Standby method

I typically run samples at various times throughout the day on my UPLC and prefer to have a single sequence file per day. To achieve that I include a standby method with a low flow rate at the end of my samples that runs for multiple hours until I add more samples to the sequence. I have several of these in the sequence so the LC could theoretically run "indefinitely" until I add more samples.

I switch from the standby method to any newly added samples via "Instrument" >> "Set up Instrument method" and change the run time (stop time in binary pump menu) to something like 0.1 min. In the past, I would have multiple standby runs throughout the day without any issues.

However, I recently moved to a new instrument and when ending the standby method as described above via "Set up instrument method", it also changes the run time for any later standby runs in the same sequence, while previously this only changed the run time for that specific standby run.

Does there exist a setting where changing the method via "set up instrument method" during the sequence run only changes the run time of the currently running method (in this case, the standby method), but not any later runs with the same standby method?

  • Hello,

    Can you say what software and version you are using? It sounds like Chemstation but I would like to confirm that and find out what version. Also did the software version change between the instruments?


  • Yes, Agilent OpenLab CDS ChemStation Edition. I need to double-check the previous instrument, but pretty sure there are some minor differences between the instruments in terms of software.

    This is the one I am currently using.

  • Hello,

    Can you provide the CS version? You should be able to see this screen under the help menu item under about. 

    Marty Adams

  • Hi UPLC-user,

    I’ve confirmed what you are seeing using OpenLab C.01.10 connected to a 1260 system.  It appears that when the standby method ends it save a new copy of the altered method to the sequence and then the sequence uses that copy instead of the method copy from the master method directory.

    One way around this would be to use a macro to copy the standby method from the master directory to the sequence directory.  This is a bit of a cludge but should work just fine.   Below is a macro that will accomplish this.  I’ve tested it and it works as intended.  In the code below the standby method I used is named "STANDBY-AB.M".

    If you’ve never worked with Openlab macros just place this code in a User.mac file in the Core directory. Copy  CPRequest STANDBYCP, "STANDBY_RESET" to the “Runtime Checklist” under “Post-Run Command / Macro”  Then run your sequence as normal.

    Let me know if you need any help.



    CPStart STANDBYCP                                                                                        !----INITIATE SEPERATE PROCESS

    !--           CPRequest STANDBYCP, "STANDBY_RESET"                                        

    !----RUN MACRO IN SEPERATE PROCESS, add above line to the Runtime Checklist post method command / macro section



                    SLEEP 20                                                                               !----Give some time for the sequence to move to next sample

                    Delete _methpath$ + "STANDBY-AB.M", DONTASK

                    SLEEP 5                                                                                 !----Give some time for Delete to complete

                    COPY _methodpaths$ + "STANDBY-AB.M" , _methpath$ + "STANDBY-AB.M", DONTASK


                    !----        _methpath$ is the current method dir.

                    !----        _methodpaths$ is the default method dir.


  • Hello,

    Did you ever find out the version on the system where it was working in the past?


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