•
•
DETector Engineering
&
Technology, inc.
486 N.Wiget Lane,Walnut Creek, CA 94598 USA
DEl
telephone: (925) 937-4203
fax: (925) 937-7581
e-mail : DETplp@aoLcom
innovations in chemical detection
THERMIONIC SURFACE IONIZATION DETECTION
FORGAS CHROMATOGRAPHY (GC)
unprecedented capability for interchange betweenmultiplemodes
of
selective
chemical detection using low cost, uncomplicated detector equipment
basic detector components:
an electrically heated, ceramic ion
source cylinder is positioned on the
axis of a collector cylinder
THERMIONIC IONIZATION DETECTOR DESIGN
(CONCENTRIC CYLINDERGEOMETRY)
Ion Collector
Cylinder
Ceramic
Ion Source
(1/16 in. dia.)
I
•
I
I
I
I
Gas 2
J
(Air,
N 2)
r
i
~~
Sample Inlet
:
L
Gas
2
I
I
I
L
Sample & Gas
1
&
Makeup
(Gas
3)
(H
2 ,
N
2 •
Air)
basic detector science:
samples extract electrons from the
ion source to form negative ions
which are measured at the collector
selectivity/sensitivity determined by:
1. chemical composition of the ion
source ceramic;
2. temperature of the ion source;
3. composition of the gas
environment about the ion source;
4. magnitude of the polarizing
voltage between the ion source and
collector electrode;
multiple modes of
achieved using the
equipment, a choice
ceramic ion sources,
detection are
same basic
of 8 different
and various
permutations of these 4 operating
parameters.
SELECTIVITYCHOICES INCLUDE COMPOUNDS CONTAINING N, P, 0, CI, Sr, I,
Pb, Sn, OR Si ATOMS, OR N0
2 ,
PYRROLE, CH
2 ,
AND CERTAIN OTHER
FUNCTIONALGROUPS.
THERMIONIC DETECTORS OFTEN REVEAL TRACE SAMPLE CONSTITUENTS
NOT DETECTEDBYOTHER TYPEGCDETECTORS.
Website :
E-mail :
TelNo : 03 9762 29034 . . . inAUSTRALIA
