Simulated Detection of VCHs in Soil by Using a Self-made Electronic Nose

An electronic nose principally composed of a photo ionization detector (PID) was developed for rapid detection of volatile chlorinated hydrocarbons (VCHs) in contaminated soil. Interference gases such as benzene homologues were removed with a halogenated hydrocarbon RAE-SEP tube and the removal effect was estimated with gas chromatography (GC). Different concentrations of perchloroethylene (PCE) and trichloroethylene (TCE) gases were used to evaluate the precision and reproducibility of electronic nose by comparing with GC. On these bases, ventilation purification experiments of contamination soil were simulated with three typical paddy soils in Yangtze River delta region. Results showed that RAE-SEP tube was effective to remove interference gases, with 80~97% of benzene homologues being removed and at the same time more than 90% of VCHs passed through. With PCE or TCE gas, a linear dependence was derived between the data got by electronic nose and GC, the slope is near 1.0 and the correlation coefficient R2>0.99. Electronic nose showed data consistency with GC (R2>0.99, n=47)when used for soil ventilation process monitoring. Therefore, electronic nose is applicable for rapid determination of soil pollution by VCHs, improving the efficiency of pollution diagnosis and remediation.