How To Know When Your System Needs Maintenance - Thermo Scientific ISQ User Manual

How to Know When Your System Needs Maintenance

Table 1. Common Contaminants
Ions (m/z) To Monitor
13, 14, 15, 16, 17, 29, 41, 57
18, 28, 32, 44 or 14, 16, 19
69, 100, 119, 131, 169, 181, 214,
219, 264, 376, 414, 426, 464, 502,
576, 614
31
43, 58
78
91, 92
105, 106
151, 153
149
Peaks spaced 14 amu apart
Thermo Scientific
Typically, you will notice that your instrument needs maintenance when you are analyzing
your data on the computer. Some of the most common reasons and indications are as follows:
• Contamination—If you notice excessive background in your mass spectra, it is usually an
indication that your instrument is contaminated. Use the mass spectrum in the table
below to understand the origin of the contamination. If you notice cleaning solvent
peaks, it is usually an indication that your ion source cartridge was installed before it was
completely dried.
• Fingerprints—If you notice a series of mass peaks in your data that are 14 amu apart, it is
usually an indication of fingerprint or other hydrocarbon contamination. To avoid
fingerprints, you should wear clean, lint-free gloves when performing any type of
maintenance on a component in the vacuum manifold of the ISQ.
• Air Leaks—If you notice a higher than normal vacuum pressure or poor sensitivity, it is
usually an indication of an air leak. Check the last o-ring or ferrule you installed.
Compound
Methane
H O, N
2
PFTBA and related ions
Methanol
Acetone
Benzene
Toluene or xylene
Xylene
Trichloroethane
Plasticizer (phthalates)
Hydrocarbons
, O , CO or N, O
2 2 2
How to Know When Your System Needs Maintenance
Possible Source
CI gas
Residual air and water, air leaks,
outgassing from Vespel ferrules
PFTBA (tuning compound)
Cleaning solvent
Cleaning solvent
Cleaning solvent
Cleaning solvent
Cleaning solvent
Cleaning solvent
Use of vinyl or plastic gloves
Fingerprints, foreline pump oil, or other
hydrocarbons
ISQ User Guide
8
Troubleshooting
107