Chromatography Forum

Hi All,

I am trying to create a shutdown method for an alliance 2695 system in Empower 2. I currently have a method that shuts off the column heater and UV lamp, washes the column with methanol, and then sets the flow to zero. I have three issues/questions:
1. Is there a way to shut down the in-line degasser at the end of the method? The only solution I have been able to come up with is to have a second shutdown method which turns the in-line degasser off.
2. Does setting the flow rate to zero shut off the needle wash solvent?
3. Is this the best/correct way to go about shutting down the instrument after an analysis?

Thanks.

1. Is there a way to shut down the in-line degasser at the end of the method? The only solution I have been able to come up with is to have a second shutdown method which turns the in-line degasser off.

? don't know yet, have to take a look at it when in the lab again.
Maybe by an "Event" in the Instrument method?
Beside this, I wouldn't concern to have the whole shutdown procedure run without the degasser turned on.
Otherwise I guess you'll need to methods, yes.
On our UPLC with column manager we also do it by two methods, one is for the flushing of the columns and set within the sample set, and the second (real shutdown) slows down the flow and set the column selector valve to a bypass position and is choosen as "Shutdown method" in the "run samples" dialog-box.

2. Does setting the flow rate to zero shut off the needle wash solvent?

How do you wan't to turn this off?
Needle wash pump is only active just after an injection, so no need (and possibility) to programm anything here.

3. Is this the best/correct way to go about shutting down the instrument after an analysis?

I don't know, if it's the "best" way to do it but we proceed just similar
flush the column, turn of the lamp, set the flow to zero.
We don't care about the degasser (leav it on), normally it doesn't take too long until somebody will walk on to the system and power off (longest would be a weekend). Never had problems about that.
Before power off, it would be a good practice to purge also the injector with methanol, as there is still your inital mobile phase in the syringe and lines.
Do this before you remove the column, because you need some backpressure for propper purging the inj.
Therefore you could also add this function at the end of your sample set.

eg.
- equilibrate or condition column (->system/column to methanol); flush method 1
- purge inj; flush method 1 (or new one, depending on inital conditions)
- shutdown method

Disagree on degasser - it is best to just run your washout method w/ degasser disabled. Then it stays off when it is not needed.