Specific analysis of trace organics in water using gas chromatography and mass spectroscopy.

For the characterization of a broad range of compounds in water, various methods have been combined into a procedure. The reliability and limitations of this approach have been discussed in this paper. This combined procedure represents only a preliminary solution to the problem of organic materials in water. Future improvements will be possible as new columns, instruments, and software become available. Physico-chemical constants of trace organic compounds have been used to predict and interpret their extraction and pre-separation in an analytical scheme where purge/trap and solvent extraction methods are combined to measure a broad range of organic materials. This approach is limited by the scarcity of thermodynamic data; such data must be generated if predictive models of pollutant behavior in analytical as well as environmental systems are to be developed. In summary, the basic requirements for analyzing trace organic compounds in tertiary effluents and drinking waters include: The analysis must be based on a small sample size (up to 1 liter). Samples of one gallon or more are costly to ship and difficult to process and store. Samples of one liter or less can be shipped at moderate cost and stored in medium-sized refrigerators. The detection limit for most trace contaminants must be in the lower nanogram per liter range. At detection limits of 1 microgram/l and above, the removal (or formation) of many contaminants cannot be determined precisely. For conclusive results, variabilities of the procedure, the compound, and concentration at a sampling point have to be considered and investigated. Generally, approximately 30 samples are needed to establish a concentration distribution (1).