的鱼提取物中制备的 P-CTX1B 和 P-CTX3C 的基质匹配校准溶液计算了基质效应。随后，该方法在天然污染的海鲜和浮游植物样品上进行了性能评估。使用 LRMS，作为前体离子的氨化加合物通过确证转换显示出选择性优势，而不会影响信噪比，从而影响检测限（LOD）。正如文献中的一些研究报道的那样，基于甲醇的流动相可提高 P-CTXs 检测的选择性和灵敏度。当使用 LRMS 时，P-CTX1B 和 P-CTX3C 的 LOD 符合 EFSA 的推荐水平，但研究结果表明，需要仔细评估仪器参数以确定 CTXs。对于 HRMS，LOD 显著更高，这导致需要显著增加样品摄入量。然而，HRMS 允许识别伪影，并可能允许改进 P-CTXs 类似物的身份确认。因此，LRMS 和 HRMS 被认为是互补的，以确保充分定量和鉴定 P-CTXs。
