Concern about frozen samples

Discussion in 'ATI Aquaristik' started by Randy Holmes-Farley, Feb 6, 2018.

  1. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    Hi ATI,

    I don't quite understand the company response that someone in my forum got when asking about what effect frezzing might have on an ICP sample.

    Can I get someone to expand on that comment and explain why precipitation of calcium carbonate from hypersaline solutions that remain after freezing could not be impacting the results for a variety of ions?

    Do you acidify the samples in the submitted vials to dissolve any solids?

    TIA

    https://www.reef2reef.com/threads/frozen-ati-icp-test-samples.357037/
     
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  2. Centurio

    Centurio Member

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    Following.
     
  3. Cnidoblast

    Cnidoblast Active Member

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  4. Rajil

    Rajil Member

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    Here is the response.[​IMG]
     
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  5. Hitman

    Hitman Active Member Build Thread Contributor

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  6. Want2BS8ed

    Want2BS8ed Active Member R2R Supporter

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    FYI, Triton has repeated the same in the past...

    Following for the eventual answer.

    M
     
  7. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    Yes, they too apparently do not understand the issue, an I know in their case they do not acidify the sample, so will potentially have an issue if calcium carbonate precipitates.
     
  8. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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  9. Want2BS8ed

    Want2BS8ed Active Member R2R Supporter

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    Thanks Randy!
     
  10. monkiboy

    monkiboy Well-Known Member R2R Supporter

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  11. Finhead

    Finhead Active Member

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  12. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

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    Perhaps this freezing can be OK due to the unusual form of calcium carbonate (ikaite) that forms at very low temps (see link below), which appears to redissolve at higher temps (unlike calcite or aragonite). Most of the major ion minerals certainyl will redissolve. My main question is the trace metals that may get into carbonate or oxides.

    That said, since so many folks samples are freezing, I think it would be interesting to see if trace metals that get incorporated into such precipitates will redissolve and give the same values before and after substantial freezing.

    https://www.the-cryosphere.net/8/1469/2014/tc-8-1469-2014.pdf
    "In our study, ikaite precipitated in sea ice at temperatures below – 4 ◦C"
     
  13. ATI North America

    ATI North America Well-Known Member R2R Supporter Gold Sponsor

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    This is out of my league, I will see if I can get some assistance from Germany. I know this was recently asked on Facebook as well and the same response was given.
     
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  14. Cory

    Cory Valuable Member R2R Supporter Article Contributor

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    Imo all of these cheap icp companies need to offer centrifuging and heat pack shipping.

    Organisms and other particles will effect results. And if the sample freezes as Randy said, it creates a hypersaline area that will precipitate various ions wich wont redissolve. Thats a huge concern.

    Even if you charged more for centrifuging a sample, id pay it.
     
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  15. rkpetersen

    rkpetersen Well-Known Member R2R Supporter Partner Member 2018

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    The only way their answer would be correct is if everything completely redissolves upon thawing. Any persistent precipitate at all will invalidate the test. I wonder if they even assess for this when they receive the samples? There is no reporting of 'sample condition', or similar, from any of the ICPOES companies.
     
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  16. Want2BS8ed

    Want2BS8ed Active Member R2R Supporter

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    @ATI North America, any updates from the folks in Germany?

    M
    IMG_0446.GIF
    Shamelessly stolen from @GoVols. Hilarious even if it makes my nose hurt everytime!
     
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  17. ATI North America

    ATI North America Well-Known Member R2R Supporter Gold Sponsor

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    Yes! I followed up with him again last night and had a reply waiting here this AM. These are not my words below:

    "We are selling natural seawater. Therefore access to fresh natural seawater is provided constantly.

    We are storing this water outside in big holding tanks and in winter it could be that the water inside is freezing. When we get a new delivery of natural seawater, we do analyze this water. This water is also analyzed before we sell it. I could not observe any significant change in the composition of this water even if parts of it were frozen in the meantime.

    Of course these results are not representative for what happens with the samples when they got frozen in the vials. Therefore these results are not shown, but we have done the following test for you people (especially for you Randy).

    We have taken two samples from the same source of natural seawater. One was stored at 20°C and the other was frozen at -10°C for 24 hours.
    Samples.jpg

    After the frozen sample was melted at room temperature we did ICP-OES analysis only (therefore KH, NO3 and F is missing). No precipitations were observed.

    20°C http://lab.atiaquaristik.com/share/78986375df453d7e7ef3

    -10°C http://lab.atiaquaristik.com/share/896b2eb7c3d421f08817

    There is no significant difference between the results, all differences are within the normal range of tolerance that the ICP machine has. "
     
  18. Rajil

    Rajil Member

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    Well this escalated quickly! Seriously though I appreciate everything you guys did to verify and confirm. Excellent customer service! And my thanks to Randy for always being an advocate for the community on these type of issues.
     
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  19. Cory

    Cory Valuable Member R2R Supporter Article Contributor

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    -10c isnt cold enough. You need thr sample to get to -36 C according to another thread
     
  20. ATI North America

    ATI North America Well-Known Member R2R Supporter Gold Sponsor

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    Where would a sample be that would get that cold for a long enough period of time to have the sample be that temperature?
     
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