Micromass Quattro Ultima, User Manual

Page: 149 / 227

The position of the probe is adjusted using the probe adjustment collar (in/out) and the
adjustment knob (sideways) located to the left of the probe. The two screws can be
adjusted singly or simultaneously to optimise the beam. The position for optimum
sensitivity and stability for low flow rate work (10 µl/min) is shown.
Small improvements may be gained by
varying the position using the sample and
solvent system under investigation. The
following information should be considered
when setting the probe position:
•
10mm of movement is provided in each
direction, with 1.25mm of travel per
revolution of the probe positioning
controls.
•
At higher liquid flow rates the probe tip
should be positioned further away from
the sample cone to achieve optimum stability and sensitivity. The position is less
critical than at lower flow rates.
Nebuliser Gas
Optimum nebulisation for electrospray
performance is achieved by fully opening
the
Nebuliser flow control valve, which is
situated on the instrument’s front panel.
Desolvation Gas
The desolvation gas is heated and delivered
as a coaxial sheath to the nebulised liquid
spray by the desolvation nozzle.
The position of the desolvation nozzle
heater is fixed relative to the probe
tip and requires no adjustment.
The Desolvation Gas flow rate is
adjusted by the control value situated on the instrument’s front panel. The optimum
Desolvation Temp
and flow rate is dependent on mobile phase composition and
flow rate. A guide to suitable settings is given below.
To monitor the flow rate, select the Source window on the tune page and
observe the
Gas Flows
readback window. The
Desolvation Gas
flow rate
indicated on the tune page includes purge gas (if enabled).
Electrospray
Page 149
Quattro Ultima
User's Guide
Desolvation
Gas Control
Nebuliser
Gas Control
Cone Gas
Control
8mm
4mm
Cone Gas
Nozzle
Probe
Tip