Table of Contents
Advertisement
Table 3
Common contaminants
Ions ( m/z )
18, 28, 32, 44 or 14, 16
31, 51, 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
69
73, 147, 207, 221, 281, 295,
355, 429
77, 94, 115, 141, 168, 170,
262, 354, 446
149
Peaks spaced 14 amu apart
Compound
H
0, N
, O
, CO
or N, O
2
2
2
2
PFTBA and related ions
Methanol
Acetone
Benzene
Toluene or xylene
Xylene
Trichloroethane
Foreline pump oil or PFTBA
Dimethylpolysiloxane
Diffusion pump fluid and
related ions
Plasticizer (phthalates)
Hydrocarbons
Troubleshooting the MSD
3
Contamination
Possible source
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
Foreline pump oil vapor or
calibration valve leak
Septum bleed or methyl
silicone column bleed
Diffusion pump fluid
Vacuum seals (O-rings) damag-
ed by high temperatures, vinyl
gloves
Fingerprints, foreline pump oil
91
Advertisement
Table of Contents
