Miniature Sensors for Biological Warfare Agents using Fatty Acid ...

2.5.5. Additional Thermally-based Analysis Methods
2.5.5.1. Heated chemistry – Desorption / Vaporization
There is no technology currently commercially available that can perform both the
function of the heated reaction and the desorption/vaporization. Reaction or
derivative chemistry is usually performed separately from the analysis
instrumentation, and only a small volume of sample or extract is then used for the
analysis.
2.5.5.2. Thermal Desorption from Solids
Several companies sell laboratory-scale instruments for this purpose, including
Perkin-Elmer and Dynatherm. The sample is heated and those chemical species
released are usually trapped for further analysis. There are no portable or field
systems sold for this purpose.
2.5.6. History of pyrolysis / methylation
Table 14: History or pyrolysis / methylation.
Procedure Reference
conversion of TMAH salt of carboxylic acids
to methyl esters in GC inlet
methanolic solution of quat. amm. hydroxide
to produce methyl ester from triglyceride via
transesterification (must remain anhydrous to
prevent saponification)
whole cell + (not) tmah but
Trimethylphenylammonium hydroxide + curie
point pyro of whole cells – dubbed on-line
derivatization “OLD”
whole cell, demonstration of py-gc-ms
produces same FAME pattern as extraction
(lose hydroxy-substituted FA) and similar
repeatability
whole cell (or phospholipid) + tmah + curie
point pyro of whole cells
40
1963 [2]
1982 [53]
1989 [55]
1990 [27]
1991 [5]
first SPME deriv. in GC inj. 1997 [23]