Help Confusing SN test results...

[0siris]

I've just tested my 3 different batches of SN all from different vendors.

They all have in common that while the NO2 levels look as aimed for, the nitrate levels are also high.


Example of one batch, I aimed for 20ppm (in the pic it looks more like 40ppm, but in real it looks close to 20ppm):




This happens with all three batches. Like a nitrate level of 250ppm as shown wouldn't be possible even if it was 100% nitrate since I aimed for only 20ppm?
I also tested the water before, it's distilled and didn't show any nitrite or nitrate.


Blood tests on the other hand look good I think, very dark spots appear where I drop a grain of SN in it. Here's a pic of the same batch as above:

Spoiler

Any ideas how this is possible?


edit: I used this tutorial, but added only 1g to the first glass and transferred 5ml to the second glass to reach 20ppm.

https://sanctioned-suicide.net/threads/testing-my-sn-using-the-aquarium-testing-strips.31522/

 

[0siris]

Update:

So I did some research today and found the following:

Nitrate: Modified Griess reaction
Nitrite: Griess reaction

Chemistry Behind the Test:
Nitrite is detected and analyzed by formation of a red/pink color on the test pad utilizing the Griess reaction chemistry. Nitrate is detected using the same chemistry; however, the Nitrate is first reduced to Nitrite by a reducing agent impregnated in the test pad. The intensity of the color developed is proportional to the amount of nitrite and/or nitrate present.

So basically for the nitrate test the nitrate is first reduced to nitrite, and that probably means the nitrate test also reacts to my nitrite solution because it basically also just measures the nitrite?

Why would they even produce such a test if that's the case.

Anyone with some chemistry knowledge may explain this?

 

[0siris]

Update #2

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tl;dr:
Nitrate levels don't matter on certain test strips.
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Did some more research and am confident in my explanation now.

So:





I found this about my test strips. Basically says if there's any nitrite in the solution, the nitrate reading is useless since it uses the same reaction as said above. (Nitrit is german for Nitrite, it's a typo)


But how exactly comes that it shows a very high nitrate level then if I only have a 20ppm solution?

Well, the 'Modified griess reaction' (reduction of nitrate to nitrite), has a reduction efficiency.
I couldn't find the exact efficiency of this test strips, or any other strips.
But that's probably the answer to my confusing test.
Let's say, for example and simplicity, we need 10 NO3 ions to reduce it to 1 NO2 ion.
So if we had a 10ppm nitrate solution, it would show us 10ppm of nitrate level on the strip (obvious).
But if we now had a 10ppm pure nitrite solution, these nitrite ions could now directly react with the nitrate pad, without having to be reduced and loss of efficiency, so the test would show us a nitrate level of 10x the nitrite level (so 10 x 10ppm = 100ppm).


Very rough estimate of my strips:



Color of nitrite at 40ppm is about the same color as the nitrate at 500ppm (so 12.5 times higher), so the reduction efficiency could be somewhere at 7.5%. (Very rough estimate!).

Which would explain my 250ppm nitrate level at 20ppm nitrite solution in the first post.
20ppm x 12.5 = 250ppm



Please correct me if I'm wrong.

And please share your experiences if you tested your SN, like if you had the same problem or not, because I have seen one test where the nitrate showed 0, but I don't know which brand it was and if it used a different kind of reduction etc.

 

[reticen]

Yeah I just completely ignored these aquarium tests. If the blood is good then it is good.

 

[0siris]

Yeah I just completely ignored these aquarium tests. If the blood is good then it is good.

Wish I could be so chill about it :D