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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: denisa174 on April 23, 2021, 02:28:11 AM

Title: AAS Si standard
Post by: denisa174 on April 23, 2021, 02:28:11 AM
Hello,

I have got a silicon standard solution for AAS is in 2% NaOH. How should I prepare the 2% NaOH? Does that easily mean 2 g in 100 ml in measuring flask? There is not any indication of v/v or w/w or w/v

Thank you very much
Title: Re: AAS Si standard
Post by: chenbeier on April 23, 2021, 02:53:09 AM
I think it must not very accurate 2 g in 100 ml should be fine.
Title: Re: AAS Si standard
Post by: Borek on April 23, 2021, 03:03:58 AM
I have got a silicon standard solution for AAS

So you are saying you have the ready solution? If so, why do you ask how it should be prepared? Somehow I think you didn't wrote what you wanted to, can you elaborate?

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a silicon standard solution for AAS is in 2% NaOH. How should I prepare the 2% NaOH? There is not any indication of v/v or w/w or w/v

Sounds like 2% NaOH is just a supporting solution, so its concentration doesn't have to to be too exact, even few percent error won't matter. Difference between 2% w/w and w/v are completely negligible in such case.

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Does that easily mean 2 g in 100 ml in measuring flask?

Good analytical practice is to not use measuring flasks for preparation of such solutions - NaOH is corrosive to the glass. I would prepare the solution of NaOH in a beaker.
Title: Re: AAS Si standard
Post by: denisa174 on April 23, 2021, 09:06:00 AM
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So you are saying you have the ready solution? If so, why do you ask how it should be prepared? Somehow I think you didn't wrote what you wanted to, can you elaborate?

I have got the standard, but for AAS analysis I need to have the same solution for calibration and for dilution of samples.

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Sounds like 2% NaOH is just a supporting solution, so its concentration doesn't have to to be too exact, even few percent error won't matter. Difference between 2% w/w and w/v are completely negligible in such case.

Ok, thanks

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NaOH is corrosive to the glass. I would prepare the solution of NaOH in a beaker.

That is good point, thanks