| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 84 === The volatile organic compounds (VOCs) are important
toxic pollutants in the ambient air which can affect human
health. If one is exposed in the environment with high level of
VOCs will cause physiological changes including DNA damages that
may lead to cancer. Exposure to VOCs will also bring stimulation
of mucous membrane of the breathway and eyes. Besides, VOCs can
anesthetize the centeral nerve system.
In order to estimate the effects of VOCs on our environment and
toxic damagesto human physiology, analytical techniques for VOCs
have been recently emphasized on developing procedures detect
much more compounds and at lower concentrations. The instruments
used in this work. Including thermal desorption system, GC-FID
and GC-MS. In the process of analysis, internal standards with
or without istopes are used to enhance the accuracy of
determination. Low-volume-flow pumps are used
to drive the air sample through the column packed with Tenax TA
as adsorbent to collect VOCs. At first, VOCs in the sampling
column are analytes desorbed at temperature of 180℃. Then are
condensed in the cryo-trap by liquid nitrogen. Helium acts as
carrier gas to drive the desorbed VOCs to GC. Finally, the
analytes separated by a capillary column goes on for quilitative
and quantitative analysis in MS. In this study, the overall
recoveries range from 78.3％ to 109.8％. The rae of detection
limits is 0.69 ngqsymbol 126 \f "Symbol" \s 12 ~ 6.32 ng. The
relative standard deviations of relention times the range of
0.26％ symbol 126 \f "Symbol" \s 12 ~ 1.26％. The feasibility of
this method is tested by real sample analyses from different
sources.
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