Pretreatment Method parameters in Empower

Dear All,

 

We are having issues with setting Pretreatment Method parameters in Empower 3 with ICF 3.0. When attempting to add the second needle wash, the chromatography shows absolutely no peaks (almost as if it is injection the wash solution instead of sample), and appears as a blank injection. As soon as I removed the wash and only have one time, the chromatography is as expected.

 

Has anybody experienced same?

 

Regards,

Weronika

  • Hello Howard,

     

    Sampler is G1329A.

     

    What use to work was: in Empower 3 FR2 (I don’t know ICF version)

     

     

    With the Empower 3 FR5 and ICF 3.0, the option for adding a second needle wash is hidden under ‘pre-treatment method’… however, it does not work. When attempting to add the second needle wash, the chromatography shows absolutely no peaks (almost as if it is injection the wash solution instead of sample), and appears as a blank injection. As soon as  the wash was removed and only have one time, the chromatography is as expected.

     

     

     

     

    Regards,

    Weronika

    attachments.zip
  • Hi,

    Thank you for prompt reply.

     

    Yes first picture was referring to older version of Empower that was recently upgraded, and now we have Pretreatment Method tab available for Instrument Method Editor:

     

     

    We will try out new solution that you provided.

     

    Thanks again.

     

    Regards,

    Weronika

  • Hello,

     

    I added tags to this post to increase visibility. 

     

    I am not personally familiar with Empower so I personally will not be of much help here. Hopefully some who does have experience using the ICF with Empower can chime in.

  • Hi ,

     

    Is this a pretreatment/injector program that has been used successfully on Agilent data systems? If you could provide the model number of your autosampler and the steps in your working program and the non working program we may be able to at least isolate to a possible ICF/Empower issue or an issue with the injector steps/program being used. 

  • ,

    This appears to be an older version of Empower, as newer versions using the latest ICF tend to have the Agilent style dialogs/GUI. 

     

    But either way, on our LCs if a pretreatment method is specified it overrides all other injection steps. So you cannot simply add something that you want to happen during the normal series of injection steps. You must manually recreate all of the injection steps in the pretreatment. 

     

    For example, if you want to make certain you rinse the needle before and after you draw from the sample you would need to create a program that looks something like this.

     

    Your dialog will look different of course, but those options, or something like them should be present.

  • Hi Howard,

    The analyst created the following pretreatment method:

     

    While it successfully performed the 2x needle wash with the sample injection, after the vial and needle were still in the wash position, and she had to manually shut-down the whole sample manager for the needle/arm to reset. Is there a way to home the sample arm and returning the wash vial?

     

    Regards,

    Kim

  • ,

    I can see several potential issues with attempting to perform a post injection needle wash, especially if you are running a gradient LC method.

     

    With your current program you perform an injection, which places the needle into the seat and the switches the valve to mainpass. Then you immediately switch the valve back to bypass for the wash, stopping the flow of solvent through the loop, needle, and seat. I suspect that will not be enough time to adequately flush your sample out of the sampler and onto your column. You can add a WAIT command and flush the injection path with however much solvent volume you think will be necessary to get your sample into the flow path. But then you must switch the valve back to bypass during the analytical portion of your run to perform the wash. This will cause a baseline disturbance, though if you can do it before the void volume time it might not affect things too much, but you would have to determine that experimentally. 

     

    Now you can perform your wash, but your loop, needle, and seat are no longer part of the flow path, and if you are performing a gradient run they will not have their internal volume flushed with your organic phase (assuming you are doing reverse phase work) unless you again switch the valve back, which will cause another baseline disturbance and flush a slug of your starting condition eluent onto your column. Depending on where you are in your gradient this may not be desirable. 

     

    You could just leave it in bypass until your last peak of interest comes out and then switch the valve back, but then you are mixing your starting condition eluent directly with your end run eluent composition. If you are using buffers that may not be the best thing to do.

     

    I would suggest referring to the sampling sequence information that starts on page 10 of the user manual found here to have a full understanding of how an injection sequence normally works to help in making your injection program. 

     

    As for removing the wash vial I believe you can use the NEEDLE command and tell it to go into the seat. This should return the vial to the tray and lower the needle into the seat. Then you would have to decide if you want to use a VALVE command to switch back to mainpass right away or how you would want to proceed.

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