Contact Closure Problem of Waters UPLC and Thermo Orbitrap

[Roger_AO]

Hi,

We just installed a new Waters Acquity UPLC and connected it to a Thermo LTQ-Orbitrap. The issue is that sometime mass spec could not be triggered by UPLC., which means the gradient has already started but XCalibur still shows mass spec is "Waiting for contact closure". Sometime that happened at the beginning of a sequence. Sometime mass spec failed to be triggered in the middle of a sequence and the sequence would be blocked. Does anyone know what is the reason of that? How to prove if the contact closure device of UPLC is working fine or just broken? This issue really disturbed me a lot. Thanks a lot.

[DR]

1) Make certain that your wires are sell connected at both ends - give them a bit of a tug...

2) Make sure of what the Orbitrap needs re: contact closure. Some instruments are really picky about this.

3) If that's not what the "inj. start" portion of the Acquity terminal block provides, use one of the more configurable switches if the terminal block settings are not adjustable.

Good Luck