以 HPLC-ICP-MS 分析微量有機錫農藥之方法建立

Abstract

近年來國內農藥抽檢多次查獲殺菌劑三苯醋錫，顯示環境中可能殘留禁用的有機錫農藥。由於錫具有一般金屬不易分解及在環境中會累積的特性，其毒性可經食物鏈生物濃縮與累積效應進而危害各種生物及生態系統。然而目前對於環境中殘留有機錫農藥的檢驗方法尚未建立，因此本研究欲探討以高效能液相層析串聯感應耦合電漿質譜法進行土壤中有機錫農藥分析的可行性。除了禁用的三苯醋錫外，本研究亦針對目前國內可合法使用的有機錫殺螨劑芬佈賜進行試驗。研究中使用逆相層析管柱 Agilent Poroshell 120 EC-C18 及 Merck LichrospherR 100 RP-8 分別進行兩種有機錫農藥的分離。結果顯示，殺菌劑三苯醋錫的最適分析條件為以甲醇與 1% 氯化鈉緩衝溶液作為移動相，搭配 Agilent Poroshell 120 EC-C18，流速為 0.5 mL/min。殺螨劑芬佈賜的最適分析條件則為以氰甲烷與 0.6% 氯化鈉緩衝溶液作為移動相，搭配 Merck LichrospherR 100 RP-8，流速為 0.5 mL/min。此外，三苯醋錫及芬佈賜在檢量線範圍 0-500 μg/L 的相關係數平方值分別為 0.9994 及 0.9988，且低濃度範圍的相關係數平方值皆大於 0.997，顯示此兩種農藥與其分析方法的反應訊號呈現良好線性關係，線性範圍廣。三苯醋錫及芬佈賜標準品的儀器偵測極限分別為 1 及 7.5 μg/L。而土壤中有機錫農藥的萃取結果顯示，索氏萃取法較超音波震盪法及往返式震盪法的萃取效果佳，可有效自土壤中萃取有機錫農藥。其中，三苯醋錫的最適合萃取條件為以甲醇搭配索氏萃取法萃取 6 小時，其回收率為 104.84 ± 12.32%；芬佈賜的最適萃取條件則為以正己烷與丙酮比例 90/10 (v/v) 萃取 8 小時，經溶劑置換後，其回收率為 97.79 ± 9.60%。三苯醋錫及芬佈賜的方法偵測極限分別為 1.017 及 8.932 μg/L，且此方法藉由土壤真實樣品的分析可有效獲得驗證。因此利用 HPLC 串聯 ICP-MS 進行土壤中微量有機錫農藥的分析具有可行性。

A banned organotin pesticide, fentin acetate, was found on random inspection of pesticides in Taiwan recently. It implies that the prohibited organotin pesticides could spread over in environment. Due to the common properties of metals, such as resistance and accumulation in environment, tin could damage the bio- and eco-system through bioconcentration and bioaccumulation. In this research, a method based on high-performance liquid chromatography-inductively coupled plasma mass spectrometric (HPLC-ICP-MS) analysis was established for the analysis of organotin compounds, including fentin acetate and a acaricide fenbutatin oxide which can be legally used in Taiwan. Several conditions of HPLC were optimized for organotin pesticides. The results showed that the optimum conditions to analyze fentin acetate for type of separating column, composition of mobile phase, and flow rate, were Agilent Poroshell 120 EC-C18, 90/10 methanol/sodium chloride buffer solution, and 0.5 mL/min, respectively. While the optimum conditions to analyze fenbutatin oxide were for type of separating column, composition of mobile phase, and flow rate, were Merck LichrospherR 100 RP-8, 80/20 acetonitrile/sodium chloride buffer solution, and 0.5 mL/min, respectively. Successful analysis of organotin pesticides by HPLC-ICP-MS was performed. The coefficient of determination (r2) of two pesticides were up to 0.998, indicating good linearity of calibration curves. Instrument detection limit for fentin acetate and fenbutatin oxide were 1 and 7.5 μg/L, respectively. Compared to ultrasonic extraction and shaking extraction, soxhlet extraction was the best way to extract organotin pesticides from soil. The recovery for fentin acetate was 104.84%, while fenbutatin oxide was 97.79%. Method detection limit for fentin acetate and fenbutatin oxide were 1.017 and 8.932 μg/L, respectively.