Topic: Practical Training
Podium Presentation in Room 6 on Thursday at 13:15 (Chair: Russ Grant / Grace van der Gugten)
Authors: Dr Russ Grant
Central to determining assay quality and results reporting apriori is the fundamental belief that one is selectively measuring the analyte of choice. The use of transition ratio monitoring, while somewhat known to many users of tandem mass spectrometry, still provides a multitude of discreet challenges in the development, use and interrogation of chromatographic data. This one hour teaching session regarding Transition Ratio monitoring (peak purity analysis) will be delivered in three 20 minute vignettes. The entire session will traverse the journey and demonstrate the utility of transition ratio monitoring from guidance through initial development, assay refinement and validation with key experiments and decision making processes throughout.
The first session will describe current guidance (or lack thereof), requirements for qualifying versus quantifying transitions and use of transition ratio monitoring in early to mid-stage assay development decision making (including favoring selectivity over sensitivity).
The second session will focus heavily on refinement of assay parameters to enable selection of qualifying and quantifying transitions in difficult real world situations. These will include non-linear calibration systems (detector and source saturation), low sensitivity qualifying transitions (summing, dwell time manipulation and scheduled SRM for improved peak selection) and what to do when only one transition is viable (Collision energy off-setting for the same transition).
The third session will focus on pre-validation and assay validation experiments required to define transition ratio performance in clinical use. These experiments will include asymmetric ion ratios, multiple ion ratios to enable results release, reflex to stretched gradients for re-injection release and variance cutoffs for confidence in selectivity. The session closes with the uses of transition ratios as the definitive acceptance criterion for qualitative proteomic fingerprinting.
Take home Pearls.
1. How to select appropriate transitions for use in transition ratio monitoring - including tools to enhance S:N for low intensity transitions.
2. How to improve the precision of Transition ratio's through scheduling and appropriate dwell times.
3. How to design transition ratio tolerances to enhance medical utility and including when to ignore the qualifier transition.
|Expenses||yes||AACC and MSACL|
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