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cyanate detection on Qtof 6550 iFunnel

joonseok

Hi!

 

I have been trying hard to detect a small molecule called cyanate (m/z 41.9985) in negative mode using QTOF 6550 iFunnel. We are using a hypercarb column using sodium acetate (20 mM, pH 7) in water for Buffer A and acetonitrile for Buffer B, with a general gradient (95%A to 100%B over ~30 min). After several attempts, we found only "zero abundance" upon EIC for the target mass even with an appropriate range setting on method (m/z 25-3200). Is there anyone who can offer us a good suggestion for the detection? I am also attaching tune report file for detailed settings that w have been using. 

We will really appreciate for any inputs and thank you!

 

Joonseok

  • 0 in reply to jamepyke

    OMG, thank you so much for the great advice, James! I don't even know if there is such an option available. We are using an earlier version software and I will try it! Thank you again!

     

    Joonseok

  • 0

    Hi Joonseok,

     

    A small molecule like cyanate is likely to benefit from a tune that enhances transmission of low m/z ions. Depending on which version of MassHunter Acquisition software you have installed, there are different options to try to optimize the tune for transmission of small ions. In the most recent version, you can select an option to optimize the transmission for 50-250 m/z ions that are fragile or stable... I would try one of these tunes. If you have an earlier version of MassHunter Acquisition software then you could follow the "Manually calibrate the Q-TOF LC/MS for ultra low m/z range" process. The manual process can be found in the help section accessed from MassHunter Acquisition software (from the Help 'Contents' tab navigate to 'Data Acquisition' --> 'TOF/Q-TOF Calibration and Tuning' --> 'Manually calibrate the Q-TOF LC/MS for ultra low m/z range').

     

    Have you tried one of these options?

     

    Kind Regards,

     

    James

  • 0 in reply to jamepyke

    Hi James, I have tried to follow your advice but found an error message below. The Help Contents suggested some critical values for detection of low molecular weight molecules and I tried to change those values as recommended but the system didn't let me. For example, High Pressure Funnel is suggested 120V but the system showed the error message below with a full valid range. In fact, 120V is indeed within the range but I just don't understand why the system doesn't recognize the seemingly appropriate value. Such errors happened in other panels upon attempts to change values. What am I doing wrong?

     

    Thank you!

  • 0

    Hi Joonseok,

    your molecule have a m/z 41.9985, are you sure you can detect molecules with a m/z below 50?

    Even in the "Manually calibrate the Q-TOF LC/MS for ultra low m/z range" suggested by jamepyke the lowest mass is 50!!!

  • 0 in reply to fcozzi

    Oh, the minimum value is 25 on the system and I have seen papers where the cyanate molecule was successfully detected using a similar Agilent Qtof machine (6520 ESI, please see the figure below). I have contacted the author of the paper that I am attaching here and he worries that our AJS could have fragmented the target. By the way, how do you think if I can adjust the value as recommended in the manual tune for small molecule detection?  

     

    Thank you!

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