Journal of Chromatography A, 896 (2000) 31-39 Cryogen free automated gas chromatography for the measurement of ambient volatile organic compounds Journal of Chromatography A, 896 (2000) 31-39 Jia-Lin Wang*, Wei-Li Chen, Yen-Hung Lin, Cheng-Hsiung Tsai

experimental HP6890-Dual traps, FID PLOT for C3-C7 30m × 0.32mm ; 8 μm. DB-1 for C6-C12 60m × 0.32mm ; 1 μm. Uncoated column 5 m × 0.25 mm

C3-C7 NMHCs in Taiwan EPA monitoring station 1th 250th 673th

preconcentration system

Minimizing longitudinal diffusion 0.5mm ID × 1.6mm Non- Cooling GC oven 0.5mm ID × 1.6mm Cooling GC oven

0.5mm ID × 1.6mm Cooling GC oven 0.25mm ID × 0.8mm Non-Cooling GC oven

Reproducibility

Linearity Propane from PLOT column Flow rate = 50ml / min Benzne from PLOT column Flow rate = 50ml / min

(a) CO by NDIR (b) Benzene by automated system

R2> 0.92 R2> 0.25

conclusion This work was to build an automated GC system for measuring VOCs either in the lab or the field without using cryogen in preconcentration and column separation. Two traps were coupled to their designated columns to form suitable pairs to provide adequate resolution without cryogen use.