Chromatography Forum

QUATTRO MICRO API troubleshooting

"Turn LC pump off" is a part of my shutdown method. It usually works fine at the end of the sequence. But sometimes my sequence pauses in the middle (for no reason...), and when shutdown method is activated "at pause" as planned, it does not turn off the LC pump. Several times my probe compartment looked like a 1/3 full aquarium. It was not this high to damage my instrument, but overall this is a problem. I wonder if anyone has had similar experience, and found a remedy? So far Waters does not know either. I was thinking along the lines of minor and occasional power spikes interrupting LC -- MS communications... but this may not be the reason. Looking for an advice.

Does Masslynx generate an error message when the sequence gets stuck or do you just get a "Not ready" notification?
Does this usually happen between two runs or does it randomly abort a run somewhere in the middle?

If it always happens when switching from one run to the next, then you could use the divert valve to direct the flow into the waste at the end of a run and redirect it back to the ion source at the beginning of the next run. You can use the method events in the MS method for this. However, be aware that there are some Quattro Micros out there that have some problems with the divert valve (i.e. it might not switch properly).

Depending on your Masslynx version and the SCN there is also the possibility to run the "shutdown on error". This includes options like "MS error", "MS Comms Error" or "Inlet fatal error" which can trigger a shutdown if the communication gets lost. Of course, if you have a "MS Comms Error" the shutdown tasks of the MS (like "Standby" or "Switch API gas off") are not executed anymore, however the commands for the components that are responding are still executed.

When you say your source compartment looked like an aquarium, it means that the shutdown was partially activated as the MS switched into standby, correct?
If this is the case, this implies a communication problem with the LC pump. Then you can use the above mentioned "Inlet fatal error" but define a different shutdown for this scenario that does not put the MS into standby. This won't stop the pump, however at least the MS will continue to evaporate the flow.