Help Has my previously strong SN now degraded?

[autumnal]

OK, I'm a little confused here.

Back on 14 February I tested my SN using the aquarium method but with slightly sub-optimal methodology (spring water rather than distilled, 250ml water only, 3g of SN rather than 2.5g) as described here. The test strips showed the highest possible concentration of Sodium Nitrite being 80mg/L. So this was an awesome result, even bearing in mind any methodological limitations.

Before testing, the SN was transferred from the ziplock bag it arrived in, into a sealed plastic Tupperware container. The container held the 200g of SN and was around 1/3 full, so 2/3 of the space was empty air. I also put in a desiccant packet I had spare, to help absorb any moisture. The container was kept in a dark cupboard away from light and any temperature extremes.

Today I decided to retest, now having access to distilled water, more precise scales and larger container sizes. I followed the PPH method exactly as described here. This time I got vastly different results. Bottle 1 (not meant for testing but I did anyway) had a concentration of 10mg/L and Bottle 2 was only 5mg/L.

Puzzled by these results being vastly lower than the previous occasion, I mixed up a fresh batch of solution using lethal quantities, that is 35g of SN in 100ml tap water (I had used up all my distilled water in the previous tests). When tested, this mixture was only 1mg/L!

So my questions are:

1. Has my SN degraded over the time between the first and second testing occasions?

2. Based on the level in Bottle 2 of only 5mg/L, is my SN now insufficient for lethal purposes?

3. How is it possible that a lethal dose of 35g/100mL tap water can have a lower concentration of SN (1mg/L) than the heavily diluted amount in Bottle 2 did (5mg/L)?

4. If the SN has degraded, is it because there was too much empty air space in the container for it to react with? If I need to get a new batch, should I be vacuum-sealing it instead? I do have one of those Tupperware containers that you attach the vacuum pump to and pump the air out. Could the dessicant packet have done something?

Thanks in advance for any advice.

 

[Letmego. Please]

Have you repeated your original test with spring water? no idea if that would make a difference but worth a try, sorry no idea on the rest.

 

[rntmss]

There's no reason for it to degrade that quickly if there was no air in the container. That's bizarre.

was it a good quality container? Was it brand new? Maybe the plastic was worn or broken down at a very microscopic level and let air in

 

[ashwin]

will it be ok to open the bottle test it and then close it again.. if the air entered at this time will cause any issues ?

 

[Letmego. Please]

There's no reason for it to degrade that quickly if there was no air in the container. That's bizarre.

was it a good quality container? Was it brand new? Maybe the plastic was worn or broken down at a very microscopic level and let air in

If it was a third full then there was always going to be air in the container

 

[rntmss]

If it was a third full then there was always going to be air in the container

I really only have a basic high school chemistry knowledge, but once that oxygen inside the sealed container has reacted with the SN... it can't react again. So yes, some of the SN will react and turn into Nitrate... but that should be negligible since eventually all the oxygen in the container is used up and there's no source for more.

 

[TelstraSuckAFatOne]

You've made me paranoid now thinking the SN I've purchased will be no good. I think we come from the same part of the world but we didn't get it off the same supplier. I opened mine the other day and it looked fine but now I'm concerned just by opening it that I've ruined it. I will do a blood test the day I plan to ctb just to see if it goes dark brown. I hope you get yours sorted too such a pain in the ass that it can go bad so easy.

 

[Letmego. Please]

I really only have a basic high school chemistry knowledge, but once that oxygen inside the sealed container has reacted with the SN... it can't react again. So yes, some of the SN will react and turn into Nitrate... but that should be negligible since eventually all the oxygen in the container is used up and there's no source for more.

Then you have better chemistry knowledge than I, apologies was just answering the question, as it's not my subject of interest as such I have no idea how it might degrade. Was just interested in if the original experiment had been repeated in the same way.

 

[k75]

Not an expert, but I suspect a few things might be at play.

Maybe your testing supplies and not the SN are bad.

Maybe the testing method isn't as accurate as people think. It's not exactly a lab test, after all.

Or maybe you're getting different readings because your testing solutions are different. You said your first test was with a different water. That could affect the results.

Or maybe it really has degraded that much, but that's a drastic change and I doubt it.

 

[seafarer]

Only thing would be to test again to confirm results. Latest test could have an a calculation error that you have missed while doing likewise so could have the first test. So one more test and be extra meticulous and see how that goes

 

[autumnal]

Thanks guys, will test again tomorrow using the spring water and see if that makes any difference. Will let you know the results.

The test strips are proper scientific ones, not just aquarium grade.

 

[seafarer]

Cool would be interesting to see how it goes. Also since different test strips maybe just double check that are set up to test for the right thing. Sounds stupid I know ,I have never tried this method but I'm assuming it's testing for either sodium or nitrates etc and isn't just a pH test. Last comment may make me sound stupid are fair enough but if that is one thing that changed from first test it's logical to make sure they are fit for purpose and maybe even get the aquarium test strips also for a test and rerun that the same to see if the results change based on strips from test kit being the only variable. Also main reason for all this is it will help put your mind at rest and worrying about this one issue which I know from experience one nagging issue can avalanche into a meltdown. Good luck

 

[jgm63]

It's good to try to figure this out.
But I shouldn't worry excessively.
The dosages in Stan's guide are around 2.5 times the lethal dose.
So there's plenty of room for error built in....

Provided your SN still passes the "blood test" with ease, then I think it's fine....

I suppose if you still felt uneasy you could always up the amount a little, but probably not too much....

 

[autumnal]

OK folks, so as suggested I retested today using spring water to duplicate the conditions of my first testing occasion.

Followed PPH method exactly with the exception of using 600ml water (the size of the bottles it came in) rather than 1L. Still used 5g SN and still transferred 2ml solution between the bottles. On this occasion I first shook up the container of SN to mix it thoroughly, in case the layer on the surface had become degraded due to mixing with air. On the two previous testing occasions I did not shake the SN, but I did spoon it out in such a way that both surface SN and a good amount below was gathered.

Note that my test strips test both Nitrite (NO₂, the good one for our purposes) and Nitrate (NO₃ , the bad one for our purposes) as separate chemicals. Note that unfortunately I didn't bother testing Nitrate levels back on the first testing occasion or the second one. But I did today. Results as follows:

	Nitrite (NO₂) (mg/L)	Nitrate (NO₃) (mg/L)
Bottle 1	5	25
Bottle 2	20	250

I also made up a lethal mixture again, 35g SN in 100ml water. This time the lethal mixture was shaken up in the bottle, rather than just well-stirred as on the previous occasion,

	Nitrite (NO₂) (mg/L)	Nitrate (NO₃) (mg/L)
Lethal mixture	1	25

Note that I ran all of these tests twice and the results were unchanged.

So now Bottle 2 seems to score well for Nitrite, albeit much less well than it did on the first testing occasion.

The ratio between Nitrite and Nitrate is also consistent across Bottles 1 and 2.

But Bottle 2 should by definition be less concentrated than Bottle 1, so why on earth is it scoring higher for Nitrite (and also for Nitrate)?

And the Lethal mixture should be far more concentrated than either bottle, yet it scores the lowest for Nitrite of all the mixtures!

The whole thing has me so puzzled that I've ordered two more fresh batches of SN from the same supplier. When they arrive, I'll probably test one batch but leave the other batch untouched in its original packaging and only open and test it on the evening of my attempt.

Anyone who can shed any light on this whole situation would be most appreciated!

P.S. More like damn confusing science!

 

[TelstraSuckAFatOne]

Keep us updated on the next results please.
Thank you

 

[autumnal]

Oh apparently my earlier link to the test strips is now showing an error page..




This is info on what they are. They are ages away from their expiry date and have been kept sealed in normal conditions.

 

[jgm63]

As a general rule, whenever using strips of that kind, I would always think it would be better to aim to get results around the middle of the strip test range.
If you get a test result at the "edge" of the strip, eg the max, then to me it reduces confidence in what I would be seeing (eg I would be thinking, could it in fact be significantly higher than the max, in which case did I make a mistake measuring things out, etc, etc).

So my approach would be to use amounts that should hopefully take me somewhere around the middle of the test strip, if the SN were pure.
( or I suppose you could aim to be at 75% of the test strip, that would work as well, and perhaps gives you more scope to detect how far under the expected amount you are ).

Also, what happens when using those strips with concentrations that are way higher than those strips can register ?

Do the strip instructions state what happens for those cases ?
(Otherwise there is no meaning in doing your lethal dose tests).

In general, however, the number of contradictions in some of your results leads me to think you must somehow be doing something wrong, or that the test strips are somehow flawed...
Perhaps it might be an idea to buy a few different brands of cheaper test strips, since super accuracy isn't really needed....

When doing things like this, I think the first point at which you find something weird, you need to stop and figure out what's going on.
Trying to continue and do further tests is pointless until you work out what that first weird thing is.....

 

[autumnal]

As a general rule, whenever using strips of that kind, I would always think it would be better to aim to get results around the middle of the strip test range.
If you get a test result at the "edge" of the strip, eg the max, then to me it reduces confidence in what I would be seeing (eg I would be thinking, could it in fact be significantly higher than the max, in which case did I make a mistake measuring things out, etc, etc).

So my approach would be to use amounts that should hopefully take me somewhere around the middle of the test strip, if the SN were pure.
( or I suppose you could aim to be at 75% of the test strip, that would work as well, and perhaps gives you more scope to detect how far under the expected amount you are ).

Also, what happens when using those strips with concentrations that are way higher than those strips can register ?

Do the strip instructions state what happens for those cases ?
(Otherwise there is no meaning in doing your lethal dose tests).

In general, however, the number of contradictions in some of your results leads me to think you must somehow be doing something wrong, or that the test strips are somehow flawed...
Perhaps it might be an idea to buy a few different brands of cheaper test strips, since super accuracy isn't really needed....

When doing things like this, I think the first point at which you find something weird, you need to stop and figure out what's going on.
Trying to continue and do further tests is pointless until you work out what that first weird thing is.....

Thanks for the advice. From what I can tell I'm following all the instructions exactly, but clearly there are some paradoxical results so something must be wrong somewhere.

The instructions are attached, they mention the detection range of the strips and the possible interferences, does that mean anything to you or anyone else with scientific experience?

.

Have literally followed the exact steps (with any exceptions detailed) as described in my first post of this thread and the links to other posts therein.

 

[jgm63]

Before reading the explanations below, you should first read this :
https://sanctioned-suicide.net/threads/sn-aquarium-purity-testing.34630/
Read until the end of the first "method 1" section - don't need to read the whole thing.


"Back on 14 February I tested my SN using the aquarium method but with slightly sub-optimal methodology (spring water rather than distilled, 250ml water only, 3g of SN rather than 2.5g) as described here. The test strips showed the highest possible concentration of Sodium Nitrite being 80mg/L. So this was an awesome result, even bearing in mind any methodological limitations."

> I've discussed those results on that thread.

"Today I decided to retest, now having access to distilled water, more precise scales and larger container sizes. I followed the PPH method exactly as described here. This time I got vastly different results. Bottle 1 (not meant for testing but I did anyway) had a concentration of 10mg/L and Bottle 2 was only 5mg/L."

> Bottle 1 should have contained 5g in 1 litre, IE 5g/L. That should have been "off the chart" for your test kit. Do we know what your test kit does for very high concentrations ? It would seem it doesn't display anything meaningful for those cases.

> Bottle 2 should have contained 10mg in 1 litre, IE 10mg/L. You saw 5mg/L. Perhaps there is just a general margin of error in the test strips, which is perhaps likely, considering the nature of checking colours is approximate.... (Or this could have been caused by accidentally transferring 1ml over instead of 2ml)

"Puzzled by these results being vastly lower than the previous occasion"

> Hopefully at this point you can understand why you have the lower result of 5mg/L this time, compared with the higher results you saw during your first tests. During your first tests, you were getting a "x16" effect, as explained in my reply on that thread.
So perhaps "by accident" that method was fairly well suited to the "range" of the test strips you were using.
Whereas this time, by following the PPH, you are using a method designed to be used with 10 mg/L test strips, IE a method that deliberately creates a lower concentration solution.

Once you understand how these tests work (which you now do if you read the thread I mentioned above), and can follow some of the calculations, then these points should become clear.

So the lower values seen now compared with previous tests, are simply due to the amounts (ml of water / g of SN / ml of water transfer) you are using to test with, which "create" the final concentration. In previous tests the amounts used created a higher concentration. In these more recent tests, the amounts used create a lower concentration.

"I mixed up a fresh batch of solution using lethal quantities, that is 35g of SN in 100ml tap water (I had used up all my distilled water in the previous tests). When tested, this mixture was only 1mg/L!"

> This solution was 350g/L, or 35000mg/L. Goodness knows what the test strips would make of that...
Perhaps the test strip "caught the bus" : ¬ )

"1. Has my SN degraded over the time between the first and second testing occasions?"
> No, the main issue is the change of test method.

"2. Based on the level in Bottle 2 of only 5mg/L, is my SN now insufficient for lethal purposes?"
> No, it's probably fine, but more tests should be done. See below.....

"3. How is it possible that a lethal dose of 35g/100mL tap water can have a lower concentration of SN (1mg/L) than the heavily diluted amount in Bottle 2 did (5mg/L)?"
> See above.


As discussed on the other thread, if you're using 80mg/L test strips, then you need a test method designed to target those test strips....
Namely :
> Use 1 litre of water in each "cup" (actually, you would perhaps use bottles rather than cups)
> Use 10g of SN, and transfer 4ml from cup/bottle 1 to cup/bottle 2.
> This would mean you end up with about 40mg/L if the SN is 100% pure.
As discussed on that thread, this is designed to target the middle of the test strips....

NOTE : The best way to understand this testing method in general is to read :
https://sanctioned-suicide.net/threads/sn-aquarium-purity-testing.34630/

So, perhaps you could try again, using the 1L / 10g / 4ml testing setup mentioned above....

-----------------------------------------------------------------------------------------

Also.... Looking at your other test, based on : 600ml / 5g / 2ml
5g in 600ml will give 8.33g/L calculation : (5 / 600) * 1000
Taking 2ml of that will give 2 / 1000 * 8.33g = 0.0166g or 16.6mg
Putting 16.6mg in 600ml, will give : (16.6 / 600) * 1000 = 27.66 mg/L
This seems to be roughly what you saw for your "bottle 2" result.
If the 20 mg/L you observed were accurate then it might suggest your SN is 72% purity ( (20/27.66) * 100 ).
I suspect the accuracy may not be that high, and perhaps the purity is actually higher, but testing that targets the middle of the test range should give a better accuracy. It can be followed up by testing the targets the max, to get an even more accurate percentage purity measurement.

As explained above, the lower values seen now are due to the amounts (ml of water / g of SN / ml of water transfer) used to test with, which create the final concentration....

For bottle 1, I think we have the usual "off the charts" issue (test strip RIP/CTB), so I would not pay attention to that result.

As already discussed, the "lethal mixture" measurement is another "off the charts" case.

Any questions, let me know....

 

[autumnal]

[...]
As discussed on the other thread, if you're using 80mg/L test strips, then you need a test method designed to target those test strips....
Namely :
> Use 1 litre of water in each "cup" (actually, you would perhaps use bottles rather than cups)
> Use 10g of SN, and transfer 4ml from cup/bottle 1 to cup/bottle 2.
> This would mean you end up with about 40mg/L if the SN is 100% pure.
As discussed on that thread, this is designed to target the middle of the test strips....
[...]

@jgm63, many thanks for all the info. Can you please reword those instructions/numbers for a 600ml bottle size, as that is what I have available for testing. And I'm presuming the use of tap water or spring water won't have a significant influence on the results as opposed to the ideal of distilled water?

 

[jgm63]

@jgm63, many thanks for all the info. Can you please reword those instructions/numbers for a 600ml bottle size, as that is what I have available for testing. And I'm presuming the use of tap water or spring water won't have a significant influence on the results as opposed to the ideal of distilled water?

I've written a post that covers the "mathematics" of the test method :
https://sanctioned-suicide.net/threads/sn-aquarium-purity-testing.34630/post-644587

Applying the maths to your case...

I'll assume we're "targeting" the *middle* of the test range.

600ml of water in bottles 1 and 2, and use 1g of SN.
Our test kit can measure up to 80 mg/L.
Target the middle, ie 40 mg/L
How much transferred volume of water should I use ?

v1 = 600 v2 = 600 w = 1000 tc = 40 / 1000 = 0.04
(Convert from mg/L to mg/ml, so divide by 1000. Convert volumes to ml, and weight to mg, so those are multiplied by 1000)

t is what we're trying to determine, so use equation for t :
t = ( tc * v1 * v2 ) / w
So :
t = ( 0.04 * 600 * 600 ) / 1000 = 14.4 ml

So, we've determined we should transfer 14.4 ml of water from bottle 1 to 2.
If the SN is 100% pure, then this should give a 40 mg/L result on the test kit.

However, perhaps your scales are more accurate than your syringe ?
Then an alternative is to transfer 10ml of water, and calculate the required weight of SN...

So :
600ml of water in bottles 1 and 2, transfer 10ml of water
Our test kit can measure up to 80 mg/L
Target the middle, ie 40 mg/L
How much SN should I use ?

v1 = 600 v2 = 600 t = 10 tc = 40 / 1000 = 0.04

w = ( tc * v1 * v2 ) / t

w = ( 0.04 * 600 * 600 ) / 10 = 1440 mg = 1.44g

So, we've determined we should use 1.44g of SN.
If the SN is 100% pure, then we should see 40 mg/L on the test kit.

(and if you wish you could do an additional test to target the max of the test range, by using 2.88g of SN)

 

[jgm63]

p.s. Please keep us updated if you do any further tests....

 

[Bob_Luman]

I live with my parents still so does anybody know where I should store the SN on arrival that won't ruin it and cause it not to be usable? As I plan to use the SN the day I get it but probably early hours of the next morning when everyone is sleeping and eight hours will have passed without eating from the evening.

 

[autumnal]

p.s. Please keep us updated if you do any further tests....

@jgm63 , I tested the same batch of SN today with a new bottle of test strips.

600ml bottles of spring water, 1.44g SN, 10ml transferred from Bottle 1 to Bottle 2, aiming for 40 mg/L range of test strips per your instructions above.

	Nitrate (mg/L)	Nitrite (mg/L)
Spring water (control)	10	1
Bottle 1	500	40
Bottle 2	250	20 / 40 (two tests, visibly borderline)

Are those high levels of Nitrate to be expected, or do they indicate deterioration?

From the borderline Nitrite results, can I assume my SN is between 50-100% pure?

Your thoughts?

Am also expecting a new batch of SN from a different supplier, hopefully when it arrives it will test more definitively.

 

[jgm63]

@jgm63 , I tested the same batch of SN today with a new bottle of test strips.

600ml bottles of spring water, 1.44g SN, 10ml transferred from Bottle 1 to Bottle 2, aiming for 40 mg/L range of test strips per your instructions above.

	Nitrate (mg/L)	Nitrite (mg/L)
Spring water (control)	10	1
Bottle 1	500	40
Bottle 2	250	20 / 40 (two tests, visibly borderline)

Are those high levels of Nitrate to be expected, or do they indicate deterioration?

From the borderline Nitrite results, can I assume my SN is between 50-100% pure?

Your thoughts?

Am also expecting a new batch of SN from a different supplier, hopefully when it arrives it will test more definitively.

Sorry, only just noticed this.....

There isn't much logic to measuring the nitrite level in bottle 1, based on the test kit you are using.
It would be "off the charts", unless the SN were almost completely degraded, and it's going to be hard to know what you're really looking at in terms of results.
I would stick to measuring bottle 2, as per the test method.

In terms of the bottle 2 results....
I don't quite follow what "visibly borderline" means ?

So you saw 20 mg/L for the first test, and 40 for the second ?
Did you use two test strips on the same solution ?
Or repeat the whole test twice ?

If you used two test strips on the same solution, but got very different results, then it suggests the test strips are unreliable.

If you repeated the whole test twice, but got different results, then it suggests the SN is significantly weaker / stronger in different parts of your SN.
I suppose if the second sample were from "further down" in the container, then this might tally with what has been observed, if that SN had not been exposed to air ?

Regarding the nitrate levels, I'm not sure.
For now, I think we should focus on the nitrite levels....

Perhaps it might be an idea to order some alternative test strips, in case the ones you have are not reliable ?
Some cheap ones might be okay....
Don't worry about getting ones that match the concentration levels of the ones you already have.
We can do another calculation easily enough, to get some alternative quantities to be compatible with the new strips....
(You can just let me know what concentration the new strips measure to, plus confirm again what water volumes you will be using).

EDIT :
Or perhaps you just meant that the results seem to be between 20 and 40 mg/L.

In this case, you could repeat the test, and use 2.88g SN, to try to target the max end of the test strips.
This may help you get a more accurate reading.....

 

[autumnal]

EDIT :
Or perhaps you just meant that the results seem to be between 20 and 40 mg/L.

In this case, you could repeat the test, and use 2.88g SN, to try to target the max end of the test strips.
This may help you get a more accurate reading.....

Yeah it was that, visibly borderline coloured/hard to distinguish.

 

[jgm63]

Yeah it was that, visibly borderline coloured/hard to distinguish.

ok, sure....
Well, the test you have done shows that your testing method is working, and you are executing the test correctly.....
I would suggest repeating the test, using double the SN amount, so 2.88g.
This should now give 80 mg/L if the SN is 100% pure....