INTERACTIVE EFFECTS OF TEMPERATURE, SALT CONCENTRATION, AND PH ON HEAD SPACE ANALYSIS FOR ISOLATING VOLATILE TRACE ORGANICS IN AQUEOUS ENVIRONMENTAL-SAMPLES

A systematic approach Is presented for the Isolation and quantification of volatile trace organics from aqueous solutions by head space analysis. Fundamental information is obtained on the partition process for a multiple solute system consisting of model compounds under varying aqueous matrix conditions, i.e., pH, temperature, salt addition. Interactive effects between parameters are quantitatively shown by the use of the thermodynamic equilibrium partition coefficient. A general optimum head space isolation methodology is obtained from statistical evaluation of the effect of parameter variation on the partition coefficient. The optimum head space analysis sampling conditions of pH 7.1, 50°C and 3.35 M sodium sulfate were determined from a statistical design. At the optimum conditions of this design, enrichment factors of the vapor phase of up to 66 times were achieved as compared to a reference state of pH 7.1, 30°C, without electrolyte addition. Under optimum head space analysis conitions, river and drinking water can be routinely profiled for volatile trace organics. © 1979, American Chemical Society. All rights reserved.