How to perform the gradient blank injection (for MassLynx)? - WKB81913

OBJECTIVE or GOAL

Acquire MS data without using the injector to investigate the cause of ghost peaks and carryover.

This makes it possible to figure out problems such as whether the cause of the ghost peak is on the injector side or the mobile phase or pump side.

ENVIRONMENT

• MassLynx
• ACQUITY UPLC H-Class
• ACQUITY UPLC I-Class

PROCEDURE

On the Inlet Method screen, change the start signal setting so that the injector won’t work when the run is started and the MS acquisition will be started.

1. Select Instrument Configuration from the Tools menu of the Inlet Method window.
2. When the Inlet Configuration window opens, click the Events & Triggering button.
3. When the Events and Triggering Wizard opens, click the Next button.
4. Remove all check marks from Event In (Be sure to note where the check marks were so that you can restore them.) .
5. Continue clicking the Next button several times and click Finish.

Perform the analysis with the above settings. (The injector won’t work when the analysis is started, and the MS acquisition will be started.)

ADDITIONAL INFORMATION

If the peak is detected from the analysis where the injector didn’t work, it is likely that the cause of the ghost peak is on the mobile phase or pump side instead of the injector side. Consider the following:

- Re-prepare the mobile phase (please also replace each solvent bottle, not just refill)
- Replace or clean the in-line filter of the pump
- Clean the pump body

Reference: Controlling Contamination in LC/MS Systems - Best Practices