Abstract
Environmental monitoring of chemicals is important for risk evaluation. As almost all contaminants exist in water environments at very low concentration, appropriate concentration procedures are required. A nitrogen purge process has been used to concentrate extract containing various trace semi-volatile organic chemicals by combination with a solid-phase extraction. However, recovery loss is often caused depending on the purging conditions, and it decreases the reliability of the measurement. In this study, 166 chemicals of various physical properties were prepared and their recovery ratios were investigated under each condition. The recovery ratios in nitrogen purge were not necessarily determined by their physical properties, or overly influenced by the nitrogen purge volumetric flow rate. In contrast, the control of the solvent volume, which changes with the progress of the nitrogen purge concentration, was important in addition to the alternation of the final solvent from hexane to acetone, because the concentration of chemicals in the solvent was one of the key factors determining the recovery ratios in the nitrogen purge process. The variation of the recovery ratio was acceptably small under appropriately controlled conditions.
