User guide

60 Multimode Source for 6100 Series Single Quad LC/MS User Guide

3 Reference

Guidelines for multimode source settings in MM-ES+APCI mode

Drying gas flow Always set to 5 L/min (IR does the drying)

Nebulizer pressure Start at 40 psi. You will use the nebulizer pressure and the

corona current to balance ESI and APCI. A higher nebulizer pressure results

in more ESI. A lower nebulizer pressure results in more APCI.

Drying gas temperature Set to 300°C. Remember you want the vaporizer to

control the drying and to be able to maintain the set point.

Vaporizer Start at 200°C. A higher temperature usually works better for

MM-APCI. MM-ESI is usually unaffected except for sodium adduction. The

vaporizer will compensate for flow rate or solvent composition.

Capillary Voltage Set to 2000 V. A lower voltage works better for fast

switching. You are balancing ESI and APCI response. A setting of 2000 is a

good compromise.

Corona current Set to 1 µA for positive or negative polarity. More corona

current will reduce the ESI signal and increase the APCI signal.

Charging Voltage Set the charging voltage to 2000 V.

NOTE

Click Instrument > MSD Spray Chamber to set the Method Spray Chamber to

MM-ES+APCI before you edit the Set Up MSD Signals dialog box.

NOTE

The above set of parameters is provided as a starting point and should yield good response

for many analytes. To obtain a specific response, i.e., high sensitivity detection of a

compound or class of compounds, or a balanced response to a wide variety of compound

classes, these parameters and the LC mobile phase composition should be examined

further using traditional techniques for optimizing a method.