Table of Contents
Advertisement
Troubleshooting the MSD
3
Mass spectral symptoms
Mass spectral symptoms
This section describes symptoms you might observe in mass spectra. Some of
these symptoms will appear in the mass spectra of samples. Others you will
observe only in a tune report. Some of these symptoms have causes that can be
corrected by the operator. Others, however, require service by a Hewlett-Packard
service representative.
Two symptoms listed under Chromatographic symptoms: If sensitivity is poor
and If repeatability is poor, also apply to mass spectra.
Isotopes are missing or isotope ratios are incorrect
• Peaks are too wide or too narrow
• Scan speed is too high (scan mode)
• Dwell time is too short (SIM mode)
• Electron multiplier voltage is too high
• Repeller voltage is too high
• High background
• Dirty ion source
High background
• Pressure in the vacuum manifold is too high
• Air leak
• Contamination
High abundances at m/z 18, 28, 32, and 44 or at m/z 14 and 16
• System was recently vented (residual air and water)
• Air leak
Large peaks at m/z 14 and 16 are symptomatic of especially large leaks.
75
Advertisement
Table of Contents
