7 General Maintenance
To Clean an EI XTR, SS, or Inert Source
5977B Series MSD Operating Manual 207
Procedure
1 If the contamination is serious, such as an oil backflow into the analyzer,
seriously consider replacing the contaminated parts.
2 Abrasively clean the surfaces that contact the sample or ion beam.
Use an abrasive slurry of alumina powder and reagent-grade methanol on a
cotton swab. Use enough force to remove all discolorations. Polishing the
parts is not necessary; small scratches will not harm performance. Also
abrasively clean the discolorations where electrons from the filaments
enter the source body.
3 Rinse away all abrasive residue with reagent-grade methanol.
Make sure
all abrasive residue is rinsed before ultrasonic cleaning. If the
methanol becomes cloudy or contains visible particles, rinse again three times.
4 Separate the parts that were abrasively cleaned from the parts that were not
abrasively cleaned.
5 Ultrasonically clean the parts (each group separately) for 15 minutes. For
dirty parts, use all three solvents in the order shown, cleaning 15 minutes with
each of the following solvents:
• Methylene chloride (reagent-grade)
• Acetone (reagent-grade)
• Methanol (reagent-grade)
For routine cleaning, cleaning with methanol is sufficient.
6 Place the parts in a clean beaker.
Loosely cover the beaker with clean
aluminum foil (dull side down).
7 Dry the cleaned parts in an oven at 100°C for 5–6 minutes.
The filaments, source heater assembly, and insulators cannot be cleaned
ultrasonically. Replace these components if major contamination occurs.
All of these solvents are hazardous. Work in a fume hood and take all
appropriate precautions.
Let the parts cool before you handle them.
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