G I M E
GAS INJECTION MEMBRANE EXTRACTION (GIME) FOR MEASUREMENT OF VOCS IN WATER
of volatile organic compounds (VOCs) in water usually involves a
separation step in which the organics are first extracted from the matrix.
Popular analytical techniques used for VOCs analysis are
these methods first isolate the organics from water prior to analysis by
GC or GC/MS.
In GIME, there is no mixing between the carrier gas and the aqueous sample, thus eliminating sample dispersion within the carrier. The gas also cleans the membrane surface after the sample is pushed through the membrane module. This reduces the static aqueous boundary layer effects that cause long lag time in the extraction profile. Fig. 2 is a comparison of membrane extraction profile of GIME with that of aqueous elution, which shows that GIME extraction is much faster while maintaining the same sensitivity. A chromatogram obtained by GIME from a water sample containing ppb level of VOCs as specified in EPA method 602 is shown in Fig. 3.
ADVANTAGES OF GIME
On-Site And On-Line Analysis Of Chlorinated Solvents In Ground
Water Using Pulse Introduction Membrane Extraction Gas Chromatography (PIME-GC).
San Juan, A.; Guo, X; Mitra, S. J. Sep. Sci.
24(7), 599-605 (2001).
analysis of non-steady-state, pulse introduction membrane extraction with
a sorbent trap interface for gas chromatographic detection, Guo, X.; Mitra,
S. Anal. Chem. 71(20), 4587-4593
Enhancement of Extraction Efficiency and Reduction of Boundary
Layer Effects in Pulse Introduction Membrane Extraction. Guo, X.; Mitra, S. Anal. Chem.
71, 4407-4413 (1999).
Pulse introduction membrane extraction for analysis of VOCs in
individual aqueous samples and for continuous on-line monitoring, X. Guo
and S. Mitra, J. of Chromatogr. A, 826, 39-47 (1998).
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