|
The
FPD detector is similar to the FID except that the detector body is completely
light tight and a second flow of hydrogen purges the optical path between
the photomultiplier tube ( PMT ) and the hydrogen-rich flame. A bandpass
filter at 393nm. for sulfur or 525nm. for phosphorus mounts in front of
the PMT so only the emissions from sulfur or phosphorus are detected while
other wavelengths are rejected. While not 100% selective, the FPD
is 100,000 times more sensitive for S-P compounds than for hydrocarbons.
Sulfur compounds such as H2S or SO2 can be detected down to about 200 ppb
and phosphorus to 10ppb. The phosphorus response is linear, but the
sulfur response is exponential ( twice the sulfur yields four times the
peak area ). The dual FPD detector is equipped with two PMTs which allow
simultaneous detection of sulfur and phosphorus. Either the single
or dual FPD can be equipped with an FID collector electrode and electrometer
which will detect the hydrocarbon peaks at the same time as the PMTs are
responding to the S-P compounds. The FID response is not as sensitive
as a pure FID because the hydrogen-rich flame required for optimum S-P
detection is not optimum for best hydrocarbon response. Users can
easily optimize S-P response versus hydrocarbons response by simply adjusting
the hydrogen/air mixture using the included EPC gas controls.
8690-0080 Single FPD detector with
EPC gas controls $3,995.00
8690-1080 Single FPD as above with
FID collector electrode and
dual amplifiers
$4,995.00
8690-0085 Dual FPD with EPC gas controls,
dual amplifiers and PMTs $7,995.00
8690-2085 Dual FPD as above with FID
probe and
three amplifiers
$8,995.00
|
|
