In order to measure Vitamin C, we use metaphosphoric acid (HPO3) to eliminate copper and make the ascorbic acid stable. However, for HPO3 lack, we are looking for another product which have the same proprieties than HPO3.
Do you have any suggestions..
Thank you in advance
You can use 50-60% (NaPO3)n basis.A colorless glassy polymeric phosphoric acid, (HPO3)n, that is highly deliquescent and forms phosphoric acid upon addition of water, used as a dehydrating agent, phosphorylating agent, and in dental cements. YOu can also use polyphosphoric acid - a series of oxyacids of phosphorus.
Dear Mr Kebsi, I don't know if this can help you, but we determined ascorbic acid using UV spectrophotometry (Use of column with modified silica for interfering retention in a FIA spectrophotometric method for direct determination of vitamin C in medicine). We also developed an ion selective electrode (Potentiometric Sensor for L-Ascorbic Acid Based on EVA Membrane Doped with Copper(II)). To eliminate interference of metal ions you can use EDTA or then at pH 4.7 to precipitate copper (II) using ammonium thiocyanate. Potentiometric titration is an alternative, too. See the paper: Riyazuddin P, Nazer, MMAK. Potentiometric determination of ascorbic acid in pharmaceutical preparations using a copper based mercury film electrode. J Pharm Biomed Anal 1997; 16: 545–551. My articles you can download in my profile. I hope that this helps you. Kind regards.
Dear Mr Kebsi, one correction, ammonium thiocyanate removes copper (I) ions and not copper (II) ions. Good lucky.
Hello, for stabilization of ascorbic acid you can also use 0.1 M acetic acid (it is simple way). I have paper that shows that you could also for stabilization of ascorbic acid use gylcine and oxalate. Send me email to klepolejlavgmail.com if you need that kind of paper and I will send you, but easiest way is to use acetic acid. Use EDTA to eliminate metal ions. Good luck.
Thank you for your message. I'm afraid, i i've been failing for 1 week sending you an email. This is mine. [email protected]
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