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Thermionic Specific Detector
Cleaning/
Maintenance
When the TSD exhibits low sensitivity or high background noise,
cleaning is indicated. Visual inspection may also indicate a need for
cleaning. The ceramic bead, collector, or flame tip are all parts that are
deposit prone, depending on the type of samples being used. Clean
these parts as indicated in the following paragraphs.
Note: Always handle detector components with tweezers to avoid
contamination.
Bead Cleaning
Non-volatile deposits can be removed from the bead by gently scraping
the bead surface with a sharp tool or abrasive paper. The bead should
be supported while being cleaned to prevent bending the lead and
cracking the ceramic coating on the leads.
Flame Tip and
Internal Parts
Cleaning
Follow the steps below to clean the flame tip and internal parts.
WA R N IN G :
EYE HA ZA R D
WA R N IN G :
FIR E H A ZA R D
Use proper eye and skin protection.
Methanol and acetone are toxic and
flammable chemicals. Exercise appropriate
precautions when these chemicals are used.
1
Remove the detector and internal parts. Handle internal parts
with tweezers and place on a clean, uncontaminated surface.
2
Clean deposits from the surface of the collector with water or
abrasive paper.
3
Remove deposits which form on top of the flame tip by
scraping. If flame tip is plugged, clear by inserting wire
(approximately 0.012 inch diameter) into flame tip orifice.
4
Flush cleaned components with methanol and air dry.
Ferrule
Replacement
If a leak develops around the base of the flame tip assembly due to a
deteriorated ferrule or if the detector is to be operated at temperatures
above 350
°
C, and results in a crack, the ferrule must be replaced. A
leak at the ferrule may cause noise, instability, and loss of sensitivity.
Be sure to select the proper ferrule for the application. The Vespel
ferrule has a maximum temperature limit of 350
°
C.
