Advanced sample pretreatment for the monitoring of polycyclic aromatic hydrocarbons and extractable organic halogens in waste water. Flow based procedures with chromatomembrane cells

摘要

Polycyclic aromatic hydrocarbons (PAH) and extractable organic halogens (EOX) pollute industrial waste waters and need to be controlled continuously by automated procedures. Their sample pretreatment requires extraction first from complex matrices containing surfactants, humic acids, urine and electrolytes besides. When using chromatomembrane cells (CMC) for the extraction with pentane or hexane a flow based system can be established which preconcentrates the pollutants up to ratios of 100:1 at the same time. The extracted compounds become supplied to a gas chromatograph (PAH) using the split/splitless injection or to a combustion furnace (EOX), respectively. An aqueous solution later extracts the hydrogen halides from the exhaust gas for their simultaneous detection with an ion-chromatograph. The limits of lowest detection are attainable in the lower μg l~(-1) range by matrix adjusted calibration. The CMC is a novel device containing a bloc of biporous PTFE which enables the contact of two immiscible phases. Polar liquids fill the macropores whereas the micropores remain available for non-polar liquids or gases.