Comparison of Water Pretreatment Devices for the Measurement of Polar Odorous Compounds

A major problem of measuring polar compounds in the air is water vapor. Therefore, it is important to use a water pretreatment device prior to sampling and analysis. However, many studies have reported the occurrence of many problems following the application of an existing water pretreatment device. Accordingly, the performance of a Desolvator-K that was developed by the authors and two commercial coolers were investigated and compared in this study. Water vapor removal efficiency, recovery rate, and reproducibility of polar odorous compounds (i.e., methyl ethyl ketone (MEK), isobutyl alcohol (i-BuAl), methyl isobutyl ketone (MIBK), butyl acetate (BuAc), styrene) in air were taken into account. It was found that the Desolvator-K, the Cooler-G, and the Cooler-K showed 91.6%, 67.2%, and 62.1% water vapor removal efficiency, respectively, at the relative humidity of 90%. In terms of recovery rate, after water vapor removal devices, the Desolvator-K, the Cooler-G, and the Cooler-K revealed average recoveries of 96.6-103%, 81-101%, and 88.6-100%, respectively. Reproducibility of odorous compounds under all conditions of the Desolvator-K, the Cooler-G, and the Cooler-K were 5.94%, 31.2%, and 8.14% of relative standard deviation (RSD), respectively. Therefore, it is suggested that the Desolvator-K should be established as a water pretreatment device for the MEK, i-BuAl, MIBK, and BuAc compounds in the air.