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Performance characteristics of a new prototype for a portable GC using ambient air as carrier gas for on‐site analysis
Author(s) -
Sanchez Juan M.,
Sacks Richard D.
Publication year - 2007
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.200600367
Subject(s) - analytical chemistry (journal) , molecular sieve , gas chromatography , chemistry , parts per notation , capillary action , compressed natural gas , compressed air , flame ionization detector , desorption , chromatography , materials science , adsorption , composite material , organic chemistry
The performance characteristics of a portable GC instrument requiring no compressed gas supplies and using relatively lightweight transportable components for the analysis of volatile organic components in large‐volume air samples are described. To avoid the need for compressed gas tanks, ambient air is used as the carrier gas, and a vacuum pump is used to pull the carrier gas and injected samples through the wall‐coated capillary column and a photoionization detector (PID). At‐column heating is used eliminating the need for a conventional oven. The fused silica column is wrapped with heater wire and sensor wire so that heating is provided directly at the column. A PID is used since it requires no external gas supplies and has high sensitivity for many compounds of interest in environmental air monitoring. In order to achieve detection limits in the ppb range, an online multibed preconcentrator containing beds of graphitized carbons and carbon molecular sieves is used. After sample collection, the flow direction through the preconcentrator is reversed, and the sample is thermally desorbed directly into the column. Decomposition of sensitive compounds during desorption is greater with air as the carrier gas than with hydrogen.