How to acquire only PDA data on an LC/MS system controlled by MassLynx - WKB2415

OBJECTIVE or GOAL

Acquire only the PDA data on an LC/MS system controlled by MassLynx.

ENVIRONMENT

• MassLynx 4.1
• Quattro Series
• ACQUITY SQ/TQ/3100
• Xevo Series
• SYNAPT Series
• ZQ/EMD Series

PROCEDURE

1. Create a "dummy" MS channel as follows:
   1. Create an inlet method to acquire the appropriate PDA.
   2. Create a "dummy" MS Tune file with minimal allowed source temperature, desolvation temperature and desolvation gas flow rate
   3. Create a "dummy" MS method with a run time equivalent to that of the inlet method.
   4. In the "dummy" MS method, add a simple function to collect minimal data (example: single SIR or MRM transition with 0.1 s dwell time)
   5. In the MS method, go to Options > Method Events, under Initial Settings, set the Flow State to Waste to divert the flow away from the probe.
   6. Enter the inlet method, "dummy" MS method and "dummy" MS Tune file into their appropriate columns on the MassLynx Sample list.
      
      Technically, this setup will still acquire MS data. In a regulatory environment, you may need to have no MS data channel at all. In this case, do the following:
      Set the "dummy" MS method to acquire a minimal amount of data. Example: Single SIR with dwell time of 1 second, or very high data threshold or mass range that is out of the sample scope.RRRRein

ADDITIONAL INFORMATION

NOTE: This workflow applies to other detectors such as the TUV, Fluorescence, ELSD, etc. 

There are two additional alternatives, but are more "invasive" and more permanent solutions. 

1. Reinstall MassLynx with the option "No MS instrument" selected.
2. Or, use two MassLynx PCs—one with an MS instrument selected and one with no MS instrument—and switch between them depending on the analysis.