Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: scientizscht on 24/12/2020 18:50:42
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Hello!
For reactions that occur inside water solutions and have oxygen as one of the substrates, how much does oxygen limit these reactions?
Oxygen inside water is normally very low and also the oxygen from the atmosphere does not easily diffuse inside the water to replenish any consumed oxygen.
Can you help me please estimate what is the bottleneck that oxygen poses for oxygen consuming reactions inside water solutions?
Thanks!
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Life is one of those "reactions" that occurs in water.
Cold water can hold more oxygen than warm water, so as the oceans warm due to human activities, the amount of life the oceans can sustain will drop. (...not helped by overfishing!)
See: https://en.wikipedia.org/wiki/Oxygen#Physical_properties
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Life is one of those "reactions" that occurs in water.
Cold water can hold more oxygen than warm water, so as the oceans warm due to human activities, the amount of life the oceans can sustain will drop. (...not helped by overfishing!)
See: https://en.wikipedia.org/wiki/Oxygen#Physical_properties
Thanks for the information but not really helpful.
I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.
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I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.
It depends.
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I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.
It depends.
Everything depends. Any indications?
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Any indications?
No, you have not provided any indications.
Would you like to, or is this another of your posts where you ask a stupidly open question then get upset when it's impossible for anyone to answer.
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Any indications?
No, you have not provided any indications.
Would you like to, or is this another of your posts where you ask a stupidly open question then get upset when it's impossible for anyone to answer.
You equally do not indicate what more information you need.
There are tons of such enzymes and reactions, I do not have a specific in mind.
One example would be glucose oxidase. In a glucose solution of 100mM, the oxygen dissolved would be 0.22mM. The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?
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The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?
And the answer is also simple.
It depends.
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The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?
And the answer is also simple.
It depends.
On what and how?
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On what and how?
Guess.
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In refusing to give a straight answer to the OP's question, posters are merely displaying proper scientific caution.
Which is admirable, though not very helpful perhaps
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In refusing to give a straight answer to the OP's question, posters are merely displaying proper scientific caution.
Which is admirable, though not very helpful perhaps
Actually I'm trying to teach the OP to ask better questions.
He has a tendency to ask things which, to answer fully, would need a book or two.
For example, a full reply to this thread would need a good understanding of enzyme kinetics and of diffusion.
It's unrealistic to imagine that someone is going to provide that here.
The OP would do much better by learning science from the Khan Academy or some such.
This has been pointed out before, but he persists in asking absurd questions.
You could help me by letting me know if this explanation made sense to you.
It could be that I'm not making myself clear to the OP.
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My question has several assumptions which are easy to assume.
E.g. we have glucose oxidase in a still solution with glucose. Let's say we have 10,000 units and the concentration of glucose is 10mM. The question is, will oxygen diffuse from air into the water and react with the enzyme or this will not be enough and the enzyme will be restricted?
I am assuming room temperature, normal atmosphere, etc etc. I am not referring to extreme situations where we have 5kg of enzyme per litre or superheated water etc.
If the answer depends, I am asking what conditions would oxygen start limiting the reaction.
I do not understand what you find unanswerable in my question.
Of course, it will need to read 2 books to answer this but I don't want the answer to be two books, I want the conclusion from people who have relevant knowledge and experience or can provide estimates.
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I want the conclusion from people who have relevant knowledge and experience or can provide estimates.
That is clearly not true.
Because you have been given that answer twice,.
Here it is for the third time
Quote from: Bored chemist on 26/12/2020 14:56:09
It depends.
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The question is, will oxygen diffuse from air into the water
Obviously, yes
Life is one of those "reactions" that occurs in water.
A lot of "life" involves the enzymatic oxidation of glucose.
But you didn't want that answer either.
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The question is, will oxygen diffuse from air into the water
Obviously, yes
Life is one of those "reactions" that occurs in water.
A lot of "life" involves the enzymatic oxidation of glucose.
But you didn't want that answer either.
I obviously know that but I am not sure if it is representative of regular lab conditions, i.e. considerable glucose concentration and considerable enzyme concentration. Also, oxygen is heavily facilitated and transported and stored in cells so I do not think that a living organism oxidising glucose is representative of a 50mM glucose solution with 10,000 units of enzyme under ambient air and no stirring.
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Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?
What are you actually trying to find out?
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Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?
What are you actually trying to find out?
Never come the raw prawn with Bored. He knows all the lurks.
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Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?
What are you actually trying to find out?
I put glucose oxidase in an unstirred glucose solution under ambient conditions and no glucose reacted. I want to know if oxygen is responsible for that.
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no glucose reacted
How do you know?
But, the most likely answer is that diffusion from the air into your reaction vessel was too slow.
Did you put the solution in a shallow flat tray, a beaker or a conical flask?
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no glucose reacted
How do you know?
But, the most likely answer is that diffusion from the air into your reaction vessel was too slow.
Did you put the solution in a shallow flat tray, a beaker or a conical flask?
I measured glucose with HPLC. Could it be a possibility that glucose and gluconate where measured together? I have not been able to find online whether HPLC can distinguish between glucose and gluconate.
The reaction took place in a square beaker and the solution had a square shape.
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I have not been able to find online whether HPLC can distinguish between glucose and gluconate.
Well, it would if I was doing it but it seems that you don't know how, because, if you did, you would have checked that first.
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I have not been able to find online whether HPLC can distinguish between glucose and gluconate.
Well, it would if I was doing it but it seems that you don't know how, because, if you did, you would have checked that first.
How would you do it? Do you use special columns or methods?
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The first thing I would do would be google it and see if someone has done it before.
Something like this
https://www.shodexhplc.com/applications/lc-ms-analysis-of-glucose-and-gluconic-acid-vg-50-2d/
The other thing I would do would get a sample of the gluconic acid.
That way I could measure it as well as measuring glucose.
If, for example, 1% of your glucose is oxidised, it will be difficult to measure the change in concentration- especially as there will be some evaporation when the material is exposed to the air.
But if 1% of the glucose if converted to the acid, you will see the acid easily.
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The first thing I would do would be google it and see if someone has done it before.
Something like this
https://www.shodexhplc.com/applications/lc-ms-analysis-of-glucose-and-gluconic-acid-vg-50-2d/
The other thing I would do would get a sample of the gluconic acid.
That way I could measure it as well as measuring glucose.
If, for example, 1% of your glucose is oxidised, it will be difficult to measure the change in concentration- especially as there will be some evaporation when the material is exposed to the air.
But if 1% of the glucose if converted to the acid, you will see the acid easily.
How exactly, will I 'see' (I assume measure) the acid? Don't forget the solution already has strong buffer salts, e.g. sodium phosphate.
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Well... how do you measure ("see") your glucose on the hplc? If you're using a mass spec detector, please stop injecting phosphate buffer into it.
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Well... how do you measure ("see") your glucose on the hplc? If you're using a mass spec detector, please stop injecting phosphate buffer into it.
I was told that phosphate buffer does not interfere with HPLC/RID glucose detection.
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Are you using a mass spec detector?
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Are you using a mass spec detector?
Nope, a Refractive Index detector is used.
Is it better to use Mass spec? I will have to ask a lab to do it.
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Is it better to use Mass spec?
Probably not in this case.
Do you have or can you get gluconic acid?
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Glad you're using refractive index detector (I wanted to check that you weren't trashing a mass spec with phosphate before I knew what exactly you were doing--not to leap to conclusions baselessly, but to make sure you weren't making a costly error--glad that is not the case!)
As Bored chemist says, if you have some gluconic acid, you can inject a sample that has the same buffer, mobile and stationary phases, and see if it has a similar retention time. You can also spike your glucose solution with it (maybe at a few concentrations) to see if its in there too.
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Is it better to use Mass spec?
Probably not in this case.
Do you have or can you get gluconic acid?
I don't think so. I think I will need to invest in the special gluconate columns, I suppose, thanks!
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I don't think so.
Why not?
Gluconic acid (or sodium gluconate) is a lot cheaper than a new column.