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CI Troubleshooting
3
Troubleshooting and Maintenance Manual
55
There should not be any peak visible at
m/z
32 (O
2
). This almost always
indicates an air leak.
Special NCI notes
Since NCI is so extremely sensitive, air leaks that are not detectable in EI or
PCI can cause sensitivity problems in NCI. To check for this kind of air leak in
NCI, inject OFN. The base peak should be at
m/z
272. If the abundance of
m/z
238 is much greater than that of
m/z
272, you have an air leak.
How do I find the air leak?
1
See
.
2
Look for the last seal that was disturbed.
•
If you just pumped down the MS, press on the sideplate to check for
proper seal. Poor alignment between the front analyzer and the GC/MS
interface seal can prevent the sideplate from sealing.
•
If you just replaced the reagent gas bottle or gas purifier, check the
fittings you just opened and refastened.
Figure 2
Looking for air leaks
Summary of Contents for 7000 Triple Quadrupole GC/MS
Page 24: ...24 Troubleshooting and Maintenance Manual 1 Introduction...
Page 50: ...50 Troubleshooting and Maintenance Manual 2 General Troubleshooting...
Page 122: ...122 Troubleshooting and Maintenance Manual 4 General Maintenance...
Page 144: ...144 Troubleshooting and Maintenance Manual 6 Vacuum System...
Page 182: ...182 Troubleshooting and Maintenance Manual 8 Electronics...
Page 213: ......
Page 214: ...Agilent Technologies Agilent Technologies Inc Printed in USA September 2009...