| 摘要: | 一個快速且有機溶劑用量少的方法檢測3種防曬乳成份ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (HMS), 2-hydroxy-4-methoxybenzophenone (BP-3) 及兩種與BP-3有類似結構的羥基化二苯甲酮類2,4-Dihydroxybenzophenone (BP-1) 和 2,2’-Dihydroxy-4-methoxybenzophenone (BP-8) 在水樣中的濃度。此方法利用超音波輔助分散式液液微萃取法 (Ultrasound-assisted dispersive liquid-liquid microextraction, UA-DLLME) 搭配同步 (In situ) 衍生化在一步中同時萃取及衍生化並利用氣相層析質譜儀來檢測。 利用兩個實驗設計方法：直交設計法 (Orthogonal array design, OAD) 與中央合成設計 (Central composite design, CCD) 來對萃取及衍生化的各項參數做一個探討，實驗所得最佳化條件為將萃取劑四氯乙烯 (tetrachloroethylene) 15 μL、與衍生化試劑 N,O-Bis(trimethylsilyl)trifluroacetamide (BSTFA) 20 μL溶於分散劑丙酮 (acetone) 750 μL後快速打入10 mL含有0.5克氯化鈉的水樣當中，經過1分鐘的超音波震盪後以5000 rpm速率離心10分鐘後，利用60瓦225秒的微波功率及秒數來使衍生化更為完全。 在本研究的定量極限 (limits of quantitations, LOQs) 皆小於2 ng/L，而對其做精密度及準確度的測試，其相對標準偏差 (relative standard deviations, RSDs) 皆小於15 %，待測物的回收率介於62和92 %之間，利用標準添加法測得環境水樣中5種防曬乳成份的濃度在12.3到42.3 ng/L，而其中BP-3在環境水樣的所含濃度最高介於12.3到21.4 ng/L。 整體上來說，超音波輔助分散式液液微萃取法搭配同步衍生化是一個良好，且有效率的萃取水樣中防曬乳成份並可利用在環境的檢測上面，同時它是一個簡單、方便、快速、成本低且環保的一個實驗方法A rapid and solvent-minimized procedure for the determination of three UV filters: ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (HMS), 2-hydroxy-4-methoxybenzophenone (BP-3) and two related hydroxylated benzophenones (2,4-dihydroxy-benzophenone (BP-1) and 2,2’-dihydroxy-4-methoxybenzophenone (BP-8)) in water samples is presented. The method involves one-step in-sample silylation coupled with ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) prior to their determination using gas chromatography-mass spectrometry (GC-MS). The dual experimental design protocols (i.e., orthogonal array design (OAD) and central composite design (CCD)) to evaluate the effects of various derivatization and extraction parameters were investigated and the conditions optimized. The optimal derivatization and extraction conditions involved the rapid injection of a mixture of 750 μL of acetone (as a dispersant), 15 μL of tetrachloroethylene (as an extractant), and 20 μL of BSTFA (derivatizing agent) into a 10 mL of water sample containing 0.5 g of sodium chloride in a conical bottom glass tube. After ultrasonication for 1.0 min and centrifugation at 5000 rpm (10 min), the sedimented phase was then microwave irradiated at 60 W for 225 seconds to accelerate TMS-derivatization. The limits of quantitations (LOQs) were less than 2 ng/L. The precision for these analytes, as indicated by relative standard deviations (RSDs), were less than 15% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 62 and 92%. Using a standard addition method, the preliminary results show that total concentrations of these five UV filters ranged from 12.3 to 42.3 ng/L, and BP-3 contributed the most to the total UV filters levels in water samples which ranged from 12.3 to 21.4 ng/L in this study. Overall, one-step in-sample silylation coupled with UA-DLLME appears to be a good alternative extraction method for the determination of UV filters in environmental water samples, in that it is a simple, low cost, effective, and eco-friendly analytical method. |
