ONLINE ANALYSIS OF VOLATILE ORGANICS IN WATER USING HEAD SPACE GAS-CHROMATOGRAPHY - EVALUATION OF 5 HEAD SPACE TECHNIQUES

Many industrial effluent streams require monitoring for volatile organ ic carbon (VOC) at part per billion concentration levels. Head-space g as chromatography (GC) is a suitable on-line technique for this analys is (the VOCs are stripped from the water prior to analysis by GC). Thi s paper evaluates five dynamic head-space systems for sensitivity, lin earity, response time and simplicity. One of the head-space systems is commercially available while the other four systems were fabricated i n house. The thin-film head-space (TFHS) design was selected as the be st design for Dow Sarnia applications. This head-space system along wi th the associated sample system will be discussed in greater detail. T he TFHS system can easily measure VOCs at the 50 ppb concentration lev el, has a response time of less than 5 minutes and requires less than 4 hours per week routine maintenance. (C) 1996 Elsevier Science Ltd.