Analysis of semi-volatile organics in aqueous process streams using solid-phase microextraction and gas chromatography

Analysis of aqueous streams contaminated with complex organic mixtures comm only used in industrial processes can be problematic. In this study, we des cribe the development of the solid-phase microextraction (SPME) headspace e xtraction technique in combination with gas chromatography (GC) to measure the leakage of n-decanol and Exxsol(R) D-110 (commercial solvent containing primarily napthenes and paraffins) into aqueous streams. These streams wer e derived from a continuous liquid membrane separator for the removal and r ecovery of Cr(VI) from industrial effluents. In one stream that was dilute in Cr(VI) at pH 2-3, a method giving good results for n-decanol analysis in volved the addition of n-octanol as an internal standard to GC calibration standards and test samples prior to SPME extraction with the appropriate ad justment of pH. The addition of 20 w/w% NaCl as an additional solute to all standards and test samples with pH adjustment was found to be successful f or quantitative determination of Exxsol(R) D-110. In a second stream that w as strongly alkaline and more concentrated in Cr(VI), GC calibration using standards containing NaOH and 300-500 ppm Cr(VI) gave satisfactory results for quantitative determination of both species. (C) 2001 Elsevier Science L td. All rights reserved.