Accuracy of Phosphate ICP analysis

[Mortie31]

What is your silicia (Si) levels ?

Sincerely Lasse

318ug/l so a bit high

 

[Lasse]

Adios with that the theory

Can you send a PDF of your values by PM to me - I will try to compare if I can find any compound that can explain my meters reading. The main suspect was Si - but you have higher than me!!!!

Sincerely Lasse

 

[Randy Holmes-Farley Verified Community Expert]

FYI, I read an article a few days ago that indicated that cyclic silicone molecules were the highest indoor air pollutant created in a room full of people. It is present in many personal care products. Folks that get super high Si readings in their tanks may have accumulated these molecules and not silicate.

 

[Lasse]

Thank you @Randy Holmes-Farley

The theory maybe not is completely dead than - but a long shoot. We are two older persons living in my houshold - not using many of the modern personal care products - at least not any that are based on spraying. My Si comes probably from my old experiment with siporex - still a few left in the DSB

Here is my latest ICP test - can you see any compounds that maybe will interfere with the amino acid method?

Sincerely Lasse

 

[pigmo]

I'd personally lean toward Triton too, but I have no proof.

If Triton was higher than might be organic phosphate being read too, but this way around, that can't be the explanation.

we always get triton icp higher than our hanna #s. last month we hanna'd 0.00, and we immediately took a triton sample, which came back at 0.019xx

;Greedy

 

[Mortie31]

Can I ask those who are getting inaccurate results, how old are your checkers? as I’ve just bought a new one and my results correlate with triton perfectly, (this time).. maybe it’s the brand new perfectly clean vials or does the checker have a finite life? I really don’t know just offering suggestions

 

[Lasse]

My is only 3 months old and I have whased my vials with peroxide more than once.

Sincerely Lasse

 

[cjpitt80]

Well got my Triton results back earlier and there identical to my readings, I do like the fast turnaround we get in the UK, these were posted Monday lunch, results friday lunch... maybe new and clean vials and a new device is the key to accuracy...

hmmph VERY interesting that's pretty much Identical! Which checker are you using again? I have the HI-774 ULR phosPHATE checker.

Can I ask those who are getting inaccurate results, how old are your checkers? as I’ve just bought a new one and my results correlate with triton perfectly, (this time).. maybe it’s the brand new perfectly clean vials or does the checker have a finite life? I really don’t know just offering suggestions

My checker is less than 6 months old. And after the first discrepancy, I used brand new vials. Interestingly, last week Hanna PO4 reading was 0.04 (lowest ever recorded on my tank). This is to be expected as I've been dosing NOPOX to keep Nitrates around 2-5ppm. I'll probably do another Triton ICP and compare with Hanna next week or so for fun LOL

 

[Mortie31]

hmmph VERY interesting that's pretty much Identical! Which checker are you using again? I have the HI-774 ULR phosPHATE checker.

I use the ULR phosphorus think its HI-736

 

[cjpitt80]

Update:
So on 12/9 I took a sample with my HI774. Reading was 0.14ppm PO4.
Same day sample was sent to Triton. On 12/14 my Triton testing came in at.... 0.0306 PO4. So....... Same thing. Trend continues, Hanna reads about 4.5x higher than Triton, which seems what everyone else is getting so who knows?? I think I may just ignore PO4 unless it gets above 0.20 on Hanna. I've been dosing NoPOX and following NO3 levels.

I guess biggest surprise was how fast I got my results! I'm in DC and usually it takes a week to 10 days to get my results back. Not sure how/why it was so fast this time esp with it being Christmas time and all the shippers bogged down with Santa gifts.

 

[LARedstickreefer]

Update:
So on 12/9 I took a sample with my HI774. Reading was 0.14ppm PO4.
Same day sample was sent to Triton. On 12/14 my Triton testing came in at.... 0.0306 PO4. So....... Same thing. Trend continues, Hanna reads about 4.5x higher than Triton, which seems what everyone else is getting so who knows?? I think I may just ignore PO4 unless it gets above 0.20 on Hanna. I've been dosing NoPOX and following NO3 levels.

I guess biggest surprise was how fast I got my results! I'm in DC and usually it takes a week to 10 days to get my results back. Not sure how/why it was so fast this time esp with it being Christmas time and all the shippers bogged down with Santa gifts.

They gave you someone else’s test

J/k - That is definitely a short turnaround. Are these tests not having to go to Germany anymore?

 

[taricha]

Excellent point, my friend. I will test and have an answer on Halloween!
An answer for HANNA that is.

Did you ever check this? Tank water PO4 stable in plastic vials like the hach standards? Or does it drop over time?

 

[Lasse]

Update:
So on 12/9 I took a sample with my HI774. Reading was 0.14ppm PO4.
Same day sample was sent to Triton. On 12/14 my Triton testing came in at.... 0.0306 PO4. So....... Same thing. Trend continues, Hanna reads about 4.5x higher than Triton, which seems what everyone else is getting so who knows?? I think I may just ignore PO4 unless it gets above 0.20 on Hanna. I've been dosing NoPOX and following NO3 levels.

I guess biggest surprise was how fast I got my results! I'm in DC and usually it takes a week to 10 days to get my results back. Not sure how/why it was so fast this time esp with it being Christmas time and all the shippers bogged down with Santa gifts.

How does your Aquarium looks like?

Sincerely Lasse

 

[cjpitt80]

Did you ever check this? Tank water PO4 stable in plastic vials like the hach standards? Or does it drop over time?

I did. Unfortunately, I neglected to write the numbers down. I know there was no appreciable difference in the plastic falcon tubes

How does your Aquarium looks like?

Sincerely Lasse

Tank looks OK. There's negligible turf algae and the sandbed isn't completely white, but definitely been worse.

 

[taricha]

I know there was no appreciable difference in the plastic falcon tubes

Fascinating! Thank you. So now we have different people doing the same experiment. In some cases tank water phosphate is unstable when stored, and in other cases tank water phosphate stays steady.
So much for quick, simple answers.
(My wild speculation is that I find it really hard to believe live tank water wouldn't form a biofilm when stored in a container of any kind.)

 

[tastyfish]

Yea I am leaning towards ICP but I do believe there is a definite possibility some is being lossed or fixed or something during transit. For sure on the Hannas, I am very careful with the tests as well. I wear nitrile gloves at all times and wipe the cuvette clean several times during the testing process with a microfiber cloth. I also clean them inside and out before and after every test. Well, i used to, i dont use them anymore.

It can’t be. Unless atomic fusion or fission is going on, which seems unlikely . An ICP measures the elements within a sample. It doesn’t matter which compounds they are locked into, the elements remain the same.

The vial clarity is easily solved with a wipe with kitchen paper and holding the vials at the top. Care when adding the reagent and adhering to the timings of both mixing and the 3 minute sitting period prior to taking the measurement have a big impact on testing accuracy.

I rinse mine with RO after use.

 

[BigJohnny]

It can’t be. Unless atomic fusion or fission is going on, which seems unlikely . An ICP measures the elements within a sample. It doesn’t matter which compounds they are locked into, the elements remain the same.

The vial clarity is easily solved with a wipe with kitchen paper and holding the vials at the top. Care when adding the reagent and adhering to the timings of both mixing and the 3 minute sitting period prior to taking the measurement have a big impact on testing accuracy.

I rinse mine with RO after use.

You are actually incorrect. Depending on the test vial materials, the phosphate concentration can change in transit. I had a discussion with the guy who designed the trident about it (i think, was long time ago. Could have been randy Holmes-Farley or someone else).

 

[tastyfish]

You are actually incorrect. Depending on the test vial materials, the phosphate concentration can change in transit. I had a discussion with the guy who designed the trident about it (i think, was long time ago. Could have been randy Holmes-Farley or someone else).

Unfortunately there are people who will say anything attempt to attempt to discredit competitors and sell more of their product. (Presuming it wasn’t Randy).

Feel free to link to a research paper confirming such, but I would probably want to be a little surer before calling out as “actually incorrect”, this isn’t RC, you know... lol

PS: I have several friends working in Pharma, a research org and a lab testing company. Many run ICP and other spectrometry kit. Non reactive and hydrophobic sample tubes are used, according to the samples to be collected.

 

[BigJohnny]

Unfortunately there are people who will say anything attempt to attempt to discredit competitors and sell more of their product. (Presuming it wasn’t Randy).

Feel free to link to a research paper confirming such, but I would probably want to be a little surer before calling out as “actually incorrect”, this isn’t RC, you know... lol

PS: I have several friends working in Pharma, a research org and a lab testing company. Many run ICP and other spectrometry kit. Non reactive and hydrophobic sample tubes are used, according to the samples to be collected.

.

It was Hans-Werner. It was actually in the beginning of this thread. Here is the quote:

"Phosphate may be adsorbed to the bottles during transportation. We had high losses of phosphate to plastic bottles overnight at low concentrations. I think acidification of the sample is meant to prevent adsorption to bottles."

I actually did research on it back then as well and read about the various rates that certain plastics absorbed phosphate and other things. It was an ocean plastic study but I forget which as it was a long time ago. There is no doubt that certain plastics can absorb phosphate, that is a fact. Whether or not the triton icp vials are made of those plastics or not, I do not know. You would assume not though, however you never know what corners companies are cutting to save money. So you saying "it can't be" is in fact incorrect, because it could be. I was only calling your statement incorrect, which was a direct response to what I said, saying I was incorrect, which may or may not be incorrect.

I'm not interested in debating this further though. Merry christmas!

 

[tastyfish]

.

It was Hans-Werner. It was actually in the beginning of this thread. Here is the quote:

"Phosphate may be adsorbed to the bottles during transportation. We had high losses of phosphate to plastic bottles overnight at low concentrations. I think acidification of the sample is meant to prevent adsorption to bottles."

I actually did research on it back then as well and read about the various rates that certain plastics absorbed phosphate and other things. It was an ocean plastic study but I forget which as it was a long time ago. There is no doubt that certain plastics can absorb phosphate, that is a fact. Whether or not the triton icp vials are made of those plastics or not, I do not know. You would assume not though, however you never know what corners companies are cutting to save money. So you saying "it can't be" is in fact incorrect, because it could be. I was only calling your statement incorrect, which was a direct response to what I said, saying I was incorrect, which may or may not be incorrect.

I'm not interested in debating this further though. Merry christmas!

Thanks for the info, however The vials used are non reactive with seawater or constituent elements. (Confirmed long ago with Triton). The vendor you mentioned earlier had claimed that Trident was more accurate than an ICP as the Ca value varied between a Trident test and the ICP, so when you mentioned Trident, I assumed this to be the same source of “info”...

You can easily verify this (if ultra paranoid) by noting the manufacturer or plastics code on the vials and verifying reactivity.

Sometimes we over think things massively. An ICP is going to be more accurate than a hobbyists’ home test kit.

A valid cause of variation however, would be the presence of different compounds containing Phosphorus, which would skew the results when you perform the PO4 calculation, as it assumes all phosphorus is bound in PO4. Examples of this could be various forms of inorganic phosphorus, which are generally in particulate suspension. In the reef tank, a possible source would be flocculate from Lanathium Chloride dosing.

A 0.2um filter can used to remove such particulate matter prior to the sample being nebulised in the ICP-OES.

Merry Christmas to you, hope you enjoy some great time with the family.