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Alternative sources for isotopes

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maecker

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Posts: 23

Joined: Thu Oct 31, 2013 7:58 pm

Post Fri Nov 01, 2013 6:06 pm

Alternative sources for isotopes

Attached is a list of places other than DVS Sciences from which the HIMC has sourced metal salts.

Please note: the Sigma-Aldrich salts are basically the same as the ones you order in the respective kit from DVS Sciences. They are high-purity (99.9+%). It's just that it may be more convenient to order 5-10 grams of the chloride hydrate salt so that your organization will never run out of it.

However: the isotopes listed from Trace Sciences are "USE AT YOUR OWN RISK". The primary reason that DVS does NOT sell them in their kits is that they cannot be sourced at very high purity (98+%). Many of them are typically around 90% pure, with the remaining contaminants being M-1, M+1, and M+2 isotopes of the same metal, as well as other lanthanides (particularly Lanthanum).

I can guarantee that you will minimally have "M+1" spillover questions/issues with the Trace isotopes listed, depending on your signal strength at "M". In some cases, this may be lost in the background or otherwise be negligible to your analysis. In other cases, this could force you to redesign your panel entirely. Therefore, if you *are* going to use them, consider using them for dump channels, and/or strict lineage markers where you use markers for other lineages on the neighboring panel positions.

(This post was originally from Mike Leipold to the HIMC CyTOF Forum in Basecamp, and has been reposted here by Holden Maecker)
Attachments
Non-DVS metal sourcing.xlsx
(41.76 KiB) Downloaded 466 times
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robs

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Posts: 40

Joined: Mon Dec 02, 2013 3:42 pm

Location: University of Connecticut

Post Thu Jan 23, 2014 4:14 pm

Re: Alternative sources for isotopes

Hi All,
Have people found any more sources of Lanthanide Chlorides?
We are attempting the barcoding protocol, but DVS won't be releasing the barcoding kits with metals for a few more months.
We can get the mDOTA chelator from Macrocylcics but don't have another source of metals- DVS is not selling metals separately from the antibody conjugation kits.
Trace will not convert their oxides to chlorides for you, I assume DVS does this in house, and I can only find one metal (144 Nd) currently available from them in highly purified chloride form.
I got a quote from the National Isotope Development Center and the oxides were cheap, under $100 for 10mg, but the service for converting them to chlroides was $1,500 and would take a month
I also inquired at Cambridge Isotope Labs and these guys but didn't hear anything back yet.
I believe the reaction to covert them is pretty straight forward, you add ammonium chloride and heat, but we would prefer to leave that to the chemists, if possible.
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mleipold

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Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Thu Jan 23, 2014 4:38 pm

Re: Alternative sources for isotopes

Hi Ian,

We bought Gd155, Gd157, Dy161, Dy163, and Yb173 as chloride salts from Trace. They list them as oxides, but I insisted that they quote me for chlorides, and they eventually did. I think the chlorides wind up being more expensive because of the extra transformation steps from the oxides, but most labs aren't set up to do the nasty acid treatments to dissolve oxides (I think you need to boil it in concentrated HCl). However, DVS does do it....or at least did with their first set of lanthanides when I was at Toronto.


Mike
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robs

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Posts: 40

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Location: University of Connecticut

Post Fri Jan 24, 2014 6:27 pm

Re: Alternative sources for isotopes

Thanks Mike, can you give me a ballpark figure for how much the chlorides were from Trace per mg or whatever?
I figured we get about 0.1-0.2mg of metal in the 4 reaction DVS conjugation kits which for us is $400, so any service that is more than $2,000 per mg isn't worth it since we could get the metals from the DVS kits (plus buffers and polymer).
-Rob
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mleipold

Guru

Posts: 2095

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Fri Jan 24, 2014 8:00 pm

Re: Alternative sources for isotopes

Hi Rob,

They quoted us at two amounts:

Average of $650 for 10 mg
Average of $1200 for 100mg


Note: these are NOT as pure as DVS isotopes. Most of the impurity is other isotopes of the same element (particularly M+1). Only a small fraction is from other elements.


Mike
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ChristophS

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Location: Switzerland

Post Tue May 03, 2016 5:16 pm

Re: Alternative sources for isotopes

Hi Mike,
I am following in this thread since it touches on Gd isotopes. I have two questions about them.
First, you mention Gd157 which sticks out as the one gap in the Fluidigm portfolio. Have you ever succesfully used it? And would you know, whether its absence has to do with its Barn size (apperently the largest in the lanthanides)?
Secondly, I have used Gd155 to label mouse CD45 and it works well but just lately I observed that it has quite some cross-talk into Bi209 and a little into Yb171. Has anyone else observed such a thing? I am not entirely sure but it could be that the batch of Gd155 dated from the time when it had first been sold by DVS and soon after not anymore for quite a while before coming back (which I heard had been a purity issue). The attached image should show what I mean.

Looking forward to some enlightenment.

Christoph
Attachments
Gd155 xTalk Bi209 Yb171.jpg
Christoph Schwärzler
Director Cytometry
Flow Cytometry Facility (https://www.cytometry.uzh.ch/en.html)
University Zürich
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mleipold

Guru

Posts: 2095

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Tue May 03, 2016 5:25 pm

Re: Alternative sources for isotopes

Hi Christoph,

Gd155 will have an M+16 oxide spillover into Yb171. Like all the other M+16 oxide spillovers, this can be minimized but not completely eliminated.

Gd157 can be added into the MAXPAR polymers just as easily as any of the other Gd isotopes. Therefore, if you can source Gd157 (as the *chloride*, not oxide or metal....), then you can dissolve it and load it. My understanding for why Fluidigm doesn't sell it is a purity issue: they haven't been able to obtain it at their minimum purity (isotopic and elemental) spec.


Regarding the Bi209 spillover you mention: were you using the 209 channel at all in your experiment?

Similarly, 209-16=193, one of the Ir isotopes. So, as control experiments, you might try repeating your experiment, using the Gd155 antibody and using the *Rh103* intercalator. You might also monitor 207 channel, to see if you would see anything there from the 191 Ir isotope.


Mike
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ChristophS

Contributor

Posts: 21

Joined: Thu May 07, 2015 2:11 pm

Location: Switzerland

Post Wed May 04, 2016 8:31 am

Re: Alternative sources for isotopes

Hi Mike,

thanks for the quick response!
The spillover in Yb171 is indeed consistent with Oxide and in the range of 3%. The Spillover in Bi209 is only linked to the Gd155 and not to Ir or other elements in use.
In the Bi209 channel I used ITCB-EDTA loaded with Bi (from acetate, as mentioned in another thread yesterday where I discribed how to load it into the MaxPar polymer) and it has a distinct higher intensity.
I also checked for potential contribution out of Pb208 but that is not the case. I have not yet had a chance to follow up on this with a recently labeled Gd155 reagent that definitely was done with brand new latest batch Gd155.
For the Gd157 I will ask for a quote from TraceSciences and see whether it is affordable. I would like to know though, if you have used it and checked it for unwanted signals from impurities across the lanthanide range (apart from obvioulsy its other isotopes).

Christoph
Christoph Schwärzler
Director Cytometry
Flow Cytometry Facility (https://www.cytometry.uzh.ch/en.html)
University Zürich
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afs1990

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Post Wed May 04, 2016 4:36 pm

Re: Alternative sources for isotopes

This is the quote I received back in October 2015. We decided to not pursue it.

Gd-157 92%+ Chloride 10 mge $35.00/mge 1-2 weeks $350.00

The price, estimated time and enrichment purity may be different now.
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mleipold

Guru

Posts: 2095

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Wed May 04, 2016 5:18 pm

Re: Alternative sources for isotopes

Hi Christoph,

Your impurities (both isotopic and elemental) are going to vary a bit by lot.

For Gd157 chloride, Lot #68-2 from Trace, the spec sheet said:

155: 0.10
156: 1.90
157: 92.3
158: 5.40
160: 0.3
Dy<500ppm
Er<300ppm
Nd<500ppm
Sm: 800ppm
Tb<700ppm
Yb<400ppm


When I labeled an antibody and used a BD Kappa capture comp bead to run on a CyTOFv1, I got (normalized to Gd157 signal):
156: 0.22
157: 100
158: 0.075
No other signal in the 139-193 range.

Exactly why these numbers don't agree completely, I'm not sure. Some of it has to do with signal intensity at M and therefore the ability to completely measure signal intensity at M+1/M-1. Some of it may have to do with the sensitivity profile of the instrument I measured it on (see the Tricot et al paper).

The bottom line, though, is that there wasn't a gross contamination from non-Gd elements.


Mike
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