Chromatography Forum

Hi,

I'm tuning a SCIEX 2000 LC/MSMS. Positive mode worked out fine but in Negative mode I can only see one of the ions.

I am using NEG PPG 3 x10-4 calibration solution, undiluted. Infusing at a rate of 10 ul/min. I only see 45 amu when I should also be seeing 545, 933, 1223 and 1572.

Anyone encounter this problem and can offer some insight?

Thanks

I do not have api 2000 experience, just api 3/300/3000/4000.

What is your ISV? If it is too high you might get arcing in neg mode.
Infuse just "mobilephase" in Q1 mode (ms only) from say, 50 to 300 amu. (0.1 or 0.2 amu step , 1 msec dwell) or there abouts.
do you get a baseline?
Some parameters should change to the negative value of those seen in positive mode. I had an API-3 that did not switch these values automatically when I switched polarity because someone messed up the configuation file. (Config file now works). Perhaps there is something similar with the API 2000?

Alp