Determination of thiodiglycol in groundwater using solid-phase extraction followed by gas chromatography with mass spectrometric detection in the selected-ion mode

A highly sensitive analytical procedure is described for determining thiodi glycol in groundwater. Samples are initially fortified with 3,3'-thiodiprop anol (surrogate), then both species are extracted using sequential solid-ph ase extraction with both C-18 and Ambersorb 572 columns. The C-18 column, w hich removes extraneous groundwater components, is discarded; the Ambersorb 572 column is dried thoroughly before eluting polar components with a smal l volume of dichloromethane. The extract is taken to dryness using dry flow ing nitrogen, and the resulting residue is derivatized using N-(tert-butyld imethylsilyl)-N-methyltrifluoroacetamide and pyridine. The derivatized prod ucts are diluted to a final volume with toluene, chromatographed using a fu sed-silica capillary column, and detected with a quadrupole mass spectromet ric detector in its selected-ion mode. Two independent, statistically unbia sed, procedures were used to evaluate the detection limits for thiodiglycol ; the values ranged between 4 and 16 mug l(-1) groundwater. (C) 2001 Elsevi er Science B.V. All rights reserved.