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No signal at negative mode

Posted: Thu Oct 15, 2009 2:30 am
by Jasmine
Dear All,

We are using an API2000 in our lab. Recently, we encountered a "weird" problem. During the tuning of a certain compound, we tried to do both positive and negative mode. Our signal with positive mode is very good. However, we didn't get a signal using the negative mode. Even running the solvent alone did not produce even a tiny bit of signal. Could you please advice what the probable cause could be? What should we do?

Appreciate any advice. Thanks!

Posted: Tue Dec 22, 2009 1:24 pm
by gmnydn
I suggest you to conduct diognostic tests for quadrupoles if there is of your instrument. There may be problems in DC energy ramps of Q1 and Q3 for negative mod.