| Summary: | 碩士 === 國立成功大學 === 環境工程研究所 === 82 === In general, high pressures, high temperatures, and long time
enhance the solubility of PAHs and thus improve the of
extraction. The results show that for low-molecular weight
(2-ring naphthalene through 4-ring chrysene) pressure is the
most dominant factor for extraction. For high-molecular weight
PAHs, however, both pressure and temperature affect the
recovery rate. The addition of a proper modifier helped the
extraction. It was foumd that prior to the continuous pumping
of modifier methylene chloride (CH2Cl2) into the extraction
vessel during extraction, addition of 30 uL of CH2Cl2 to the
XAD-2 resin improved the yield. The optimal extraction result
was obtained when a 1-mL ertraction vessel was used, and the
extraction was carried out at 380 atm 140C, with an addition of
CH2Cl2 at 30 uL + 5.0 uL/min, 1 min. of static extraction,
followed by 40 min. of dynamic extraction. these conditions,
the recovery rate of all fourteen PAHs were above 96%.
Compared to traditional Soxhlet extraction SFE/GC gave much
recoveries of the fourteen PAHs. Also, while SFE yield 96%
rate with only 40 minutes and 110 uL of methylene chloride,
result from Soxhlet extraction required 33 hours and 800 mL of
solvent, not to mention the problem of its subsequent waste
disposal. In terms of both cleanness, time consumption, health
and environmental impact, SFE is superior to traditional
Soxhlet extraction. SFE will become a major useful and
powerful tool in organic environmental chemical analyses. In
the future, a simplified portable personal pump will be the
hope to substitute the traditional PS-1 sampler for for shorter
(1-2 hours) sampling periods, thus hourly variationtrations in
the ambient air may be monitored. 3. concentrations in the
ambient air may be monitored.
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