In this study, the QA/QC test for the combined application of DNPH cartridge – HPLC/UV method was investigated in the collection and analysis of formaldehyde in air using three types of DNPH cartridge samplers made by three independent manufacturers. For these experiments, gaseous standards of formaldehyde (FA) were prepared at 7 concentration levels that fell in the range of 44.1~3400 nmol/mol. According to our analysis, the levels of cartridge blank (0.13 ~ 0.26 ng) are found to be fairly high to require routine check up for each experiment. The recovery patterns of FA were highly comparable between different cartridge products, when standard gases are supplied in the concentration range up to 177 nmol/mol. All 3 types of DNPH cartridge exhibited highly similar recovery rates at concentrations below 1.7 ㎛ol/mol, while the maximum recovery was attained from the product B. The overall results of our study suggest that one should calibrate the samples in the optimal range of recovery with routine check up of blank values.

In this study, we attempted to evaluate the relationship between dilution‐to‐threshold (D/T) ratio derived by air dilution sensory (ADS) test and the concentration levels of both individual odorant (using H₂S and acetaldehyde (AA)) and their mixture. For the purpose of our comparative study, we prepared both standard gases of two individual compounds and their mixture at 9 concentration levels. Each of all these samples were analyzed by ADS test, and the results were analyzed in relation to their odor intensity. The results of individual odorant samples showed the two contrasting characteristics of each individual compound. H2S generally showed sensitive detection at low concentration but less sensitive detection with increasing concentration. In contrast, AA showed fairly contrasting trend with slow increasing sensitivity. When the D/T ratios estimated from individual samples were used to predict those of mixed samples, the results were reflecting the mixed effects of the basic characteristics owned by each individual compound. As the lower and upper odor intensities of mixed samples were best reflected by AA and H2S, respectively, the D/T ratio of mixed samples complied with the larger D/T values of each compound at a given odor intensity.

In this study, deodorizing efficiency of three deodorant products (1) A = ClO₂ Gel + charcoal, (2) B=Charcoal Gel, and (3) C = Gel (for Kimchi)) was investigated. For these experiments, a total of 15 odorants (4 reduced sulfur compounds, 2 volatile organic compounds, 7 carbonyl compounds, and 2 nitrogenous compounds) were investigated for a short term period. For the comparative analysis, 2 food types with strong odor properties (Kimchi and Fish) were selected and investigated. The analytical results were compared with respect to the blank sample (without deodorants) after normalization. Hence, if normalized concentration values are lower than unity one can assume that sample has positive deodorizing efficiency. The results of deodorant experiments indicate that the effects of the most common deodorant products are not effective enough to remove offensive odorants. However, the selection of deodorant products appears to be important, as they have very specific deodorizing efficiencies for certain compounds.

In this study, the emission characteristics of reduced sulfur compounds (RSC) were investigated under decaying conditions using 3 food types with strong odor properties: (1) Kimchi (KC), (2) Fresh fish (FF), and (3) Salted fish (SF). The concentrations of RSC from food decaying samples were measured 5 times during the full study period over 15 days. All the analysis of RSC were made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). According to our analysis, CH₃SH recorded the highest mean concentration (53.8 ppb) out of all RSCs investigated concurrently. Comparison between 3 food types showed that KC had the highest odor strength in primary stage, although it showed a notable decrease through time. On the other hand, FF and SF maintained generally low RSC concentrations in the beginning stage, but they showed large increases in emission concentrations with time. Thus, the results indicate that the relative pattern of RSC emissions tends to vary greatly with food types rather than RSC type.

In this study, the recovery rate of thermal desorbing (TD) method was investigated in relation to sample concentration and loading volume of reduced sulfur compounds (RSC). All the analysis of RSC was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The RSC measurement data were obtained by loading gaseous RSC standards prepared at 4 concentrations (10, 20, 50, 100 ppb) at 6 injection volumes (40, 80, 200, 400, 800, and 1200 mL). The recovery rates of each RSC were computed in terms of relationship between expected vs. measured values. According to our analysis, the following conclusions can be drawn. First, the results were less stable at short loading time (1 and 2 min at 40 mL/min) with reduced recovery rate, especially with light RSCs (H₂S and CH₃SH). On the other hand, at sufficiently high loading volume, their quantification was limited by off-scale peaks (at a near 50 ng) due to the breakthrough of cold trap in TD. Thus, the optimization of TD-based analysis may be considered as a prerequisite for analyzing the RSC in a reliable manner.

In this study, the removal characteristics of reduced sulfur compounds (RSC) were investigated against activated carbon (AC) by means of electric cooling and thermal desorption. To this end, three types of AC materials were selected and tested against gaseous RSC standards prepared at 50 ppb concentration. Each of these AC materials designated with its own target odorant compounds was tested for the removal rate of RSC by comparing their quantities between prior to and after passing the adsorption tube. All the analysis of RSC was made by Gas Chromatography (GC)/Pulsed Flame Photometric Detector (PFPD) combined with Air Server (AS)/Thermal Desorber (TD). The rate of RSC removal was quantified as a function of RSC loading time (Exp. 1) and of RSC flow rate into TD (Exp. 2). The results of Exp. 1 showed that the adsorption of RSC increased with RSC loading time (from as little as 1 to 20 min). In Exp. 2, the adsorption of RSC also increased in relation to RSC flow rate (10 to 100 mL/min). The removal rate of RSC was also distinguished by chemical properties such as the compounds of low molecular weights (H₂S and CH₃SH) vs. high ones (DMS and DMDS).

In this study, the concentrations of various hydrocarbon (HC) were measured from the ambient air at Mallipo beach after the Hebei Spirit oil spill accident on Dec. 2007. To determine HC levels in those samples, the analysis was made by SPME method aided by the GC/MS system. To produce quantitative HC data, all the calibrations were conducted in reference to toluene. The HC released from oil-covered soils were also analyzed by headspace method; according to this analysis, the concentrations of paraffinic (9), aromatic (8) and miscellaneous components (5 compounds) were found above a few tens of ppb. In ambient samples, 10 compounds were measured which consisted of 8 paraffinics and 2 aromatics. And they have the maximum and minimum concentration that were 34.3 ppb (n-undecane) and 2.84 ppb (toluene). However, the concentration levels of the 2 aromatic compounds (toluene and xylene) measured during this study period were not distinguished from those commonly observed from ambient air. Based on our analysis, we were able to confirm that the types and the concentration levels of hydrocarbons in ambient samples were in accord with those derivable from a large oil spill accident and the resulting weathering processes.