by
lmh » Thu May 05, 2022 12:29 pm
Shimadzu instruments continue to do, at the end of a batch, what the last method was doing. There are therefore various things you can do to stop the system.
(1) If you don't care in what state you want to leave your column, you can just tick the boxes for shutdown in the batch settings.
(2) If you do care, you can write a method using the spare solvent channels to put an appropriate solvent through the column for as long as you want... and...
(3) In all cases, you can write a "stop" method with zero pump flow, deuterium lamp turned off, and whatever other conditions you want.
You can then list these methods at the end of your batch. In fact this approach avoids using the batch settings at all, while giving you complete control over the instrument. If you put the wash method second to last, and the stop method last, then your wash method will do all the washing, with detectors turned on so you can check whether you actually washed anything off, and the stop method will run, turn the flow to zero and leave the autosampler cold, whatever else you want - and the following morning, the instrument will still be "on" and "pumping", except it's pumping at a flow-rate of zero, with all the detectors turned off.
The down-side of this is that anyone trying to purge the pumps the following morning needs to be aware that pressing buttons on the pump won't do anything (because so far as the pump is concerned, it's on and pumping, under software-control), so the pump needs to be turned off. And if anyone sets a flow the following morning, it will happen straight away. And the biggest problem: if tomorrow's user is setting up a method and forgets to start a new one, next time you try to use your "Stop" method, you find it's now someone else's "Go" method!