User guide

300 Advanced User Guide
10 Detectors
How FID units are displayed in Agilent data systems and on the GC
The GC displays the FID signal in picoamperes (pA). The
following table lists how different data systems convert the
display units to reporting units.
To light the FID flame
Press [Front Det] or [Back Det], scroll to Flame, then press
[On/Yes].
To extinguish the FID flame
Press [Front Det] or [Back Det], scroll to Flame, then press
[Off/No].
Table 64 Properties of the FID
Property Value/Comment
Dynamic range 1 x 10
7
Sensitivity 10 to 100 picograms of an organic compound
dependent on the molecular structure.
Selectivity Responds to all organic compounds (C-H bonds)
except those which do not burn or ionize in the
hydrogen-air flame. There is little or no response for
H
2
O, CO
2
, CO, N
2
, O
2
CS
2
or inert gases.
Formaldehyde and heavily halogenated compounds
give minimal response.
Table 65 Unit conversions
Data system Height units LSV (height units) Area units Noise (ASTM)
*
Agilent data system 1 pA 1.3 x10
-4
pA 1 pA-sec 0.038 pA
SIGRange
†
01 x 10
-4
pA 1.3 x 10
-4
pA 1 x 10
-4
pA 0.038 pA
SIGRange 5 3.2 x 10
-3
pA 4.2 x 10
-3
pA 3.2 x 10
-3
pA 0.038 pA
Analog 1V
‡
1.25 x 10
-4
pA device dependent 1.25 x 10
-4
pA 0.038 pA
* Noise is recommended maximum when determining MDL.
† SIGRange used with 3393 and 3396 integrators.
‡ Analog 1V is an approximate value.