Unstable lockspray signal with Xevo family QTof - WKB278436

SYMPTOMS

• LockSpray dropouts or LockSpray signal missing intermittently
• Unstable or no spray from reference probe
• After every refill of the reference syringe from reservoir B, it takes10 to 15 minutes for a stable LockSpray beam to appear

ENVIRONMENT

• Xevo G2-XS QTof/Tof
• Xevo G2-S QTof/Tof
• Xevo G2 QTof/Tof
• Xevo G3 QTof
• MassLynx
• waters_connect UNIFI
• UNIFI

CAUSE

Probably air within the MS fluidics path

FIX or WORKAROUND

1. Replace the wash solution content with 100% IPA and disconnect tubing from reference selector valve port 4.

                      Diagram will be slightly different for Xevo G3 mass spec products. Refer to the Fluidics tech ref document.

2. Perform at least three purges with the reference fluidics and confirm that the IPA is leaving the waste line accordingly without sputtering or air in the system.

3. Set reference fluidics to infuse at 20 µL/min and visually determine if you have fluid coming out.

4. If OK, reconnect the PEEK tubing (ID/OD, 0.004/0.0625 inches) at port 4 of the reference select valve and check again that fluid is coming out.

         Perhaps trim a few centimeters at each end of the black PEEK tubing.

5. Stop infusion and refill, and then check whether there is any delay. If yes, try to time how long that delay is.

6. If no delay, replace the 100% IPA with an MS-grade 50:50 water:methanol mix.

7- Purge the wash through the reference fluidics three times with the 50:50 water:methanol mix, and ensure that the mix issues from the waste line without sputtering or air in the system.

8. Place 100% IPA in the Reservoir B (where we expect the lockmass solution to be located), and purge the reference line three times.

9. Set the reference pump to flow at 5 µL/min and assess how the IPA is flowing out from the PEEK tubing.

10. If ok (without air bubble or sputtering), purge the reference fluidicsonce or twice with the relevant lockmass solution in use and reassess thr flow out of the PEEK tubing when it is set to 5 µL/min.

11. Assess the flow again and confirm that it is air-free.

If any issues appear from Step 8:

• • Locate the orange tubing (ID/OD 0.020/0.0625 inches, 680 mm of length) from the spare MS fluidics kit.
  • Disconnect the tubing from the reference select valve port 2.
  • With the spare tubing, you may bypass the access to reservoir B by creating another access to a reference solution container/bottle placed on the MS solvent tray.

ADDITIONAL INFORMATION