Gas Chromatography/Mass Spectrometric Determination of Traces of Hydrophilic and Volatile Organic Compounds in Water after Preconcentration with Activated Carbon

摘要

The authors have developed an analytical method for extracting trace amounts of 15 hydrophilic compounds in water using gas chromatography/mass spectrometry coupled with an activated carbon preconcentration procedure. As internal standards, perdeuterated p-dioxane and N, N-dimethylformamide were added to 11 of a water sample; the water was passed through a granular activated carbon column. Organic substances adsorbed on the activated carbon were eluted with acetone and dichloromethane; the extract was then concentrated to 10ml with a Kuderna-Danish concentrator. Quantitative analyses using GC/MS with a selected ion monitor (GC/MS-SIM) were performed to measure the recovery efficiencies of the 15 compounds spiked into water samples at concentrations of 0.2 and 2.0μg/l. The recovery efficiencies through the internal standard method of the compounds, except alcohols and acetonitrile, gave more than 90% and their relative standard deviations were less than 7% at a concentration of 0.2μg/l. In this study, it was confirmed that the activated carbon preconcentration procedure is useful for extracting trace amounts of polar compounds which have a log P value (dichloromethane-water partition coefficient) greater than -0.5, except for compounds containing a hydroxy group or having a very small molecular weight. The method was applied to the analysis of river water and seawater for polar compounds. p-Dioxane, 1-propanol, N-nitrosodimethylamine, N-nitrosodiethylamine, N, N-dimethylformamide and N, N-dimethylacetamide were detected below the μg/l level.