本實驗開發一種新型態的溶劑微萃取法-一滴溶劑萃取一滴樣品溶液之超微量萃取法（DDSME）結合氣相層析離子阱質譜儀對甲氧基苯乙酮異構物進行定量分析，本方法具備了快速、裝置與操作簡便以及極少的溶劑與樣品使用量等優點。萃取最佳化後所得到的結果為利用甲苯作為萃取溶劑並控制其液滴大小在0.5μL、萃取時間為5分鐘及水樣不添加任何鹽類條件下可得到最佳分析物訊號強度。於此最佳條件下所得到的偵測極限為1ng/mL，相對標準偏差值小於2.6（n＝5），線性範圍從0.01到5μg/mL(r2>0.954)。實驗最後亦將DDSME方法與其他樣品前處理技術，如：液-液萃取法（LLE）、一滴溶劑微萃取法（SDME）、中空纖維-液相微萃取法（HF-LPME）及固相微萃取法（SPME）進行偵測極限的比較。比較後發現本方法能較LLE（25ng/mL）得到一更低的偵測極限濃度，而且此結果與利用SDME（0.5ng/mL）、HF-LPME（1ng/mL）及SPME（0.5ng/mL）等方法所得到的偵測極限結果不相上下。 A novel analytical technique termed drop-to-drop solvent microextraction (DDSME) was developed to determine three methoxyacetophenone isomers in one drop of water, which were then detected by gas chromatography/mass spectrometry using electronic ionization mass spectrometry for quantification analysis. The advantages of this method are rapidity, convenience, ease of operation, simplicity of the device, and extremely little solvent and sample consumption. The best optimum parameters for the DDSME technique were as follows: extraction time, 5 min; usingtoluene as the extraction solvent; volume of extraction solvent, 0.5μL and no salt addition. The limit of detection (LOD) for this technique was 1 ng/mL. The relative standard deviation was less than 2.6% (n=5). The linear range of the calibration curve of DDSME is from 0.01 to 5μg/mL with correlation coefficient (r2) of >0.954. In the comparison of the LOD of DDSME with other sample pretreatment methods including liquid-liquid extraction (LLE), single drop microextraction (SDME), hollow fiber based liquid phase microextraction(HF-LPME), and solid phasemicroextraction(SPME), this method shows much better than the LLE (25 ng/mL) and it is compatible with SDME (0.5ng/mL), HF-LPME (1ng/mL), and SPME (0.5 ng/mL).
