Hi Joanne,
Thanks for the data.....I haven't explored this closely.
A few questions or comments:
1. While I certainly agree that the cell signal you're showing is of *lowER* intensity than the main EQ isotopes, I still wouldn't call Dual ~100 (your CD27) a *low* intensity signal. If there were problems, I would expect it to only kick in closer to Dual ~10-30.
Have you tried gating on you EQ beads, then looking at the 142 and 176 channels, and maybe the 156 (Ce140+16) as well? Those are pretty low-intensity signals that are contained in the EQ beads themselved but, if I recall, *aren't* actually pegged to specific values during Fluidigm normalization (definitely not used in the MATLAB one). If the norm'ing were correct, then you would expect that the 142/176/156 would be a flat line like the other EQ isotopes.
2. Did you have noise reduction on during this acquisition? If so, could there be a baselining issue like previously discussed? (eg,
viewtopic.php?f=4&t=582) Of course, that's mainly an issue if you had streaking in your sample.
Yes, in short, I do believe that the CyTOF community needs all the kind of bead standards that the fluorescent flow community does ("empty" background beads, multi-level or intensity beads perhaps even for Tuning/Calibration, etc). In addition to Fluidigm, I've been talking with some companies like Spherotech and Bangs about this; some are aware that it's a problem and they're talking with Fluidigm and other people about it. Others seemed surprised that CyTOF even existed, and didn't understand the potential market.
The more of us that yell for the standards, hopefully the sooner we'll get them......
Mike