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Temperature‐programmed desorption for membrane inlet mass spectrometry
Author(s) -
Ketola Raimo A.,
Grøn Christian,
Lauritsen Frants R.
Publication year - 1998
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19980630)12:12<773::aid-rcm231>3.0.co;2-d
Subject(s) - chemistry , adsorption , desorption , mass spectrometry , membrane , analytical chemistry (journal) , chromatography , toluene , helium , volatile organic compound , organic chemistry , biochemistry
We present a novel technique for analyzing volatile organic compounds in air samples using a solid adsorbent together with temperature‐programmed desorption and subsequent detection by membrane inlet mass spectrometry (TPD‐MIMS). The new system has the advantage of a fast separation of compounds prior to the detection by MIMS. The gaseous sample is simply adsorbed on the adsorbent, which is then rapidly heated from 30 °C to 250 °C at a rate of 50 °C/min. Trapped organic compounds are released from the adsorbent into a helium stream at different temperatures depending on the strength of the interaction between the individual compound and the adsorbent. The helium stream carries the desorbed compounds to a membrane inlet (90 °C) equipped with a thin (25 μm) silicone membrane. The thin membrane and the high temperature of the membrane inlet allows most volatile compounds to diffuse through the membrane into the mass spectrometer in a few seconds. In this fashion we could completely separate many similar volatile compounds, for example toluene from xylene and trichloroethene from tetrachloroethene. Typical detection limits were at low or sub‐nanogram levels, the dynamic range was 3 orders of magnitude, and the analysis time for a mixture was about 3–4 minutes. © 1998 John Wiley & Sons, Ltd.