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Chapter 14
Maintaining a Flame Photometric Detector
FPD Troubleshooting
Sensitivity
The FPD sensitivity is affected by the temperature. The FPD response decreases
with an increase in the detector temperature. In addition, the detector response can
be severely reduced if a non-sulphur or non-phosphorus compound is partially or
fully eluted with the analyte of interest (quenching).
Keep clean the interferential filter and the heat shields as described in the
maintenance sequences, to avoid reducing sensitivity. Replace the heat shields if
the deposits due to contamination cannot be eliminated.
Gases
A right choice of the flow rates of hydrogen and air (fuel gases) is of primary
importance in determining FPD sensitivity. Flow rates will affect also selectivity
and, to a great extent, peak shapes.
Optimum carrier gas flow rate depends on the type of gas used and on the
diameter of the column installed.
The gases normally used with FPD are reported in the Table 14-3
310
Carrier gas
Capillary Columns
Packed Columns
Helium
Helium
Nitrogen
Nitrogen
Hydrogen
Argon
Table 14-3.
Gases used for FPD
Fuel gas
Hydrogen + Air
FPD Troubleshooting
Make-up gas
Generally not
required
Maintenance and Troubleshooting Manual
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