The Simultaneous Analysis of Aliphatic Chlorides in Air by Gas Chromatography ╱ Mass Spectrometry
碩士 === 逢甲大學 === 化學工程研究所 === 81 === The pretreatment in trace analyses for organic polluants in ambient air were necessary in Capillary column gas chromatogra- phic techniques. The concentration and desorption processes of the pretreatm...
Main Authors: | , |
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Other Authors: | |
Format: | Others |
Language: | zh-TW |
Published: |
1993
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Online Access: | http://ndltd.ncl.edu.tw/handle/83642863265832227122 |
Summary: | 碩士 === 逢甲大學 === 化學工程研究所 === 81 === The pretreatment in trace analyses for organic polluants in
ambient air were necessary in Capillary column gas
chromatogra- phic techniques. The concentration and
desorption processes of the pretreatment were complex, time
tedious,and might cause un- certain results. In this
investigation ,a fourteen aliphatic chlorides (from C1 to C3)
mixture sample has been analyzed by direct injection in
packed column gas chromatography. Since the fourteen aliphatic
chlorides were not completely separated by any single
liquid phase packed column in gas chro- matography. The
optimal separations of the mixed sample (Exclu- sion of 1,1
,1-trichloroethane and dichloromethane) was found from the
window diagram of two liquid phases with weight percen- tages
of 70% OV-17 and 30% FFAP. The relative separation time (
Separation factor,alpha) of the poorest couple was 1.11 in
the quantitative analysis of the mixed sample by using a two
meters column packed with the above percentages of the
liquid phases in mixed bed method. All fourteen aliphatic
chlorides were measured quantita- tively in four different
concentrations individually by using Gas Chromatohraphy ╱ Mass
Spectrometry (GC╱MS) . Although 1,1,1- trichloroethane and
dichloromethane were unable to be separated from the other
twelve compounds,the characteristic fragment of those
compounds,C2H3Cl2+ and C2H2Cl2+ ,were chosen to avoid the
peak overlap from other compounds in the selective ion mode
(SIM) method of the GC╱MS.The concentration of the fourteen
compounds were obtained under the SIM method in sub-ppm levels
with iodobu- tane as an internal standard. The results for
chloroethane was even sensitive to ppb levels. The linear
dynamic range of our mass spectrometer detector was over 3
orders of magnitude.
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