In this study, the most effective salting-out effect has been examined in terms of application of various inorganic salts (NaCl, Na₂S0₄, NaHSO₃) using Alkali impregnated filter-Headspace-GC/FID. Five various VFAs (propionic acid (99.5%), r-butyric acid (99%), butyric acid (99%), i-valerie acid (99%), valerie acid (99%)) have been used. VFAs have been analyzed by adding 30%, 70%, 100%, 150%, 200% of different inorganic salts with HS-GC/FID. The efficiency of salting-out effect was obtained from the values of peak area in chromatogram. The most effective salting-out effect for applired inorganic salts was observed at 100% saturation. It was confirmed NaHSO₃ for salting-out effect was the best among inorganic salts. In addition, NaHSO₃ showed more efficiency of salting-out effect than NaCl as molecular weight of VFAs increases.

Volatile fatty acids (VFAs) are malodor compounds which are produced from the decomposition of animal or plant species. It is very difficult to detect VFAs due to their strong adsorptive properties. In this study we develop an analytical method using headspace-GC/FID with an alkali-impregnated filter sampling. The addition of NaCl and H₂S0₄ makes the salt-out and pH-lowering effect, respectively. The high boiling points (141~185℃) and vapor pressures require a high temperature and long heating time for the standard sample in vials to reach an equilibrium. The analytical response was highest when the absolute quantity in the sample was 5 mL in a 22 mL vial. The addition of NaCl for the salt-out effect can give a higher sensitiviry by a factor of 1.1~4.2 than that of Na₂SO₄. The mass amount of 4.6 g of NaCl can result in a higher sensitivity, which is higher than the supersaturated solubility of 4.2 g. The concentration of H₂SO₄ is as low as 2% (v/v). When the concentration range is 8.3 -562.1 ppb, a coefficient of R²~0.99 can be obtained for the five VFAs samples. The analytical errors in a reproducibility test are less than 10% and the detection limit is estimated to be 0.05~0.1 ppb. Our headspace-GC/FID analytical method can be utilized to effectively detect the five kinds of VFAs which shall be restricted in Republic of Korea from the year of 2010.

An analytical method for trimethylamine in ambient air was developed, using headspace gas chromatography with flame ionization detection. Trimethylamine was collected on the acid filter which was impregnated sulfuric aicd in the 47 ㎜ diameter of glass fiber filter. Trimethylamine collected on the acid filter was regenerated in the headspace vial and introduced into the GC analytical column directly. Several parameters such as sample volume, equilibrium temperature and time, and slurry method of filter were optimized to provide maximum detection response. Resolution power also compared according to liquid phase of analytical column. The detection limit of method was 0.13 ppb with 50 L sampling volume. The developed acid filter method is easy to deal with the field sampling and the method was adopted as the standard method for odor analysis in Korea.

In this study, the TVOCs and odor active compounds emitted from 3 PVC and 5 natural wallpapers were analyzed. The emitted odor intensities and characteristics of the wallpapers were estimated using air dilution sensory and direct olfactory methods. The emissions of TVOCs were measured using the SPME-cryogenic emission test method, which was modified from the RAL-GZ 479 method, which is used in Germany to evaluate the quality of wallpapers. It was found that there was no significant correlation between the emissions of TVOCs and the odor concentration. However, a correlation (0.57) was found between the emitted VOCs and the odor concentration of the low molecular weight compounds, which have strong volatilities, ranging from n-C6 to n-C10. For all 8 wallpapers, vinegar like odor was commonly perceived, with acetic acid identified as the main odor active compound withinthe odor. Benzaldehyde and esters, such as ethyl acrylate and n-butyl acrylate, were identified as odor active compounds, which were expressed as having rubber like smells by the panelists. These results indicate that odor should be included as a domestic regulation for the pollutants emitted from building materials. The identification of odor active compounds emitted from building materials could be useful in the production of eco-environment products.

In this study, alkali impregnated filter sampling method was considered for VFAs in ambient air. When KOH concentration was 0.5 N and sampling flow velocity was 5~10 L/min the sampling efficiency was higher than 90 percent. More than 3 minute shaking make the sampled filter to be suspended in the 22.3 mL Vial. Alkali impregnated filter sampling method showed more than 4 times higher response compared to alkali solution sampling method, when the sample was analysed by headspace-gas chromatography. Five kinds of volatile fatty acids (propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, valeric acid) were detected within 1.0~9.8 ppbv in the cow shed by alkali impregnated filter method and headspace gas chromatography. The alkali impregnated filter method was the most suitable sampling method for ambient volatile fatty acids with headspace gas chromatography analysis.