Possible Mechanism for Seachem Prime Detoxification of Ammonia

[Randy Holmes-Farley]

We are having a long discussion in a different thread about if and how Seachem Prime might detoxify ammonia.

I have never understood how the claimed ingredients in Prime (not clearly stated by Seachem, but probably close enough) would actually detoxify ammonia. I said that explicitly in an old ammonia article of mine, not doubting it could work, just not understanding.

In looking in more detail at known possible reactions for that thread, I have developed a hypothesis of how it may work. I wanted to detail it here as a stand alone thread since the other thread is very long and it could get lost in the shuffle there.

https://www.reef2reef.com/threads/does-prime-actually-detoxify-free-ammonia-nh3.849985/ (post #249 duplicates this post)

Here's a hypothesis that may be the reaction of Prime with ammonia based on known literature reactions and the exact composition claimed by Seachem. The product is NH2SO3-, a sulfamate. The reaction is analogous to the reaction with hydroxymethansulfonate, and according to one person writing about this years ago (Boomer), Prime was the Seachem way around the hydroxymethanesulfonate patents (I do not independently know that part)..

Here's the full justified rationale:

Seachem says Prime contains hydrosulfite salts and bisulfite. Hydrosulfite is a chemical synonym for dithionite. Seachem has been adament online that the product does not contain dithionite, despite them seemingly adding it. Why? Perhaps because it decomposes to trithionite as noted below, and trithionite is the actual active ingredient.

A mixture of sodium hydrosulfite (= sodium dithionite) and sodium bisulfite results in a variety of products, including trithionite:

Chemistry of sodium dithionite. Part 1.—Kinetics of decomposition in aqueous bisulphite solutions

The decomposition of sodium dithionite in concentrated bisulphite buffer solutions follows first-order kinetics with an activation energy of 18 kcal/mole. The rate is also first order in bisulphite ion, variable fractional order in hydrogen ion and shows zero salt effect. The reaction...

pubs.rsc.org

"The decomposition of sodium dithionite in concentrated bisulphite buffer solutions follows first-order kinetics........Two sets of stable products, (½Na2S2O3+NaHSO3) and (Na2S3O6), found in ratios between 9 : 1 and 1 : 1, probably result from common intermediates in reaction (3)."

Note that Na2S3O6 is trithionite.

This reference shows that structure for the potassium salt:

https://scripts.iucr.org/cgi-bin/paper?s0567740879008268

Then this reference shows how trithionite reacts with ammonia in aqueous solution to form NH2SO3- (a sulfamate):


THE REACTIONS OF POLYTHIONATES: KINETICS OF THE CLEAVAGE OF TRITHIONATE ION IN AQUEOUS SOLUTIONS

The reactions of polythionates: Kinetic of the cleavage of trithionate ion in aqueous solutions

A kinetic study of the cleavage of trithionate has been made in water over the temperature range of 40–80°C, and in aqueous ammonia solutions over the…

www.sciencedirect.com

"In the cleavage of trithionate in aqueous ammonia solutions, therefore, the following reaction is considered to proceed in parallel with reaction (1) described previously."
S306-- + 2NH3 = S203-- + SO3NH2- + NH4+

 

[a.t.t.r]

Now explain it like my school didn’t have a chemistry class.

 

[jeffww]

That's interesting. So the active compound is generated in situ? I would assume then that trithionites are really reactive reducing agents. In the past I've actually used seachem prime to resolubilize precipitated fertilizer for my freshwater tank. I do wonder what effect these compounds have on livestock then. I personally wouldn't want to add a bunch of reducing agents to my tank...and I wonder how specific the reaction is for ammonia or nucleophiles in general?

 

[Randy Holmes-Farley]

Trithionite is not acting as a reducing agent in its reaction with ammonia. Ammonia is as reduced as a nitrogen compound can get, and the oxidation state of the N in ammonia and in sulfamate is the same (-3).

I'd speculate it could react the same way with primary amines, but do not know if they are stable.

 

[DrZoidburg]

@Randy Holmes-Farley I do like this. I also do see some places where hydroxymethane sulfonate can be an intermediate. I don't think it is as straight forward as this. I see other things that negate this some of this. I will compose a response when I have more time.

 

[Randy Holmes-Farley]

Now explain it like my school didn’t have a chemistry class.

Sorry, it's intended to be a highly detailed description of a hypothesized mechanism

Seachem gives the layman description:

" Prime® does not remove ammonia, nitrite, or nitrate from the system. It simply binds with those compounds making them harmless to the inhabitants and still bioavailable to the beneficial bacteria."

 

[a.t.t.r]

Sorry, it's intended to be a highly detailed description of a hypothesized mechanism

Seachem gives the layman description:

" Prime® does not remove ammonia, nitrite, or nitrate from the system. It simply binds with those compounds making them harmless to the inhabitants and still bioavailable to the beneficial bacteria."

I was joking.

 

[brandon429]

Randy does this mean that when seneye failed to show a measurable change in nh3 after adding prime, that the addition of prime may still be aiding in providing a safety cushion but escaping the measurement ability of seneye?

if I’m not recapping T’s study incorrectly, a big takeaway is that nh3 didn’t change after prime using that device to discern change.

 

[Randy Holmes-Farley]

Randy does this mean that when seneye failed to show a measurable change in nh3 after adding prime, that the addition of prime may still be aiding in providing a safety cushion but escaping the measurement ability of seneye?

if I’m not recapping T’s study incorrectly, a big takeaway is that nh3 didn’t change after prime using that device to discern change.

I'm not sure how to interpret seneye results with Prime, either with this possible mechanism, or without, because I'm not sure what impact these nitrogen compounds may have on ammonia detection mechanisms.

 

[Malcontent]

I think the idea is that a hydrophobic membrane (PTFE, etc.) allows NH3 to pass through but not NH4 and/or bulkier bound ammonia.

And gills are analogous to these hydrophobic membranes.

 

[ingchr1]

Randy does this mean that when seneye failed to show a measurable change in nh3 after adding prime, that the addition of prime may still be aiding in providing a safety cushion but escaping the measurement ability of seneye?

if I’m not recapping T’s study incorrectly, a big takeaway is that nh3 didn’t change after prime using that device to discern change.

I had a similar question in the other thread that went unanswered.

.....When ammonia and nitrite are in the bound state how is each measurement method affected? Would each method measure the same amount, or should binding result in a lower measurement?

 

[Lasse]

IMO - either will seneye and ammonia alert also react to other - non toxic forms of N - or Prime does not work. Both statements can´t be true - IMO

Sincerely Lasse

 

[Theulli]

I don't use Prime to detoxify my tank, I've got one of these mugs:

 

[taricha]

I had a similar question in the other thread that went unanswered...
.....When ammonia and nitrite are in the bound state how is each measurement method affected? Would each method measure the same amount, or should binding result in a lower measurement?

here's Prime interfering with NO2 test in this post
and here's Prime interfering with total ammonia and NO3 chemistry in this post

The NH3 sensing films are unaffected - they do not measure a decrease in NH3, which is why I described the above test results as interferences with the test kits rather than actually lowering those concentrations.

 

[DrZoidburg]

@Randy Holmes-Farley
All of these are if this ingredient started with dithionite. Like you say though they claim it is not.

1: Unknown equilibrium products, and unknown intermediates in bottle versus kinetics decomposition research paper with zero salt effect. This could create different paths. Dithionite will react with water, air, impurities, and trace metals. Also possibly autocatalytic oxidation reactions. Into stranger unpredictable ratios. "sodium dithionite must be handled strictly in an anaerobic environment due to its sensitivity towards oxygen. Analytical procedures which require removal or transfer of its solutions is therefore susceptible to serious error" Even in making product, if opened, or stored for time. To say it ends as 9:1 to 1:1 in prime bottle may or may not be true. I am skeptical of this being a determining factor. I suspect though it would be similar to trying to ID a specific polysulfide, in a mixture where there can be vast different ones. Sometimes very hard. It would depend a lot on the variables when they reacted this, the moment closed the cap, and even the water you are testing. It would have to be very precise, and consistent. Many unknown factors but with more info we could speculate.

2 If it does create substantial trithionite at 1:1. We could send this further. If it ends closer to 9:1 ratio then I feel it would not have great effects. Could maybe test this ratio/ingredients with iodine.

3 Yes crystal structure ID in other paper of trithionate, not specifically in primes case. How stable though at neutral+ ph vs temp. Seachem claims it is not acidic, and should not effect ph of aquarium. It would have to be slightly higher ph to be completely stable for some of these intermediates.

3 Reaction of cleavage at 40 - 80C versus occurring in aquarium at 25 degrees C +/-
- cant read whole paper only the abstract.
- unknown pressure in test cant calculate reaction rate, or equilibrium products.
- unknown concentrations
- constant also relies on metastable oxyanions in a presumably very controlled reaction
- also says one was conducted in ammonia solutions, and one in water. Not in a living environment.
- dithionite not as stable in decreasing ph either. Starting around 11 and less.

4 If the end product was however NH2S03 + NH4, or with any NH3S03. Both of these products can continue to hydrolyze into other products possibly before it hits all ammonia. Reactions can occur with some organic sources, from foods, fish waste, and can also with alcohols. Like in a case where someone is carbon dosing. Possibly medicines. (some places claim no toxic polymerization) There are patented documents for solubilizing polymers with this. It is also known to be somewhat toxic, and create other esters. Some of the species after sulfamate reactions wouldn't directly stop reacting either. Like mentioned in other thread some of these reactions can be catalyzed in alkaline environments in the presence of both cations, and the anions. The NH2SO3 itself can also be both a catalyst and catalyzed. Honestly I think they would not use this exact mechanism. A pathway diagram would be huge.

- to many possible side products to be safely reliable
- organometallics possible in many of these steps
- some not that toxic
- some are very toxic
- Logically though in my opinion it would be better to use products found much after hydrolysis. Possibly even alternative methods. Doing it that way would avoid many toxic species, have less pathways, and less unpredictable reactions.
- will it work in my opinion maybe so at what rate and valuable percentage.
- I actually can test this I have sulfamic acid Will do this even though I fear it wont prove much.
- I also fear salicylate based test kit will interfere and not prove anything completely useful.
- Only currently have api, and sera kits. Both are salicylate based.
- Because the way those test work. It creates 2 particular compounds that will make many of the end, and side products known chelating agents, reactive species, and some that create ligands.
- If the reagents in test kits are in excess. It will bind the compounds. Showing staying color in test. If ammonia however is in excess, you may see a reduction in color change. With common brand reducers people can view this.
- Also depends on if compound is reactive with reagent. Some you will see do this some you may not. I Have a feeling sulfamate and ammonia reaction may. If it does not however, this would prove it is not the ingredient. If it does realistically we are at square 1 or 100.
- I found it can be mitigated by sulfuric acid. However It creates a off color that is different. Would have to design a new color chart just for this.
- Even if ingredients in reducers are different. Like mentioned above many of these compounds will bind with reagent biproducts anyway.
- Currently conducting tests more on this later.

 

[taricha]

Then this reference shows how trithionite reacts with ammonia in aqueous solution to form NH2SO3-

I actually can test this I have sulfamic acid

Funny you mention that...

 

[DrZoidburg]

@taricha Disclaimer one of these compounds contain cyanide. If you get any funny ideas please be careful.

 

[Randy Holmes-Farley]

Sulfamic acid is a standard used in many acid titrations, and like the above product picture, it is sometimes marketed as a safer alternative to muriatic acid for cleaning surfaces.

It may or may not be a product produced by Prime, but nothing I read above says it cannot be.

 

[Randy Holmes-Farley]

All of these are if this ingredient started with dithionite. Like you say though they claim it is not.

Seachem does not, as far as I have seen, say they do not use dithionite in the product

The one document I have seen:

5.5.3.2.3. Prime, Safe and Sodium Dithionite

Seachem Prime and Safe are only the chemical sodium dithionite.

aquariumscience.org

says

"Sodium dithionite is not in the products."

Seachem typically obscures what is in their products with vague or nonstandard chemistry names, but the product could easily be as I describe and fit the literal words written in at least three different ways:

1. It need not be sodium dithionite they use. Might be potassium or calcium, etc.
2. Like any salt, once sodium dithionite dissolves, there is literally no sodium dithionite in the product. It is sodium ions and dithionite ions.
3. If the dithionite reacts as I state, there may be none "in" the product. It was used to make the product, but is not in it.

 

[Dan_P]

I'm not sure how to interpret seneye results with Prime, either with this possible mechanism, or without, because I'm not sure what impact these nitrogen compounds may have on ammonia detection mechanisms.

We also failed to detect Prime reducing free ammonia concentration with Seachem colorimetric films in their ammonia test kit and the ammonia alert badge. Seachem says these products detect free ammonia and can be used to observe Prime working. The conclusion is the same using Seneye or Seachem colorimetric films: Prime does not neutralize, combine with or detoxify ammonia in saltwater. And I will go out on a limb and say the similar claim about reducing nitrite and nitrate concentration is nonsense.

At this point a reaction mechanism that explains why Prime does not work in saltwater would be more useful.
.