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What would your lab be willing to pay to obtain a reasonable (~gram) quantity of a single crystal standard material?

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$25
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Author Topic: Standards Which Should Be Developed For EPMA  (Read 34549 times)

Marc Schrier

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Re: Standards Which Should Be Developed For EPMA
« Reply #15 on: April 22, 2015, 07:24:20 pm »
In looking over what starting materials I have here, I don't have any good cesium starting materials.  Before I purchase some, I figured I'd bounce it off the group in case someone has some to share (or maybe access to a reuse facility).  To start, the materials do not need to be particularly pure, and only once everything is working well (prepare crystals (PXRD), it's water insoluble, polishes nicely, holds up to the beam, looks homogeneous...), then I can pick up purer starting materials.  To prepare the flux(es), any of the following would work as a cesium source: Cs, Cs2O, CsOH, CsOH•H2O, Cs2CO3, CsHCO3, CsOAc (CH3COOCs, cesium acetate), HCOOCs (cesium formate), Cs3PO4, Cs2HPO4, or CsH2PO4.  If you have any you can share, let me know, otherwise I'll try to place an order for some starting materials soon.  I'm not sure if CsZrOPO4 will work, but at least Cs2Zr(PO4)2 and CsZr2(PO4)3 have been prepared.  There are also some Cs/Ti/P/O's.  I probably ought to do some literature searches too and see what I can dig up!

Brian Joy

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Re: Standards Which Should Be Developed For EPMA
« Reply #16 on: April 23, 2015, 10:00:44 am »
In looking over what starting materials I have here, I don't have any good cesium starting materials.  Before I purchase some, I figured I'd bounce it off the group in case someone has some to share (or maybe access to a reuse facility).  To start, the materials do not need to be particularly pure, and only once everything is working well (prepare crystals (PXRD), it's water insoluble, polishes nicely, holds up to the beam, looks homogeneous...), then I can pick up purer starting materials.  To prepare the flux(es), any of the following would work as a cesium source: Cs, Cs2O, CsOH, CsOH•H2O, Cs2CO3, CsHCO3, CsOAc (CH3COOCs, cesium acetate), HCOOCs (cesium formate), Cs3PO4, Cs2HPO4, or CsH2PO4.  If you have any you can share, let me know, otherwise I'll try to place an order for some starting materials soon.  I'm not sure if CsZrOPO4 will work, but at least Cs2Zr(PO4)2 and CsZr2(PO4)3 have been prepared.  There are also some Cs/Ti/P/O's.  I probably ought to do some literature searches too and see what I can dig up!

Hi Marc,

I have 20-25 g Cs2CO3 with stated purity = 99.5 wt%.  Would this be enough for you to get started?  If so, I'd be glad to send it.

Brian
Brian Joy
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Re: Standards Which Should Be Developed For EPMA
« Reply #17 on: April 23, 2015, 10:05:50 am »
In looking over what starting materials I have here, I don't have any good cesium starting materials.  Before I purchase some, I figured I'd bounce it off the group in case someone has some to share (or maybe access to a reuse facility).  To start, the materials do not need to be particularly pure, and only once everything is working well (prepare crystals (PXRD), it's water insoluble, polishes nicely, holds up to the beam, looks homogeneous...), then I can pick up purer starting materials.  To prepare the flux(es), any of the following would work as a cesium source: Cs, Cs2O, CsOH, CsOH•H2O, Cs2CO3, CsHCO3, CsOAc (CH3COOCs, cesium acetate), HCOOCs (cesium formate), Cs3PO4, Cs2HPO4, or CsH2PO4.  If you have any you can share, let me know, otherwise I'll try to place an order for some starting materials soon.  I'm not sure if CsZrOPO4 will work, but at least Cs2Zr(PO4)2 and CsZr2(PO4)3 have been prepared.  There are also some Cs/Ti/P/O's.  I probably ought to do some literature searches too and see what I can dig up!

Hi Marc,
How much Cs starting material would you need to make a few test runs?   How much would that cost?

I haven't received any RbTiOPO4 from the guy at Coherent yet.  I'll ping him Monday.
john
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Marc Schrier

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Re: Standards Which Should Be Developed For EPMA
« Reply #18 on: April 27, 2015, 11:42:39 am »
Brian,
    That would be great if you could send it down!  Twenty grams Cs2CO3 should be enough to get me started; I have the other chemicals.  My address is Marc Schrier, Calchemist, 871 Industrial Rd. Suite K, San Carlos, CA 94070, USA.

John,
    For the first phase I figured I'd get some cheap Cs source to figure out what I can make, and if it stands up.  The cheapest Cs source I came across was Cs2CO3, 99%, and it was just $0.50/g Cs, so ~$100 for 250 grams.  Brian's Cs2CO3 should get me going, and if it goes well, then I'll be more focussed on purity for the next purchase, and we can discuss those requirements when we get to that stage.

In other news I contacted Tom Chatham with Chatham Gems to see if they could offer any assistance, but all of their synthetic gems are doped.

-Marc

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Re: Standards Which Should Be Developed For EPMA
« Reply #19 on: April 27, 2015, 04:53:13 pm »
I got some RbTiOPO4 material from Coherent.  I'm having Julie save a piece for us to analyze for traces and the rest I'll send to Mark Schrier for distribution.  I believe he will charge around $100/gram for this material, with most of the proceeds going towards buying raw material for our next community standard project. 

I'm thinking CsZrOPO4...
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Re: Standards Which Should Be Developed For EPMA
« Reply #20 on: June 11, 2015, 03:05:44 pm »
I finally got around to measuring some trace elements in the RbTiOPO4 material. I measured K, Cs, Na, Ca and Mg using 20 keV, 100 nA counting for 400 seconds on-peak and 400 seconds off-peak:

Un    7 RbTiOPO4
TakeOff = 40.0  KiloVolt = 20.0  Beam Current = 100.  Beam Size =    5
(Magnification (analytical) =  20000),        Beam Mode = Analog  Spot
(Magnification (default) =     1000, Magnification (imaging) =   1000)
Image Shift (X,Y):                                          .00,   .00
Number of Data Lines:   7             Number of 'Good' Data Lines:   7
First/Last Date-Time: 06/11/2015 09:37:16 AM to 06/11/2015 01:14:15 PM
WARNING- Using Exponential Off-Peak correction for cs la
WARNING- Using Exponential Off-Peak correction for na ka

Average Total Oxygen:         .000     Average Total Weight%:  100.015
Average Calculated Oxygen:    .000     Average Atomic Number:   21.781
Average Excess Oxygen:        .000     Average Atomic Weight:   30.549
Average ZAF Iteration:        2.00     Average Quant Iterate:     2.00


Un    7 RbTiOPO4, Results in Elemental Weight Percents
 
ELEM:        K      Cs      Na      Ca      Mg      Rb      Ti       P       O
TYPE:     ANAL    ANAL    ANAL    ANAL    ANAL    SPEC    SPEC    SPEC    SPEC
BGDS:      LIN     EXP     EXP     LIN     LIN
TIME:   400.00  400.00  400.00  400.00  400.00     ---     ---     ---     ---
BEAM:   100.94  100.94  100.94  100.94  100.94     ---     ---     ---     ---

ELEM:        K      Cs      Na      Ca      Mg      Rb      Ti       P       O   SUM 
   360    .015    .013   -.014    .000   -.001  34.979  19.604  12.676  32.741 100.014
   361    .016    .012   -.016    .000   -.001  34.979  19.604  12.676  32.741 100.012
   362    .016    .015   -.012    .000    .000  34.979  19.604  12.676  32.741 100.019
   363    .015    .013   -.017    .000   -.002  34.979  19.604  12.676  32.741 100.010
   364    .016    .015   -.010    .000    .000  34.979  19.604  12.676  32.741 100.021
   365    .015    .013   -.012    .000    .000  34.979  19.604  12.676  32.741 100.017
   366    .016    .012   -.013    .000   -.001  34.979  19.604  12.676  32.741 100.014

AVER:     .016    .014   -.013    .000   -.001  34.979  19.604  12.676  32.741 100.015
SDEV:     .000    .001    .003    .000    .001    .000    .000    .000    .000    .004
SERR:     .000    .000    .001    .000    .000    .000    .000    .000    .000
%RSD:     2.86    9.44  -18.91  273.41  -74.31     .00     .00     .00     .00
STDS:      374    1125     336     358     358     ---     ---     ---     ---

STKF:    .1102   .2652   .0583   .1676   .0644     ---     ---     ---     ---
STCT:   8027.8 14411.6   630.3  6846.5  3948.1     ---     ---     ---     ---

UNKF:    .0001   .0001   .0000   .0000   .0000     ---     ---     ---     ---
UNCT:      9.9     6.3     -.5      .1     -.2     ---     ---     ---     ---
UNBG:     44.7   162.4     7.8    37.9    23.0     ---     ---     ---     ---

ZCOR:   1.1549  1.1603  2.6938  1.0538  1.8504     ---     ---     ---     ---
KRAW:    .0012   .0004  -.0009   .0000  -.0001     ---     ---     ---     ---
PKBG:     1.22    1.04     .93    1.00     .99     ---     ---     ---     ---

Detection limit at 99 % Confidence in Elemental Weight Percent (Single Line):

ELEM:        K      Cs      Na      Ca      Mg
   360    .001    .002    .006    .001    .001
   361    .001    .002    .006    .001    .001
   362    .001    .002    .006    .001    .001
   363    .001    .002    .006    .001    .001
   364    .001    .002    .006    .001    .001
   365    .001    .002    .006    .001    .001
   366    .001    .002    .006    .001    .001

AVER:     .001    .002    .006    .001    .001
SDEV:     .000    .000    .000    .000    .000
SERR:     .000    .000    .000    .000    .000

Detection Limit (t-test) in Elemental Weight Percent (Average of Sample):

ELEM:        K      Cs      Na      Ca      Mg
  60ci    .000    .000    .001    .000    .000
  80ci    .000    .001    .001    .000    .000
  90ci    .000    .001    .002    .000    .000
  95ci    .000    .001    .002    .001    .000
  99ci    .000    .002    .004    .001    .001


The only problematic element was Na due to a very congested background as seen here:



I'll need more work to improve the Na background measurement. But in the meantime this looks like excellent material with less than 200 PPM of K and Cs and no Ca or Mg.
john
« Last Edit: August 09, 2015, 09:04:47 am by Probeman »
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Re: Standards Which Should Be Developed For EPMA
« Reply #21 on: June 11, 2015, 04:40:47 pm »
I'll need more work to improve the Na background measurement. But in the meantime this looks like excellent material with less than 200 PPM of K and Cs and no Ca or Mg.
john

Nice!  Thanks for your work on this.  Is the material available from Marc at this point?
Brian Joy
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Marc Schrier

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Re: Standards Which Should Be Developed For EPMA
« Reply #22 on: June 12, 2015, 03:28:03 pm »
Hi everyone,
    Yes, I have the material, and it's ready for distribution at $100 for a 1 g sample.  For more details see http://www.calchemist.com/standards.htm
I'm working on CsZrOPO4, CsTiOPO4, and CsTiOAsO4, and Ca5(PO4)3Cl, so those are the next things to hopefully see!

-Marc

Sandrin Feig

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Re: Standards Which Should Be Developed For EPMA
« Reply #23 on: June 21, 2015, 11:08:28 pm »
G'day

Very interesting and important topic!

I guess in an ideal world, every lab would use the same standards. That would make the output from different labs better comparable. The standards would be large homogeneous grains with high concentrations of the element of interest and of course beam stable.

At the moment, everybody has access to the Smithsonian's, which are available free of charge(?). The problem that I see with these standards is, that most standards are "small" grains. Some are not homogeneous or have inclusions and they are all natural, not synthetic. Larger grains are available to purchase at places like Astimex, P&H, ...

I like the idea of synthesizing standards.  It is a good feeling to know the composition of the standard that you are using for calibration to measure an unknown. We have quite a few standards where I am not sure how well we actually know their composition....

Ok, back to the ideal world... (@Marc, I will try to convince John) I am not sure, if we need 1kg of material. First of all, most labs are basically broke, because every University wants to do good research, but haven't figured out yet that they need good equipment for that as well (therefore, not every lab will buy all available standards). Second, a lot of labs don't analyses the whole periodic table, but only what the University is "specialized" in. Third, ...

Back to the actual topic, here in Hobart, we do analyse the whole periodic table except for Cs and Rb.  ;)
I guess a standard that we could use is something with Fluorine (ideally large, homogeneous, beam stable, ...). We used to use a Topaz, but we have to replace it and haven't really found a good standard yet. You could use an Apatite or Mica's but they are not beam stable at all. So, to cut a long story short, we are very interested in a Fluorine standard.

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Re: Standards Which Should Be Developed For EPMA
« Reply #24 on: June 22, 2015, 09:10:41 am »
I guess in an ideal world, every lab would use the same standards. That would make the output from different labs better comparable. The standards would be large homogeneous grains with high concentrations of the element of interest and of course beam stable.

Yes, exactly. If we make enough of a standard material, and every lab can obtain that ideal standard for $100 a gram, then maybe every lab in the world *can* use the same standard, at least in these particular places on the periodic table, e.g., Rb.

At the moment, everybody has access to the Smithsonian's, which are available free of charge(?). The problem that I see with these standards is, that most standards are "small" grains. Some are not homogeneous or have inclusions and they are all natural, not synthetic. Larger grains are available to purchase at places like Astimex, P&H, ...

Yes, free fly specks!   Our proposal is to instead create enough of a desired synthetic material that is homogeneous, stable and free from inclusions and available for a nominal amount- $100 won't break the bank for anyone!  The money Marc will make on these sales will go towards synthesizing the next "crowd sourced" standard.

Ok, back to the ideal world... (@Marc, I will try to convince John) I am not sure, if we need 1kg of material. First of all, most labs are basically broke, because every University wants to do good research, but haven't figured out yet that they need good equipment for that as well (therefore, not every lab will buy all available standards). Second, a lot of labs don't analyses the whole periodic table, but only what the University is "specialized" in. Third, ...

1 kg sounds like a lot but it is an upper limit is the point. It depends on the amount we want to distribute and how may labs are there. Here's our thinking: if we have a few hundred grams of material at least, we we'll be able to offer *everyone* 1 gram splits of the material so you won't have to do with a few fly specs anymore!  1 gm of material should last any lab forever!  And how many labs are there?  Well let's assume a few hundred EPMA labs, so that's a few hundred grams already.

But what about SEM labs?  Shouldn't SEM labs also have standards?

http://probesoftware.com/smf/index.php?topic=302.msg1530#msg1530

Adding in SEM labs means we would need 500 or more grams to supply every lab in the world...

Yes, we are starting with Rb and Cs because we already know they are difficult to find good standards for.  Let get more suggestions- this is a crowd sourced effort!

I should also mention, these are not intended to be secondary standards that are similar to your unknown matrix. These are intended to be primary standards, which for statistical purposes (see your quant expressions) need to provide the highest x-ray intensity for a given concentration. Usually that means a major amount of the element of interest regardless of matrix.  The ideal standard for this?  Yes, a pure metal- 99.999% pure of course!

But of course that doesn't work for certain elements, such as Rb and Cs!  Hence our synthesis and distribution efforts...

Back to the actual topic, here in Hobart, we do analyse the whole periodic table except for Cs and Rb.  ;)
I guess a standard that we could use is something with Fluorine (ideally large, homogeneous, beam stable, ...). We used to use a Topaz, but we have to replace it and haven't really found a good standard yet. You could use an Apatite or Mica's but they are not beam stable at all. So, to cut a long story short, we are very interested in a Fluorine standard.

I have to wonder if some labs have avoided Rb and Cs simply because they didn't have decent primary standards...?   ???

But, no worries, maybe no one you know is interested in Rb and Cs.  We do want to hear what your lab needs.  You say, you are interested in fluorine, and that you "used to have" a topaz standard... what happened to it?  Did it wander off?  Disappear during polishing?

I agree that the apatites and phlogopite are beam sensitive.   Tell us, was the topaz beam stable?  Was it natural or synthetic?  Did it have any OH? 

Marc has said that topaz would be easy to grow, but what about the OH molecule?
« Last Edit: June 22, 2015, 10:25:12 am by John Donovan »
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Re: Standards Which Should Be Developed For EPMA
« Reply #25 on: June 25, 2015, 09:21:06 am »
One of my users suggested synthetic olivine-group (X2SiO4, X = Mg, Cr, Mn, Fe, Co, Ni) minerals as potential synthetic standards, especially for transition metals like Co and Ni for which there don't seem to be a lot of options.

I believe some of these may already be in production - our lab inherited a synthetic forsterite which I use fairly often, and I've heard of synthetic fayalite, tephrite and Co-olivine floating around (possibly ORNL products?), but I don't know of any consistent source for them.

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Re: Standards Which Should Be Developed For EPMA
« Reply #26 on: June 26, 2015, 06:32:46 pm »
One of my users suggested synthetic olivine-group (X2SiO4, X = Mg, Cr, Mn, Fe, Co, Ni) minerals as potential synthetic standards, especially for transition metals like Co and Ni for which there don't seem to be a lot of options.

I believe some of these may already be in production - our lab inherited a synthetic forsterite which I use fairly often, and I've heard of synthetic fayalite, tephrite and Co-olivine floating around (possibly ORNL products?), but I don't know of any consistent source for them.

Hi Owen,
Funny, but I recently contacted Lynn Boatner (Oak Ridge Nat'l Lab) regarding any Fe2SiO4 material he might have left over or at least a recipe for making it for Marc Schrier.  I have some of his original synthetic fayalite and it was wonderful- full end member and no metallic Fe. Unfortunately he has not responded.

So, yes this would be an excellent candidate for synthesis for our crowd sourcing efforts...  any one have any recipes for making synthetic fayalite?

I should also ask what you want the Co, Mn, Ni, etc olivines for...  I have some transition metal olivines from the Purdue crystal lab many moons ago, but the only real use I've found for them is testing matrix corrections and MAN corrections. 

That is to say, for trace element work, you can utilize the pure metal or oxide just as well.
« Last Edit: June 27, 2015, 12:07:03 pm by John Donovan »
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Re: Standards Which Should Be Developed For EPMA
« Reply #27 on: June 29, 2015, 10:26:18 am »
I should also ask what you want the Co, Mn, Ni, etc olivines for...  I have some transition metal olivines from the Purdue crystal lab many moons ago, but the only real use I've found for them is testing matrix corrections and MAN corrections. 

Hi John,

1. Some of the glasses/compounds/synthetic minerals/stuff from our Materials Science folks can have a fair amount of Co, Mn, Ni, etc (1-10 wt% level, more on occasion).

2. A lot of the sulfides we get can have major Ni and Co (again, > or >>1wt% levels).

While the synthetic olivines wouldn't be the best matrix match (especially for the sulfides) they would at least polish well and not degrade as badly over time as the Co and Ni pure metals/sulfides I use now, as well as having better and more reproducible "published" compositions.

As far as recipies go, the only one I've seen is a sol-gel method for growing nanocrystalline fayalite. Obviously we don't want nanocrystalline material, so this may not be the most useful, but the reference is:

 DeAngelis, M.T., Rondinone, A.J., Pawel, M.D., Labotka, T.C. and Anovitz, L.M. (2012) Sol-gel synthesis of nanocrystalline fayalite (Fe2SiO4). American Mineralogist, v. 97, p. 653-656, doi:10.2138/am.2012.3899

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Re: Standards Which Should Be Developed For EPMA
« Reply #28 on: June 29, 2015, 10:51:08 am »
I should also ask what you want the Co, Mn, Ni, etc olivines for...  I have some transition metal olivines from the Purdue crystal lab many moons ago, but the only real use I've found for them is testing matrix corrections and MAN corrections. 
1. Some of the glasses/compounds/synthetic minerals/stuff from our Materials Science folks can have a fair amount of Co, Mn, Ni, etc (1-10 wt% level, more on occasion).
Hi Owen,
Thanks for the feedback.

Please believe me, I'm not trying to discourage the development of synthetic crystal standards, but I am trying to keep us focused on new standards that will have the most positive impact on our analyses. If your silicate samples have 10% Co, Mn, Ni, etc. then you might have a case for us synthesizing some unusual end-members of the olivine family.

But because the Co, Mn, Ni, etc. emission lines are quite energetic, and these materials all have about the same average atomic number, it's not clear to me that having these end-member standards available, will provide an significant improvement.  Now the situation is quite different for measurements of Si Ka in these materials, because the absorption correction is quite large and even worse is the situation for high atomic number silicates when the atomic number correction starts to really kick in and one is using SiO2 as a Si standard!

One of the most useful crystals which I was lucky enough to obtain some perfect natural crystals of was alamoite or PbSiO3. This is the perfect Pb standard for the microprobe. HfSiO4 would also be interesting but there is a nasty absorption edge problem for Si ka, which incidently does make it an excellent material for physics studies...

http://probesoftware.com/smf/index.php?topic=152.msg1637#msg1637

2. A lot of the sulfides we get can have major Ni and Co (again, > or >>1wt% levels).

While the synthetic olivines wouldn't be the best matrix match (especially for the sulfides) they would at least polish well and not degrade as badly over time as the Co and Ni pure metals/sulfides I use now, as well as having better and more reproducible "published" compositions.

Similar for these minor concentrations as above. For now you're better off with polishing your standard mount once a year.  But I think it is a good idea to get to these weird olivine materials at some point.

As far as recipies go, the only one I've seen is a sol-gel method for growing nanocrystalline fayalite. Obviously we don't want nanocrystalline material, so this may not be the most useful, but the reference is:

 DeAngelis, M.T., Rondinone, A.J., Pawel, M.D., Labotka, T.C. and Anovitz, L.M. (2012) Sol-gel synthesis of nanocrystalline fayalite (Fe2SiO4). American Mineralogist, v. 97, p. 653-656, doi:10.2138/am.2012.3899

Marc may find this helpful, thanks!
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Re: Standards Which Should Be Developed For EPMA
« Reply #29 on: June 29, 2015, 05:40:07 pm »
Fair enough - if I'm the only one after these, then let's bump this down the priority list. And if you have some leftovers of the Purdue olivines and want rid of them, I'd be open to negotiation...