Discharge in the negative mode on the Capillary LC-MS
Posted: Tue Nov 16, 2010 5:56 am
Hi
I've met a discharge problem on a capillary LC-TOF MS. The MS instrumentation is ABI Qstar. When the metabolite standards in water with 0.1% formic acid was infused into MS for tuning, there was a discharge at the tip of the frit in negative scan mode (the ionspray voltage was only -1500) and the MS signal response was unstable. To solve the discharge, the voltage had to be reduced to -1300 at the expense of loss of signal sensitivity. And the signal was still not stable even in this low voltage condition. However the same sample didn't get any discharge in the positive scan mode.
Does anyone have an idea to solve this problem?
Thanks a lot!
I've met a discharge problem on a capillary LC-TOF MS. The MS instrumentation is ABI Qstar. When the metabolite standards in water with 0.1% formic acid was infused into MS for tuning, there was a discharge at the tip of the frit in negative scan mode (the ionspray voltage was only -1500) and the MS signal response was unstable. To solve the discharge, the voltage had to be reduced to -1300 at the expense of loss of signal sensitivity. And the signal was still not stable even in this low voltage condition. However the same sample didn't get any discharge in the positive scan mode.
Does anyone have an idea to solve this problem?
Thanks a lot!