本研究以三液相動態微萃取法(dynamic three-phase microextraction, LLLME)結合多元素石墨爐原子吸收光譜偵測海水中的鉛、銅、鋅元素，利用有機相中的螯合劑(dithizone)，螯合海水裡的重金屬，再反萃重金屬至受層(acceptor phase)硝酸中進行偵測，此方法不但簡便，分析時間也大大縮短。探討各種可能影響萃取效率的變因包括：有機溶劑的選擇、予層(donor phase)海水樣品和受層(acceptor phase)硝酸pH值、螯合劑用量、萃取時間與攪拌速率，在最佳化的條件下，鉛、銅、鋅的偵測極限分別為9.0*10-3μg/l，1.9*10-1μg/l，4.8*10-2μg/l；精密度為海水標準品NASS-5重複七次分析的相對標準偏差(RSDs%)表示之，本實驗鉛、銅、鋅的精密度為19.5%，18.9%，10.1%。
本分析方法利用標準添加法來測定兩種不同標準海水CASS-4、NASS-5鉛、銅、鋅的含量，然而，其線性與定量結果並不理想，唯有定量標準海水CASS-4銅的線性(R2=0.9984)良好且定量結果可落在認證值的85~115%。

A new method of dynamic three-phase microextraction (LLLME) combined with multi-element graphite furnance atomic absorption spectrometer (GFAAS) was proposed for the determination of trace Pb, Cu, and Zn in sea water. In a extraction step, three elements in 40 ml of sea water adjusted to basic condition (donor phase) were extracted into a organic film containing a chelating agent (dithizone) in o-xylene and then back-extracted into 10 μl of nitric acid solution (acceptor phase) for determination by GFAAS. Because the organic and acceptor phase were repeatedly moved in and out of the hollow fiber channel, the organic film is renewable, and the relative movement between the acceptor phase and the organic phase would enhance the enrichment factor. Under the optimized conditions, the detection limits were 9.0*10-3μg/l，1.9*10-1μg/l，4.8*10-2μg/l for lead, copper and zinc. The relative standard deviations (RSDs) were in the range of 10.1~19.5%. Two standard reference materials (CASS-4, NASS-5) were used to confirm the accuracy of the technique, however, the found values for most elements were not within 85~115% of certified values.

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