Thermo Electron Corporation
LTQ XL Getting Started
69
Chapter 4
Tuning with Your Analyte in
LC/ESI/MS Mode
This chapter provides information on tuning the MS detector in the
LC/ESI/MS mode using your analyte. You optimize the sensitivity of the
MS detector to your analyte through an automatic procedure.
The customized Tune Methods contained in your LTQ XL data system are
optimized for a wide range of applications, and they can be used without
further tuning of your MS detector. However, for certain applications you
might need to tune and optimize several MS detector parameters.
For instance, the most important parameters that interact with the ESI
interface and signal quality are as follows:
• Electrospray voltage
• Heated capillary temperature (voltage)
• Tube lens voltage
• Capillary voltage
• Sheath gas flow rate
• Auxiliary gas flow rate
• Sweep gas flow rate
The settings for these parameters depend on the solvent flow rate and target
analyte composition. In general, you should fine tune your MS detector
whenever you change the solvent flow rate conditions of your particular
application. In this procedure, you use the ESI low-flow Tune Method
ESImyTune.LTQTune
as a starting point, then further optimize the MS
detector parameters using an automatic procedure. The automatic
procedure adjusts the tube lens voltage, capillary voltage, and voltages
applied to the ion optics until the ion transmission of your analyte is
maximized.