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Cleaning the CyTOF

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Ofir

Master

Posts: 75

Joined: Thu Nov 07, 2013 12:46 pm

Location: US, CA

Post Fri Nov 22, 2013 5:33 am

Cleaning the CyTOF

Dear CyTOFers,
We have been given various advise on the required frequency of cleaning various parts of our CyTOF 1 machine. These ranged from every 10 samples to once a week (on a very busy machine).

How often do you clean the from end (torch assembly and injector), and how often the skimmer-reducer assembly? Do you use a special recipe or the DVS standard solutions?

Thanks!
Ofir
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mleipold

Guru

Posts: 5796

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Mon Nov 25, 2013 11:31 pm

Re: Cleaning the CyTOF

Hi Ofir,

Here at the Stanford HIMC (two CyTOFv1 machines), we clean the spray chamber, tune the Current and Makeup Gas optima, and check the Tb gain/Detector Voltage daily. We also run Wash solution (from DVS) during warm-up to remove residual metal buildup, and then at the end of the day, run Wash again. If Pd, Cd, or any other +2 metal has been used, we also run 3% nitric (diluted from Optima grade, in MilliQ water): those metals seem to be better removed with nitric rather than the hydrofluoric acid in the Wash solution.

During running, it doesn't hurt to run Wash solution occasionally during long days of acquisition. Particularly if you have dirty samples, or stickier samples like whole-blood; you might run a minute of Wash every 3-4 samples, and then run water until the free metal is gone.

I clean the cones (2 metal parts, large and small) weekly. This also includes inspecting the copper Rf coil for damage (and a wipe with a Kimwipe with methanol), and end of the torch body for copper deposits. If there are copper deposits, a soaking in 3% or concentrated nitric acid will usually remove them. I also check the alignment (how coaxial the torch body is aligned within the Rf coil). I also check the XY alignment weekly.

Every two weeks, I remove the torch assembly and at least inspect the torch body and injector. Most of the time, I'll remove the torch body and injector and scrub them clean as well. I also scrub the igniter pin and wipe it with a Kimwipe with methanol. Both this and the weekly cleaning are also a change to inspect O-rings for cracks, stiffness, and tackiness (and replace them if necessary).


Oil needs to be changed every few months. The main one that will need to be changed is the interface pump (the bottom one). This is highly machine- and use-dependent: HIMC CyTOF #1 needs to have that oil changed every 3-4 months, whereas HIMC CyTOF #2 is more like every 6 months.


Mike
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mmeyrand

Participant

Posts: 6

Joined: Tue Nov 26, 2013 8:20 am

Location: Marseille, FRANCE

Post Tue Nov 26, 2013 10:02 am

Re: Cleaning the CyTOF

Hi Ofir,
Just a comment about cleanning.
before and between samples, i usually flush the sample loop by injecting (loading position) first 3 syringes of water and 3 syringes of washing solution. I let the 3rd syringe containing washing solution going for 2 or 3min (injecting position) to make sure to clean the nebulizer capillary. It takes about a 45sec between the valve and the nebulizer (depending of your flow rate).
During the washing injection, make sure to move several time the valve, I notice that cells/beads can stay in the valve and could be released in the next sample if the valve is durty.
At the end of my cleaning procedure, between samples, I flush again the loop with 3 syringes of water and let water going for 2min to make sure the system is full of water.
To prevent damaging your detector (life time), do not let the acquisition ON (MPR RPR or preview) for a long time during cleaning. I usually check for few seconds only. When there is no acquisition the ions beam are not directed to the TOF detector.

Before shutting down the Cytof, I run washing solution in the 3ml syringe for 30min and the I rince with water.

We clean nebulizer every evening, we clean spray chamber after the runs everytime we inject cells samples (but I don't clean if it Torch was [On] for a really quick QC and metal content check since "samples" are in acid already)
We check the torck and cone sampler every week.
A good way to know if the cone sampler and skimmer/reducer are durty is the current value. Usually we need to increase this value from 6/7 to 8/9 and I do think it is a good indicator to know the skimmer needs to be clean. For now, we don't inject thousands of sample, so cleaning once a month sounds enough for us.
We of course check for torch alignment everytime we open the cytof, we check for current every QC. I tune others parameters when I notice a roblem during QC (oxydation, gain to high or to low...)
I hope it helps,
Mickael
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Ofir

Master

Posts: 75

Joined: Thu Nov 07, 2013 12:46 pm

Location: US, CA

Post Tue Dec 03, 2013 11:06 am

Re: Cleaning the CyTOF

So... our coil can get very dirty with what looks like sticky black soot.
The recommended Methanol / sand paper method is very time consuming. It's also hard to thoroughly clean inside the coil twists.
Does anyone have a better and quicker method for cleaning the coil??
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mleipold

Guru

Posts: 5796

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Tue Dec 03, 2013 7:35 pm

Re: Cleaning the CyTOF

Regarding the copper RF coil:

1. There is a distinction between soot (powder that can be removed with a Kimwipe and methanol), and simple oxidation of the copper in the coil.

When a coil is new, it is the regular copper color. Over time, it will turn greyish or at least darker. This color change is to be expected: it's an oxidation of the copper (or, maybe an argon adduct; I don't know the chemistry behind the color change). This color change is harmless, and will not affect the running of the machine. Therefore, it doesn't need to get removed.

Soot, on the other hand, should be wiped away with methanol on a Kimwipe (please use Kimwipes, or some other certified lint-free material). I *think* this soot is copper in origin, but I'm not sure. Regardless, you do want to remove it, or it can contribute to arcing events. But wiping with a methanol-wetted Kimwipe usually is sufficient to clean. Balling it up lightly so it can wedge into the coil turns usually works well enough.

To get between the coil turns, or between the torch body and the coil, you can cut a section of pipe cleaner (craft supply stores have them as well), dip in methanol, and run in the areas needed. You can also use a pipe cleaner for cleaning the injector tip, and the narrow end of the spray chamber near the ball joint (where a lot of scrub brushes have a hard time reaching). I would watch out for lint, and also use the white pipe cleaners (the dyes in colored products are sometimes metal-based).


2. In most cases, a kitchen scrub pad is usually sufficient to scrub the coil and igniter pin to remove oxidation (in the US, they're often green; don't get the kind with embedded detergent). Fine-grade andpaper is usually only required if there is significant damage to the Rf coil after an arcing event. Scrub at the spot lightly until it's smoothed again, then with the green scrubby, then wipe with methanol until no soot comes off onto the Kimwipe or pipe cleaner.


In all cases, cut down the size of the scrubby, sand paper, or pipe cleaner so it's easier to reach into the machine (CyTOFv2 is a little easier in that regard than CyTOFv1).
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Ofir

Master

Posts: 75

Joined: Thu Nov 07, 2013 12:46 pm

Location: US, CA

Post Tue Dec 03, 2013 7:53 pm

Re: Cleaning the CyTOF

Thanks Mike,
I guess what we have is copper oxidation as it does not come off with gentle kimwipe / methanol treatment.
I am a little worried that it would build up over time and change the dimensions and uniformity of the coil.

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