Headspace-GC Determination of Halogenated Hydrocarbons in Water after Degradation Treatment by Nanomaterial

Headspace-GC was applied to the determination of volatile halogenated hydrocarbons (VCHs) as pollutants in water sample after degradation with nano-iron and nano-zinc. Conditions for headspace sampling were optimized and given as follows:1 gas-liquid ratio was 1:1, 2 equilibrium temperature was 80℃ and 3 equilibrium time was 50 min. Linearity ranges found for the 22 compounds were same between 50.0 and 1 000 μg·L^-1, with their detection limits (3S/N) ranged from 0.93 to 13.29 μg·L^-1. Recovery was tested at 3 concentration levels by standard addition method, giving values of recovery in the range of 85.6% to 125%. Values of RSDs (n=7) found were in the range of 0.12% to 4.4%. Degradation of VCHs by addition of either of the 2 nano-metals was observed. Taking trichloroethylene as example, after addition of the nano-metal, a removal rate over 90% was attained after 120 min, and a value near 100% was attained at 180 min. But matrix-enhancement effect was happened due to the addition of the nano metals, leading to high results of GC determination and also to under estimation of degradation effect.