UPLC and Calibration

<p><span>Hi,</span></p><p></p><p><span>We currently have yearly calibrations performed by waters technicians. We are writing an interal calibartion procedure to be performed anually also but offset six months to the Waters Calibration.</span></p><p><span>The waters calibration procedure is very specific to a particular configuration of the instrument. For example we have changed the following on our instrument , 425 uL mixing chamber, flow restrictor, 5uL loop, stainless steel needle. My question is do waters engineers change all this back to the standard operating system before performing a calibration or do they adapt the procedure? And if they change the system to the standard how can we say that the system is calibrated when we change it back to the non-standard operating system.</span></p><p></p><p><span>Thanks for your help</span></p>


  • lizh


    I was not sure if anyone would reply to this, but here goes. As Waters cannot easily support all the posible configurations, there has to be a chosen configuration for testing rather than choose an application specific test.

    Calibration is a way to ensure that the system works correctly, within its expected operational specifications. The changes you outlined, are used to ensure that the mixing and th UV noise are suitabe for your application. Therefore, it may be that you could in addition use a sample that you understand well with know characteristics to verify that the system is working.for this specific application. This way you will have established that the system works as expected and as expected for your application.

    Would this be a possibility? I could also check if we have a sample that could be used for this additional check if you wish.

    Best regards,



    Thanks Elizabeth,

    I would appreciate it if you could tell me if there is a suitable compound/method for this, one that you may have already identified.

    AS alot of our work is at the development stage do not have a UPLC method that we would say is robust enough for this.

    Thanks very much for your help,