Frozen sample issue

[Randy Holmes-Farley]

I know you may not want to post in another sponsors forum, so we can discuss it here, but here's the background and how you got mentioned as suggesting freezing is not an issue:

https://www.reef2reef.com/threads/concern-about-frozen-samples.357285/

My starting discussion (which also seems to relate to Triton comments):


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/

 

[cthedaytrader]

I have actually always wondered this myself, I don't see how it wouldn't affect it on some level, but since I was never sure, I just haven't sent any samples in when the temperatures are too cold.

While I know it wouldn't give the scientific explanation, I would love to see a simple experiment to see how it does affect the results. Why couldn't they just take a number of samples from the same source water, the more the better, but I would say at least three (3), and then test one set right away, while then freezing another set, thawing and testing them and publish the results. I would say so long as it was an honest study it would show if the freezing of any samples changes the test results at all, at least from a consumers perspective. I am sure there are a number of other variables that could also be tested as well and accounted, but at least there could be a determination on if the results are changed or remain unchanged.

 

[Livinlocal]

This is actually a very good topic. I have never thought about the test viles freezing during shipment.

 

[Randy Holmes-Farley]

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"

 

[Ehsan@triton]

G´Day Gents....
Hope you alright even knowing its freezing cold at some places over there right now.

Anyway I remember that me and my dad have done some experiments on frozen and heated samples over 6 years ago when we started creating our testing method.
We have found a big difference when using different introduction systems.
I think you can understand that I can not tell you to much about our unique testing method so can not go into to much detail, but I will try to redo some experiments as soon as I can and get you the results.
Our concerns that time has been Macro and Traces but I agree with Randy that traces could be even more effected.

You should but also have in mind that depending on the Sample Introduction system the ICP-OES can also pick-up particles in the sample …. for example Aluminum that you will find in dissolved and particular form.
You can see that by just filtering the sample beforehand.
I remember Randy has done some testing on Aluminum based absorbers on an ICP where you can see that Aluminum is showing up in both forms. It is possible that the low effect on freezing and heating is due to this ability of our introduction System as it can still introduce a quite big particle size into the plasma… but I am not really sure.

So let me check and I or Tim will come back to you ASAP. ;-).

I know my writing might be a bit strange sorry for that.

All the best ....

P.S the relation to Triton comments is very normal as all the new „lab - services“ normaly use our answers for there argumentation ;-).

 

[hart24601]

Would be fun to take 4 samples of tank water, freeze two, thaw and send all 4 in for analysis.

 

[Want2BS8ed]

P.S the relation to Triton comments is very normal as all the new „lab - services“ normaly use our answers for there argumentation ;-).

The open an honest answer is appreciated and it was a good response up until your parting comment.

I was the genesis of your participation in this discussion and I would prefer you answer the question at hand rather than making humorless comments about your competition.

M

 

[Ehsan@triton]

The open an honest answer is appreciated and it was a good response up until your parting comment.

I was the genesis of your participation in this discussion and I would prefer you answer the question at hand rather than making humorless comments about your competition.

M

G`Day and Sorry for that M....
Just wanted to answer to this : “My starting discussion (which also seems to relate to Triton comments)":
We just do our thing here don´t wanted to be disrespectful to anybody trying or doing the same.

 

[Ehsan@triton]

Would be fun to take 4 samples of tank water, freeze two, thaw and send all 4 in for analysis.

You can do that …. and many before have done so in the past…. I think it is valid way especially for yourself to gain real knowledge.

We always say that we are happy people to trust us in what we do and what we say.
But we at Triton try to make it possible that the aquarist at home can find out about things like Salt-quality , Trace-elements , contamination in foods ….. and not need to relay on a company claims.
That is actually why the company was founded for 10 Years ago, and also the reason why we invented the Product „ Lab-Service“ for.

For a test like that the only problem I see to do at home is getting the Trace Elements into the sample …. you could definitely do it with your Tank-water but adding specific trace amounts will get difficult.

The problem is that a lot of traces aren’t stabil in seawater anyway …. like Fe ( Iron ) …. and in standards they will be stabilised in acid wich then will interfere with your results…. but anyway still a good way to get info I think.

 

[Want2BS8ed]

Understood Ehsan. I appreciate the clarification and look forward to the answer to Randy's question.

M

 

[Randy Holmes-Farley]

G´Day Gents....
Hope you alright even knowing its freezing cold at some places over there right now.

Anyway I remember that me and my dad have done some experiments on frozen and heated samples over 6 years ago when we started creating our testing method.
We have found a big difference when using different introduction systems.
I think you can understand that I can not tell you to much about our unique testing method so can not go into to much detail, but I will try to redo some experiments as soon as I can and get you the results.
Our concerns that time has been Macro and Traces but I agree with Randy that traces could be even more effected.

You should but also have in mind that depending on the Sample Introduction system the ICP-OES can also pick-up particles in the sample …. for example Aluminum that you will find in dissolved and particular form.
You can see that by just filtering the sample beforehand.
I remember Randy has done some testing on Aluminum based absorbers on an ICP where you can see that Aluminum is showing up in both forms. It is possible that the low effect on freezing and heating is due to this ability of our introduction System as it can still introduce a quite big particle size into the plasma… but I am not really sure.
.

That sounds good. Thanks.

From your comment on particulates, can you clarify that you do not do anything to remove them from the sample that gets sucked into the machine?

 

[Ehsan@triton]

That sounds good. Thanks.

From your comment on particulates, can you clarify that you do not do anything to remove them from the sample that gets sucked into the machine?

G´day Randy,
Yes i can do that.... we do something to prevent particles to enter the plasma but thats where size really matters. ( Sorry but I have been a bit to imprecise here ).
So normally our countermeasures will hold back sizes low as 10-7 m ( sorry but I dont know to put that upper -7 here) or lets say bigger then 600nm ( nanometers) wich would be Bacteria ( living) , Plant cells and so on. Some viruses would still go trough .

What I meant was smaler particles ( nano size ) since we use them for the SCAN project we have done some experiments with them on the ICP too.
This sizes are things ranging from a single atom to molecules and proteins.
I am doing a interesting experiment right now where we can find out about sizes and even shapes of particles that still will enter the plasma with the use of our introduction system.

Related to freezing I think the size of the possibly formed trace molecules if not exceeding the size of 30nm should be still entering the Plasma and finally be measured wich will give us a theory why the effect is not big in our case.
That said I need to also mention that we use a very unusual and unique introduction system wich we have designed and created in house.
It has the ability to strongly move the Sample before testing ( similar effect of shaking ), wich will get even particular matter into a kind of suspension form and not just leave it sitting on the bottom even being nano size participation.

Just to let you know for now thats just thoughts but i try to point to the direction where i think the scientific answer to that question is.

 

[Randy Holmes-Farley]

Thanks, Ehsan. That clarifies the particulates question for me.

Have you tried freezing a sample down to very low temps (say, -40 deg C) to see if the results after freezing and thawing are the same as before?

 

[Ehsan@triton]

Thanks, Ehsan. That clarifies the particulates question for me.

Have you tried freezing a sample down to very low temps (say, -40 deg C) to see if the results after freezing and thawing are the same as before?

No Problem Randy,
No not shock freezed it jet Randy.
Normal freezing -8 deg C don’t seem to be a problem for the Macros like in the tests 6 years ago so ikaite theory seems to work for us here will post the results soon.... not jet done with the traces.

Do you think very low temps would have an effect or is it more the speed of freezing the sample?
Will need to find a possibility to freeze a sample that low now I guess.

 

[Randy Holmes-Farley]

No Problem Randy,
No not shock freezed it jet Randy.
Normal freezing -8 deg C don’t seem to be a problem for the Macros like in the tests 6 years ago so ikaite theory seems to work for us here will post the results soon.... not jet done with the traces.

Do you think very low temps would have an effect or is it more the speed of freezing the sample?
Will need to find a possibility to freeze a sample that low now I guess.

Seawater may not fully freeze until the temp gets down close to -40 deg C, so that test is more aggressive in terms of forcing precipitation (super high salinity and low temp, both may cause precipitation), and some reefers posting in my forum think their samples may hit -40 deg C in the mail (although why they would want to live there is another question lol)

https://www.sciencedirect.com/science/article/pii/S0165232X99000336

"The model predictions for soluble calcium and sulfate closely follow the Gitterman pathway and culminates in an eutectic temperature of −36.2°C. "

Speed of freezing might be an issue too. I have no idea on that. One of the members is trying his tank water at very low temps and checking visually for precipitates on thawing.

 

[Want2BS8ed]

@Eshan@triton, any progress on the frozen sample issue?

Thanks,

M

 

[Tim@Triton]

We are currently compiling the report, should make interesting reading!

 

[Randy Holmes-Farley]

Thanks.

 

[drawman]

Following.

 

[Want2BS8ed]

We are currently compiling the report, should make interesting reading!

Thanks Tim