A Continual Flow System for Detection of VOCs in Industrial Waste Water

摘要

An automatic continual sampling device connected with Purge&Trap-GC-FID system was developed for real-time monitoring of VOCs in wastewater discharged from high-tech industries, The system was designed to simultaneously monitor 17 compounds, including one polar compound, acetone, and 16 non-polar compounds. The trapping tube was packed with two adsorbents, carbopack B and carbosieve III, to trap the target compounds. For the purpose of in-situ monitoring, the flush of sampling tube composed of two two-way valves and one time controller to prevent the absorption interference of the residual. The optimum condition for the analytical system was 12min of purge time at 60°C (purge temperature) and 4min of desorption time at 260°C (desorption temperature). Good chromatograms were obtained with the developed analytical system even if cryogenic device and de-mist process were not used. The precision was high (RSD 1.99%~13.35%) and the accuracy was achieved at the level between 0.27% to 23.54%. The method detection limits ranged from 0.32 to 2.39 ppb.