超臨界二氧化碳是最普遍被使用當作超臨界流體，來萃取土壤、空氣微粒、柴油煤煙、及沈積物等固態環境污染物中的待測物。近年來超臨界流體萃取已經變成一倍受矚目的樣品前處理技術。而質譜儀由於其具有高靈敏度，且其在結構辨認上又是經常使用的儀器，當和氣相層析儀串連後，具相當選擇性和高靈敏度，使得其在分析環境中複雜的有機汙染物的能力大大的超越其它傳統性的偵測儀器，近年來已逐漸成為環境分析上一個不可或缺的工具。本實驗針對美國環保署（USEPA）與先進國家十分重視的十六種多苯環芳香烴（PAH)，進行其在不同土壤中的定性、定量分析，本研究中主要使用超臨界流體萃取當作樣品的前處理技術，萃取出所要的分析物，此一技術的效率明顯的和傳統的索氏及超音波萃取法不同。因為超臨界流體萃取只需要很短的萃取時間，而且溶劑的使用量少。實驗中以PAH的標準溶液利用混漿法添加至土壤中，配製成標準土壤，以此已知濃度之標準土壤來建立萃取的條件，並進而研究不同種類的土壤，其基質對回收率的影響，實驗中針對泥沙、泥土、黏土等三種土壤進行比較，所建立之
方法對泥沙中的PAH有最佳的萃取效率，泥土次之，黏土中的PAH明顯地就較不易萃出。另外本實驗同時也使用一新的檢測技術－同位素稀釋氣相層析質譜法，來進行在不同土壤樣品中的十六種PAH的定性、定量分析。實驗中利用五種同位素之內標品，配合同位素稀釋質譜法來偵測受到高污染的土壤中受管制的十六種多苯環芳香烴，五種同位素之內標品為(1)naphthalene ( d-8 , m/z 136 ) , (2) phenanthrene ( d-10 , m/z188 ) , (3) pyrene ( d-10 , m/z 212 ) , (4) chrysene ( d-12 , m/z 240) , and (5) benzo(g,h,i)perylene ( d-12 , m/z 288 ) 。當土壤作完前處理後，以超臨界二氧化碳萃取不經淨化的部驟，直接由IDMS法去定量，並經由CRM樣品之多次驗證，測出的結果皆在證書的範圍內，證明此法具高度之準確性與精密性。

Supercritical fluid extraction has become a prominent sample
preparation technique in recent years . Supercritical CO2 has
been the most common fluid for the extraction of organic
pollutants from environment sample (e.g. , soil , air
particulate matter , diesel soot and sediment etc. …) .Mass
spectrometry with high sensitivity is one of the most widely
applicable instrument to elucidate the structure of the chemical
compounds .Gas chromatography ( GC ) coupled with the mass
spectrometry ( GC-MS ) is the technique that has provided the
conclusive detailed data for both qualitative and quantative
analysis of many types of environmental samples. It possesses
high selectivity and high sensitivity that supply capability of
analyzing complex organic pollutants in the environment .In
recent years , GC-MS has become an indispensable technique in
environmental chemistry . This research aims at the development
of a new sample pretreatment technique for 16 important
polynuclear aromatic hydrocarbons , PAH , in soil samples .
Theses compounds are regulated by many developed countries in
their environmental pollution control regulation . This method
has gained increased attention as a potential replacement for
conventional solvent extraction technique (e. g. , sonication or
soxhlet extraction ) because of SFE's ability to quantitatively
extract organic pollutants from environmental soils in relative
short time while nearly eliminating the need for organic
solvent.Soil samples were prepared by immersing selected type of
soil PAH/dichoromethane solutions followed by mechanical mixing
. The standard soil samples thus obtained were used to establish
SFE experimental parameters . Three different types of soil
samples were prepared and utilized in this study . The results
show that the trend of PAH recovery for the three types of soil
is sand＞soil＞clay .Another research aim at the development of
a new examined technique using isotope dilution GC-mass
spectrometry(ID GC-MS)for analyzing tested for 16 important
polynuclear aromatic hydrocarbons , PAHs , in different soil
samples . Five appropriate deuterated internal standards were
used in conjuction with ID GC-MS to determine the 16 important
PAHs in polluted soil . The five appropriate deuterated internal
standards include (1) naphthalene ( d-8 , m/z 136 ) , (2)
phenanthrene ( d-10 , m/z 188 ) , (3) pyrene ( d-10 , m/z 212 )
, (4) chrysene ( d-12 , m/z 240) , and (5) benzo(g,h,i)perylene
( d-12 , m/z 288 ) . After the pretreatment of soil sample with
supercritical fluid extration ( SFE ) , samples were subjected
to ID GC-MS for analysis . With this technique , determination
the contants of PAHs in soil are better in precision and
accuracy . The feasibility of this method is confirmed by
numerous analyses of both CRM and real-world samples .
Supercritical fluid extraction has become a prominent sample