Application of Flat Polymer Membrane Microextraction for the Continuous Detection of Trihalomethanes in Aqueous Matrices

Abstract

A module was developed for the continuous monitoring of volatile halogen organic pollutants in complex matrices. The module utilized a polymer membrane for extraction and a capillary gas chromatography-mass spectrometry (GC-MS) for detection. The extraction of analytes (CHCl3, CHCl2Br, CHClBr2 and CHBr3) from samples was performed in a flow system mediated by a non-porous flat membrane. The effects of the phase-volume ratios, flow conditions, kinetics, analyte properties and matrices were assessed and optimized. The limits of detection were at low mg L -1 to ng L -1 levels, with GC-MS analysis under selected ion monitoring (SIM), whereas enrichment factors between 6 and 30 were achieved. Precision values calculated as repeatability and reproducibility with a relative standard deviation (%RSD, n = 5) of 7.2 to 9.5 after 30 min were obtained. The performance of the continuous membrane assisted solvent extraction system was compared with classical liquid-liquid extraction. The method was applied to the extraction of trihalomethanes in chlorinated drinking-water samples.

Membrane-Based Extraction for Environmental Analysis

“…This gives LODs of 20-2000 ng l À1 , lower than the official US Environmental Protection Agency methods. 139 As mentioned above, 16 PAHs were extracted from water together with some OCPs leading to LODs of 2-47 ng l À1 . 135 Haloacetic acids were also determined by another research group, also using GC-ECD after two-phase LPME, and improved results were obtained compared with alternative extraction methods.…”