Preventive Maintenance
Flame photometric detector
Caution
Failure to turn off the TCD and to cap the detector column fitting may cause irreparable damage to the filament due to O2 entering the detector.
3.Establish normal reference gas flow rate (20 to 30 ml/min) through the detector (set oven temperature to 250^C).
4.Heat the detector to 400^C; allow thermal cleaning to continue for several hours.
Flame photometric detector
Cleaning/replacing FPD windows, filters, seals
Column bleed and/or effluent can contaminate the first quartz window (heat shield) nearest the detector module. Dust, fingerprints, atmospheric contaminants can dirty both quartz windows, the filter, and/or the photomultiplier tube (PMT) window. Contamination anywhere along the light path between flame and PMT can reduce detector sensitivity.
Turn the detector off.
Turn off hydrogen, air (or oxygen), and auxiliary nitrogen supplies to the detector (manifold on•offvalves); for convenience, carrier flow and other temperature zones may be left on and at their respective setpoints. Allow time for the detector module to cool.
Remove the PMT assembly from the detector module and remove the filter. Use lint•freelens tissue to clean the filter (both sides) carefully, and the PMT window seen inside the housing. Be careful not to scratch surfaces; do not use any cleaning fluid that might leave a film upon drying.
Inspect the filter; chips, scratches, and/or cracks in the light path scatter light, reducing detector sensitivity. Replace filter(s) as necessary (sulfur mode filter, Part No. 19256•80000;phosphorus mode filter, Part No.
19256•80010).
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