Gas chromatographic approach for the determination of carbonyl compounds in ambient air

In this study, an effort was made to apply gas chromatography (GC) with a flame ionization detector (FID) to the determination of gaseous carbonyls (without derivatization) at sub ppb level. A GC system interfaced with a multi-function thermal desorber system (TD) was hence tested for the collection and analysis of gaseous carbonyls. During this study, the calibration properties of five carbonyl compounds – acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, and valeraldehyde – were evaluated by varying the operation conditions of the TD system (i.e., sample transfer approaches and sorbent types of cold trap). The results were generally discernible between compounds (light and heavy carbonyls) and/or between selected concentration levels. Most interestingly, the GC detection properties of the lighter aldehydes (acetaldehyde and propionaldehyde) varied significantly, as they were sensitively affected by the types of cold trap combination. However, the heavier aldehydes – butyraldehyde, isovaleraldehyde, and valeraldehyde – maintained highly constant trends for GC calibration. According to this study, a GC-based quantification of aldehydes can be completed by an optimized setup of TD system.