Tuesday, September 24, 2024

How many scans/peak do you need for accurate quan in LCMS?

 


This is a couple of years ago but this group makes a compelling argument for 6 scans/peak! 

That's about 1/2 what I'm generally trying to get (10-12) but as I'm looking at a LOT of recent data from different instruments it looks like I'm old fashioned. I might need to put up a poll to hear what the community thinks.


2 comments:

  1. This is interesting... The maccoss modeling as applied to right biased peaks shown in the abstract still support >6 scans, ideally 7-8 min.

    However, I'd suggest each of these approaches ignore signal-to-noise contribution. A really intense peak (100x noise floor) with 6 scans doesn't have significant added error from the noise floor. A low intensity peak is much more impacted. Many new, low ion current measures on flagship instruments are combating the noise floor.

    My takeaway here is that blanket statement DPPP metrics are invalid and should be contextualized to instrument + intensity via metrics like LLOQ instead. On top of that, LLOQ needs to be contextualized to more than MS. It needs to be LC hardware config (microflow and nanoflow are very different as are different columns within class!), gradient length, MS, and ideally sample matrix.

    TL;DR DPPP is a decent proxy but known LLOQ in method config is a much better metric.

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  2. I'm a bit worried about the breathless support for 6 scans -- in my experience that directly hurts LOQs and LODs. The authors of the paper didn't appear to explain how they derived their LOQ or determined their linear range so it's hard to make comparisons.

    For my own work, I've determined that 8 is the bare minimal (but I'd rather have 12).

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