因水中植物、藻類過度繁殖所引起的優養化不僅會造成水質惡化及惡臭，大量繁殖的藻類甚至會產生毒素。其中最常被發現的有毒汙染物之一為微囊藻毒素 (Microcystin)，其對於肝臟和神經系統具有毒性，也會促進腫瘤生長，在多種異構體中Microcystin-LR (MC-LR) 最普遍且毒性最強。除了暴露於環境水體中之隱憂，人類也可能透過食物鏈而接觸到微囊藻毒素，故有必要開發一套快速方法檢測水環境中Microcystin濃度。 本研究使用固相萃取法 (Solid phase extraction,SPE) 結合硫醇官能基衍生化並利用MALDI-TOF MS檢測環境水樣中之微囊藻毒素：MC-LR與MC-YR。最佳化實驗步驟為50 mL 水樣使用Supelclean ENVI-18之固相吸附材料，以流速1 mL/min、5 mL 10%甲醇水溶液清洗及5 mL甲醇沖提，沖提液經吹氮濃縮並回溶後取出10 μL，並添加1 μL β-mercaptoethanol (BME) 衍生化試劑及40 μL Na2CO3緩衝溶液，於室溫下反應1 hr，並以50 μL 80%乙腈水溶液 (含0.1% TFA) 萃取出待測物。 本實驗MC-LR及MC-YR線性範圍為0.5-10 μg/L，決定係數分別為0.9939及0.9876，定量極限 (LOQ) 皆為0.3 μg/L，精密度 (precision) 以相對標準差 (RSD) 表示，皆小於9%，準確度 (accuracy) 以回收率表示，在93至116%間，顯示此方法穩定且具有良好的再現性。然在目前所收集的環境水樣檢測中，兩種微囊藻毒素待測物的含量皆低於本方法偵測極限。;Overbreeding of aquatic plants and algae not only causes deterioration of water quality, but some species of algae also produce toxins, one of the most commonly found being microcystin. Microcystin is toxic to the liver and nervous system, and also promotes tumor growth, with microcystin-LR (MC-LR) being the most prevalent and most toxic out of all the isoforms possible. In addition to the hidden dangers of exposure to environmental microcystin in water, humans may also come into contact with microcystin through our foods, as the toxin accumulates via the food chain. In this study, a solid phase extraction (SPE) method coupled with thiol derivation and matrix-assisted laser desorption/ ionization time of flight mass spectrometry (MALDI-TOF MS) was developed, and was able to successfully detect microcystins in water. The best experimental conditions included water sample at a flow rate of 1 mL / min, washing with 10% methanol (in water), and elution with 5 mL methanol for SPE (Supelclean ENVI-18). The eluent was dried under nitrogen and reconstituted with β-mercaptoethanol to derivatize the analyte. In this study, the linear ranges of MC-LR and MC-YR were 0.5-10 μg/L, with coefficients of determination (r2) of 0.9939 and 0.9876, respectively. Limit of detection (LOD) was 0.2 μg/L. The method had good accuracy (recovery 93-116%) and precision (RSD < 9%). The concentrations of microcystin-LR and microcystin-YR in water samples were lower than the limits of detection.
