• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.

• Analytical Science and Technology
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• v.13 no.5
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• pp.683-692
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• 2000

The volatile organic compounds emitted from food wrapping films when it was used at high temperatures. However, the testing method based on solvent extraction may not be suitable for determination of volatile organic compounds from food wrapping films. Therefore, thermal extraction device was investigated in the study for reflection of actual usage conditions at home and restaurant. In this study, PVC food wrapping films were exposed to normal use condition controlled from $50^{\circ}C$ to $120^{\circ}C$ and collected on sorbent trap. Then, emitted VOCs from the films were analyzed with On-column cryofocusing-GC/MS system. The major VOCs emitted from films were $C_{12}-C_{18}$ paraffinic hydrocarbons, dimethylphthalate, alkylphenols, known as endocrine disrupting chemical, such as tetramethylbutylphenol, tert-butylphenol, and nonylphenol. The concentration of tetramethylbutylphenol emitted from PVC films was $0.07ng/cm^2$ at $50^{\circ}C$, rapidly increased with temperature, $3.94ng/cm^2$ at $100^{\circ}C$.