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Rising Ce140 signal and quite a few other channels

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rgrenfell

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Posts: 26

Joined: Thu Aug 27, 2015 12:31 pm

Post Mon Aug 02, 2021 2:09 pm

Rising Ce140 signal and quite a few other channels

Hi everyone, hope you are all staying safe

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
Attachments
fcs files by time.pdf
(1.39 MiB) Downloaded 73 times
20210716_eae_treat.png
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roexx078

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Joined: Thu Feb 08, 2018 6:21 pm

Location: Nashville, TN, USA

Post Mon Aug 02, 2021 2:25 pm

Re: Rising Ce140 signal and quite a few other channels

Hi Richard

What kind of cells are these? Users at our institution have observed 140Ce signal in samples from lung cancer patients, but I believe only in the tumor. Turns out cerium is the primary metal in lighter flints, so it can show up in smokers.
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rgrenfell

Contributor

Posts: 26

Joined: Thu Aug 27, 2015 12:31 pm

Post Mon Aug 02, 2021 2:41 pm

Re: Rising Ce140 signal and quite a few other channels

Hi,
Thanks, yes,we'd seen some notes about Ce showing up in smokers.
These are mouse samples, so unless the mice are sneaking off behind their wheel for a quick smoke, its unlikely to be that!
Richard
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mleipold

Guru

Posts: 3677

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Tue Aug 03, 2021 12:43 pm

Re: Rising Ce140 signal and quite a few other channels

Hi Richard,

It might have been one of the reagents like PFA:
viewtopic.php?f=7&t=146

You say that it didn't affect every channel; can you tell whether the contamination tracks with nature abundance of various elements? For example, let's say it affected Ce 140/142, but didn't affect Pr141, did affect 142-154 (Nd and Sm), but didn't affect 151 and 153 (Eu).

Do you know if the users did anything else to their cells during the experiment, like bead selection?


Mike
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EricHaas

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Joined: Tue Jun 30, 2020 7:43 pm

Post Tue Aug 03, 2021 7:39 pm

Re: Rising Ce140 signal and quite a few other channels

Hi Richard,

I would echo Mike's concerns about possible magnetic bead separation causing the contamination.

Another possibility is the environment that the samples are being processed. I've seen a set of users from a lab have strange metal contaminations in their samples and while not being able to 100% attribute the source, we found that after they cleaned their sample prep space, the contamination was significantly reduced. Sometimes old/dirty equipment can degrade and cause strange contaminations such as the one you're seeing.

Best,
Eric Haas
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mleipold

Guru

Posts: 3677

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Mon Jun 20, 2022 6:30 pm

Re: Rising Ce140 signal and quite a few other channels

Reopening this thread from almost a year ago:

I saw this paper today that looked at CeO2 nanoparticles in tissue:

"LA-ICP-MS and Immunohistochemical Staining with Lanthanide-Labeled Antibodies to Study the Uptake of CeO2 Nanoparticles by Macrophages in Tissue Sections"
https://doi.org/10.1021/acs.chemrestox.1c00433

- they essentially did Hyperion/IMC, but with their own laser ablation ICP-MS (which is why I'm posting it here rather than Literature). They did use MAXPAR kits to label a few antibodies.

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