Hello,
I recently found a tech note by SCIEX on the MRM algorithm (see here: https://www.sciex.com/tech-notes/technology/the-scheduled-mrm–algorithm-pro). In there, the dynamic window extension was mentioned as a very handy tool to improve method robustness. Since we have had issues with RTs shifts out of the user-defined windows, I was very interested in getting the dynamic window extension to work in our system (LC-QTOF/MS, X500R). However, I could not find this functionality in SCIEX OS. Is it still available? If so, how can I access it?
Thank you,
Jimmy
Hi there, Jimmy,
Currently the advanced MRM scheduling features are only available on the QQQ and QTRAP systems. For SCIEX OS software supporting the QQQ systems, the advanced scheduling features that were migrated from Analyst software are:
• Manually editable or software-calculated dwell times
• MRM-triggered MRM (called “Apply sMRM triggering” on SCIEX OS software) with DBS for background subtraction
• Individual RT windows (RT tolerances)
• *** New – Scout triggered MRM algorithm – this is in favor of using the dynamic window extension as it is a better way to handle potential RT drift.
o (See technical note https://sciex.com/tech-notes/technology/scout-triggered-mrm-algorithm–the-evolution-of-the-mrm-workflow)
• *** New – Integrated sMRM summary plots
For the X500R or ZenoTOF 7600 systems that operate using SCIEX OS software, you are able to schedule the acquisition of compounds using scheduled MRMhr but can only specify a window width. You can use different window widths for different compounds, if you are finding some compounds are more susceptible to RT changes than others. And you can set different accumulation times for different compounds if desired to manage cycle time.
I suppose the other thing you could think about is switching to using SWATH DIA on your QTOF system. The specificity might not be quite as high as you use wider Q1 windows, but you will never have to think about retention time again and can analyze unlimited numbers of compounds! 😊
On our SCIEX website, there is a place where users can suggest new software features. (https://sciex.com/support/software-feature-requests)
Hope this helps,
Christie