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The application of two total transfer valve modulators for comprehensive two‐dimensional gas chromatography of volatile organic compounds
Author(s) -
Lidster Richard T.,
Hamilton Jacqueline F.,
Lewis Alastair C.
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201000710
Subject(s) - analyte , thermal desorption , chromatography , chemistry , analytical chemistry (journal) , gas chromatography , injection port , desorption , diaphragm (acoustics) , adsorption , materials science , vibration , organic chemistry , composite material , physics , quantum mechanics
Rotary and diaphragm 6‐port 2‐position valves have been evaluated as modulators for comprehensive GC. A total transfer methodology was used such that all analyte materials from the primary column were passed to the second separating column. The transfer methodology used repeated short periods of stop flow, but retained good primary column performance since primary carrier flow was partially maintained as pressure equilibrated along the length of the first column. Highly resolved separations of complex samples such as petrol and essential oils were achieved with equivalent performance (in terms of second column resolution) to thermal modulation with flame ionisation detection (FID). The valve modulators tested could outperform thermal modulators for very highly volatile organic species since the modulation process was insensitive to analyte vapour pressure. The diaphragm valve tested showed the best performance and was incorporated with a thermal desorption system to provide a high sensitivity separation of volatile organic compounds (VOCs) in air with LODs for individual VOCs of 2–4 pptV for a 1‐L air sample.