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

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 15min and has a total weight of only 3kg, 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.