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Contamination (Ba mostly) Testing

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MattCochran

Participant

Posts: 6

Joined: Fri May 30, 2014 3:34 pm

Post Tue Dec 22, 2015 5:07 pm

Contamination (Ba mostly) Testing

I was searching for posts related to Ba contamination and came across a number of things. I decided to create a new thread as I've seen reference a few times in other threads something that I didn't think was a good idea. Specifically Mike and others have suggested running buffers in the liquid mode to test for contamination sources. While this does make sense as a fairly easy way of testing and verifying the source of the contamination, I didn't think it was recommended by DVS/Fluidigm? I was under the impression that this would cause possible issues with the detector and/or "dirty" the instrument so much it would be difficult to repair.

After reading a bit more it seems that maybe this is a pretty normal practice as long as you understand you'll probably have to take the glassware out and clean the cones more thoroughly than normal. It will not however, destroy anything in the instrument?

Do people that do this usually run the straight buffer or do you dilute it in clean water to minimize the potential for dirtiness?

Are there any other considerations that need to be addressed?

Thanks for all the useful discussion everyone,
Matt
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AdeebR

Grand master

Posts: 169

Joined: Thu Mar 13, 2014 5:58 pm

Location: NYC

Post Tue Dec 22, 2015 7:11 pm

Re: Contamination (Ba mostly) Testing

Hi Matt,

When testing buffers, rather than running them directly on the CyTOF I usually incubate cells in the buffer for ~1hr and then run the cells (using a full background testing template). I feel this provides a better approximation of the situation that will be encountered with an actual samples, and also doesn't dirty up the instrument as much.

Adeeb
Adeeb Rahman
Icahn School of Medicine at Mount Sinai, NYC
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robs

Contributor

Posts: 40

Joined: Mon Dec 02, 2013 3:42 pm

Location: University of Connecticut

Post Tue Dec 22, 2015 11:29 pm

Re: Contamination (Ba mostly) Testing

Hi Matt,
If I had to analyze buffer and wasn't sure what was in it, I always made serial dilutions of the buffer in milliQ water and ran the most dilute sample first. If I didn't see any contamination in the dilute sample I'd move to the next most concentrated. I never ran the buffer straight.
Rob
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MattCochran

Participant

Posts: 6

Joined: Fri May 30, 2014 3:34 pm

Post Wed Dec 23, 2015 2:24 pm

Re: Contamination (Ba mostly) Testing

Both good recommendations thanks. We'll give them a shot.
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anitamkant

Master

Posts: 51

Joined: Mon Nov 18, 2013 6:30 am

Post Wed Dec 23, 2015 6:55 pm

Re: Contamination (Ba mostly) Testing

Hi Matt,
It is always advisable to check the background metal levels from the reagents and buffers used in the experiment.
Your question is: "Will testing them as "Neat" a) dirty the parts and b) cause damage to the detector?"

A: It is always advisable to dilute any unknown (for the level of contamination) buffer before testing it on CyTOF and as Rob suggested start with the highest dilution.

The rule of thumb is that the total dissolved solids of any solution which is introduced into the plasma should not be above 0.1%, and for the safety of the detector, it is better to be under 10 ppb for metals. If one suspects Ba at a ppm level, 1:1,000 dilution is recommended before running.

Also, checking the vendor's certificate of analysis is a must when dealing with new buffers. Selection of high purity ones is recommended. For example, some manufacturers will specify Heavy Metals (like Pb) < 5 ppm. Thus, one would want to dilute 500 times to have less than 10 ppb of metals, before running on CyTOF.

Some specifications would show actual detailed content of the most common metal contaminations. One would need to assess the highest level and dilute accordingly.

1000 times is a reasonable general estimate.
Please do not hesitate to contact your local Field Application Scientist and Technical Support Team at Fluidigm for any further questions.

Regards,
Fluidigm Team

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