Saxitoxins (STXs) are potent neurotoxins produced by marine dinoflagellates or freshwater cyanobacteria, known to cause acute and eventually fatal human intoxications, which are classified as Paralytic Shellfish Poisonings (PSPs). Rapid analysis of STXs in blood plasma can be used for a timely diagnosis and confirmation of PSPs. We developed a fast and simple method of STX extraction based on plasma sample acidification and precipitation by acetonitrile, followed by quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Our approach provides the results ≤30 min, with a limit of detection (LOD) of 2.8 ng/mL and a lower limit of quantification (LLOQ) of 5.0 ng/mL. Within-run and between-run precision experiments showed good reproducibility with ≤15 % values. Standard curves for calibration were linear with correlation coefficients ≥0.98 across the assay calibration range (5-200 ng/mL). In an interlaboratory analytical exercise, the method was found to be 100% accurate in determining the presence or absence of STX in human plasma specimens, with recovery values of 86-99 %. This simple method for STX determination in animal or human plasma can quickly and reliably diagnose STX exposures and confirm suspected PSPs cases to facilitate patient treatment or expedite necessary public health or security actions.

中文翻译：

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一种快速可靠的 LC-MS/MS 方法，用于定量血浆样品中的石房蛤毒素

石房蛤毒素 (STX) 是由海洋甲藻或淡水蓝藻产生的强效神经毒素，已知会导致急性并最终致命的人类中毒，被归类为麻痹性贝类中毒 (PSP)。血浆中STX的快速分析可用于PSP的及时诊断和确认。我们开发了一种快速、简单的 STX 提取方法，该方法基于血浆样品酸化和乙腈沉淀，然后使用液相色谱-串联质谱 (LC-MS/MS) 进行定量。我们的方法可在 ≤30 分钟内提供结果，检测限 (LOD) 为 2.8 ng/mL，定量下限 (LLOQ) 为 5.0 ng/mL。批内和批间精密度实验显示出良好的重现性，值≤15%。校准的标准曲线在整个检测校准范围 (5-200 ng/mL) 内呈线性，相关系数≥0.98。在实验室间分析活动中，发现该方法在确定人血浆样本中是否存在 STX 方面准确度为 100%，回收率为 86-99%。这种测定动物或人体血浆中 STX 的简单方法可以快速可靠地诊断 STX 暴露并确认可疑的 PSP 病例，以促进患者治疗或加快必要的公共卫生或安全行动。