Measuring real-time concentration trends of individual VOC in an elementary school using a sub-ppb detection μGC and a single GC–MS analysis

• A field study of real-time analysis of ambient VOCs in an elementary school located adjacent to a chemical plant.
• TO-15 analyses were used to determine the VOC species and representative concentration level.
• A μGC recorded the real-time field chromatograms and calibrated at low ppb level.
• Real-time concentration trends of individual chemicals allowing the observation of correlations between compounds.

This paper reports the results from a field study that used a micro gas chromatograph (μGC) in conjunction with single gas chromatography-mass spectrometry (GC–MS) analysis to obtain the time-dependent concentration changes of individual volatile organic compounds (VOCs). The μGC is capable of performing sub-ppb analysis every 15 min and has a total weight of only 3 kg, which includes an embedded tablet computer. The field study was conducted in an elementary school near a chemical industrial area. Six VOCs including acetone, 2-butanone, methyl acetate, toluene, m-xylene and isobutyl acetate, were detected at low ppb levels via canister/GC–MS analysis. Five of the six chemicals were successfully quantified using the μGC. The lone exception was acetone, which prematurely breakthrough on the preconcentrator of the μGC because of its high volatility. The continuous analyses performed by the μGC revealed the individual temporal trends of the concentrations for the remaining 5 chemicals. The establishment of real-time trends for each of the chemicals enabled a detailed examination of their correlations.