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Iodine Contamination

PostPosted: Wed Feb 26, 2020 6:20 pm
by msultana
Hi folks!

I am new to CyTOF and I have been experiencing Iodine contamination in my samples which sometime prevent me from running them through the CyTOF machine!!

I have been using Maxpar PBS (From Fluidigm), Maxpar Cell Staining buffer (From Fluidigm), Maxpar Water (From Fluidigm), MACS buffer, Myelin Removal Beads II (from Miltenyi Biotec), Ficoll (From Sigma Aldrich), And the Antibodies are all from Fluidigm

I mash the tumor tissues against the strainer suing the plastic part of the syringe

I do the tumor removal and dissociation on my bench but the myelin removal under the hood

I would appreciate your suggestions and insights regarding this issue!

Re: Iodine Contamination

PostPosted: Thu Feb 27, 2020 4:23 am
by nameerabaig
Hello,

Do you observe Iodine when you run plain water through the instrument? Have you tried running each of your reagents through.

Re: Iodine Contamination

PostPosted: Thu Feb 27, 2020 4:41 am
by ErinSimonds
Ficoll contains sodium metrizoate, which has 3 iodines per molecule. You could try increasing the number of wash steps when you perform your Ficoll preps. Alternatively, you could use non-Ficoll alternatives like Percoll, EasySep Direct PBMC or RosetteSep. Hope that helps.

Re: Iodine Contamination

PostPosted: Thu Feb 27, 2020 6:21 am
by vrozot
Hi,

How are your instruments for dissection decontaminated? There are few standard surgical products used to decontaminate scalpels etc that contain Iodin.

Best,

V

Re: Iodine Contamination

PostPosted: Thu Feb 27, 2020 8:33 am
by jimbomahoney
nameerabaig wrote:Do you observe Iodine when you run plain water through the instrument? Have you tried running each of your reagents through.


I agree, and if so, how many dual counts?

Our instrument has shown low levels of iodine since it was installed - it never goes away.

However, it's such a low amount (typically 15 - 20k dual counts in solution mode) that it's not an issue.

Re: Iodine Contamination

PostPosted: Thu Feb 27, 2020 6:01 pm
by mleipold
ErinSimonds wrote:Ficoll contains sodium metrizoate, which has 3 iodines per molecule. You could try increasing the number of wash steps when you perform your Ficoll preps. Alternatively, you could use non-Ficoll alternatives like Percoll, EasySep Direct PBMC or RosetteSep. Hope that helps.


According to this link ( https://www.stemcell.com/rosettesep-dm- ... edium.html ), it looks like RosetteSep uses Iodixanol (https://en.wikipedia.org/wiki/Iodixanol ; same as Optiprep)


At least as far as I can tell from a 20min internet search, Percoll doesn't contain any iodine-containing chemicals; probably because it works by a different method (colloidal silica particles rather than polysaccharides)

Re: Iodine Contamination

PostPosted: Mon Mar 02, 2020 2:51 pm
by msultana
nameerabaig wrote:Hello,

Do you observe Iodine when you run plain water through the instrument? Have you tried running each of your reagents through.



We wash the samples with EQ beads diluted in Maxpar Cell Acquisition Solution (1:9 dilution)

And haven't thought about running each individual reagent through the machine!

Re: Iodine Contamination

PostPosted: Mon Mar 02, 2020 2:52 pm
by msultana
vrozot wrote:Hi,

How are your instruments for dissection decontaminated? There are few standard surgical products used to decontaminate scalpels etc that contain Iodin.

Best,

V



I place them in 70% ethanol overnight

Re: Iodine Contamination

PostPosted: Mon Mar 02, 2020 2:54 pm
by rgrenfell
Hi

We've seen low Iodine signal in our EQ beads bottle over time. No idea where it comes from though.
Fresh bottles don’t show it, but after a month or so we can see it
Richard

Re: Iodine Contamination

PostPosted: Tue Mar 03, 2020 10:55 pm
by AMitch
Is there any elemental iodine stored anywhere near the beads? We had a similar issue with tuning solution stocks which we stored in a corrosives cabinet. The contamination was tracked down to a bottle of iodine on another shelf in the cabinet which must have had some surface contamination. We think it was sublimating and actually passing through the plastic of the tuning solution bottle.