Ip. Mitov et La. Petrov, ASSESSMENT OF SOME POSSIBILITIES FOR IMPROVING THE PERFORMANCE OF GAS-CHROMATOGRAPHIC THERMAL-CONDUCTIVITY DETECTORS WITH HOT-WIRE SENSITIVE ELEMENTS, Journal of chromatography, 715(2), 1995, pp. 287-297
Citations number
6
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
The possibilities for improving the performance of gas chromatographic
thermal conductivity detectors (TCD) by using hot-wire sensitive elem
ents with appropriate design and increased resistance were studied. It
is shown that the design of the traditional TCD with one-way heat con
duction, and also the new kind of sensitive element design with two-wa
y heat conduction, in which one of the filament leads is assembled ins
ide the coil along its axis, can be optimized. The best TCD performanc
e can be achieved if the sensitive element spiral pitch is minimal and
the spiral radius is equal to r(c)/e in the case of one-way heat cond
uction and to the mean radius (r(c) + r(1))/2 in the case of two-way h
eat conduction, where r(c) and r(1) are the radiuses of the gas cavity
and of the central filament lead, and e approximate to 2.7 is the Nap
ierian number. Further, the optimization of the sensitive element desi
gn provides an increase in its resistance, which additionally improves
the TCD performance. Following this approach and taking into account
the ultimate capabilities of modern electronics, two new optimized des
igns of the sensitive elements with about 650 Omega resistance at 0 de
grees C, that after the numerical estimations presented could improve
the TCD performance more than tenfold, are developed and proposed for
further experimental studies.