Detector Chemical Contamination - Thermo Scientific TRACE 1600 Hardware Manual

4
Performing Detectors Routine Maintenance
Maintaining an Electron Capture Detector (ECD)

Detector Chemical Contamination

182 TRACE 1600/1610 Hardware Manual
WARNING All the operations must be carrier out at low temperature to avoid burns.
Therefore, before conducting maintenance, cool the detector to room temperature.
Materials needed to maintain an ECD detector
Ultrasonic cleaner
GC-grade hexane
GC-grade toluene
Fine emery paper
Little flathead screwdriver
T20 Torxhead screwdriver
Forceps or tweezers
Collecting electrode (Anode) if necessary
The ECD, if properly used, has a good resistance against chemical contamination. However,
some critical operating conditions may cause, over time, contamination of the collecting
electrode (anode). This contamination is highlighted by an excessive increase of the base
frequency, and a baseline drift when the reference current or the pulse amplitude is changed.
The collecting electrode can be easily removed and cleaned without disturbing the radioactive
source.
Detector contamination could be indicated by the following effects in the chromatogram:
• Reduced signal to noise ratio
• High-noise baseline (high frequency)
• Baseline drift with changing pulse voltage
• Negative dips after peaks
If chemical contamination of the whole cell is suspected proceed as follows:
1. Heat the ECD at the maximum operating temperature with carrier and make-up gases
flowing through the detector (thermal cleaning).
2. Follows the decontamination process by monitoring the base frequency. Initially the
frequency value tends to increase to very high values, and then it decreases to acceptable
ones.
If irreversible contamination of the cell is suspected please contact your local Thermo Fisher
Scientific Technical Service office.
Thermo Scientific