Fpd - Agilent Technologies 8890 Operation Manual

5 Methods
Table 5
Gas type
Detector gases
Hydrogen
Air
Column plus capillary makeup (N
recommended, or He as an alternative)
Detector Temperature
If < 150 °C, the flame will not light. Agilent recommends a temperature 300 °C to prevent
condensation damage. The detector temperature should be approximately 20 °C greater than
highest oven ramp temperature.
* The hydrogen / air ratio should be 8% to 12% to keep the flame lit

FPD+

The sample burns in a hydrogen- rich flame, where some species are reduced and excited. The
gas flow moves the excited species to a cooler emission zone above the flame where they
decay and emit light. A narrow bandpass filter selects light unique to one species, while a
shield prevents intense carbon emission from reaching the photomultiplier tube (PMT).
The light strikes a photosensitive surface in the PMT where a light photon knocks loose an
electron. The electron is amplified inside the PMT for an overall gain of up to a million.
Storage
The FPD+ should not be stored at temperatures above 50 °C.
FPD+ linearity
Several mechanisms produce sulfur emission. The excited species is diatomic, so that
emission intensity is approximately proportional to the square of the sulfur atom
concentration.
The excited species in the phosphorus mode is monatomic, leading to a linear relationship
between emission intensity and atom concentration.
Inlet liners for use with the FPD+
Compounds containing sulfur may adsorb on an inlet liner and degrade the GC's performance.
Use deactivated, clean liners or a cool on-column inlet, which injects directly onto the column.
For best results use Agilent Ultra Inert liners:
•
•
FPD+ temperature considerations
The FPD+ provides two temperatures zones, one for the transfer line (the main detector
temperature) and one for the emission block. For the transfer line temperature, we
recommend a temperature that is 25 °C higher than the highest column temperature.
90
Recommended starting conditions (continued)
is
2
Splitless 5190-2293
Split 5190-2295
Suggested flow rate
*
40 mL/min
*
450 mL/min
*
50 mL.min
Operation Manual