Rising Ce140 signal and quite a few other channels
The other day we came across something weird that we cannot explain. Would love some advice please.
I normally have a 191 vs 140 plot while acquiring but noticed that pretty much all the cells had picked up,or were picking up, Ce140. Never seen this before.
I had run a small bit of the barcoded sample, saw it was too concentrated (didn't count beforehand - yes, I know I should have) diluted it down with the CAS they had brought to resuspend the pellet, and ran 4, half hour, collections. As I had seen it in a channel that wouldn't affect the data, I wasn't too worried (other than trying to work out where it had come from), but it has impacted a number of channels.
Looking at all the channels vs time, it looks like this has affected somewhere around 13 different channels from 140 up to 162, but not every single channel though, and also affects some channels where there were no markers for this sample.
The effect looks to be quite strong in the lower mass range there, decreasing as you go higher, I wonder if there is a +16 effect from some of the lower ones.
I'm attaching a PDF of Ce140 vs time, with the 5 runs in time order, bracketed by 2 other samples that I happened to run before (11am) and after (3pm) the barcoded sample.
The Ce140 looks to be very much associated with cell, rather than being streaky background. (screenshot of the rainplot attached)
At the time, I didn't think to record an 'All Channels' file or look at the rainplot of TOF to see if there was anything unusual outside of the recorded channels.
I can upload the .fcs file if needed.
We're going to run some of the buffers tomorrow to see if there is anything weird there, but not sure what would effect so many channels at the same time.
I'm stumped.
Any ideas?
Thanks
Richard