Chromatography Forum

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Being very general, if acrylic acid elutes at the solvent front, you don't have a workable method, but reducing the %ACN should give you longer retention.

As for conversion from C18 to C8, if both packings are from the same "family" (i.e., same vendor and same underlying silica), then the C8 will be less retentive (i.e, you will have to reduce %ACN to get comparable retention). If they are from differeng families, then all bets are off. In general, C8 columns are less retentive than C18, but there is tremendous amount of overlap in the two distributions.

After consulting with some people from Waters, I think I need to go to a lower pH overall. A few methods they pulled use a weak phosphoric acid solution. (0.1%). I'm going to play around with this and see what happens. I have a method for MeOH:H3PO4 and one with ACN:THF:H3PO4.

Thank you Tom.

We have a customer who is currently validating quantitation of acrylic acid in low molecular weight polymer. They are using our Primesep D and Primesep SB column. Acrylic acid is retained by combination of weak reverse phase and anion-exchange mechanisms.

I did some work on analyzing acrylic acid and its oligomers using Acclaim Organic Acids column (Dionex). This linker leads you to the c-grams: http://www.dionex.com/en-us/flash/fullflash24960.html
This method is pretty straight-forward and is being used as one of our manufacturing QC tests. The MSA can be replaced by phosphoric acid without any problem. I would recommend the use of guard column for your application though to be on the safe side.

I did some work on analyzing acrylic acid and its oligomers using Acclaim Organic Acids column (Dionex). This linker leads you to the c-grams: http://www.dionex.com/en-us/flash/fullflash24960.html
This method is pretty straight-forward and is being used as one of our manufacturing QC tests. The MSA can be replaced by phosphoric acid without any problem. I would recommend the use of guard column for your application though to be on the safe side.

Thank you XL, I completely forgot about any Oligomers of acrylic acid. Do you happen to know how much this column goes for? We are trying to keep our spending to a minimum and work with the columns we have. Would we be able to do this on an alternative column?

Hi Tim,
There could be other columns that can do the same thing, but try to stay away high-density C18 and C8 because they tend to de-wet under high aqueous conditions.
I recommend Acclaim Organic Acid column because of its compatibility with 100% aqueous mobile phase and good separation power for organic acids by RP. The column costs between $500 to $600 (I don't know exact number since I am working in R&D). I hope it is not too expensive for you. Please let me know if you need more information.

I figured I would give an update on this topic. I was finally able to convince my boss that the method we had was crap (of course i didn't come right out and say that).

I went to an acidic mobile phase (0.1% phosphoric acid), increased the flow rate to suit the column. The column was a Waters atlantis C18 250 x 4.6 mm, and ran isocraticly for 20 min. Acrylic acid elutes at about 17.5 min. Not incredibly fast, but GREATLY improved.

UV detection was set at 210nm.

I am asked to quantify acryloyl chloride and acrylic acid in a sample. I think I should use normal phase LC with dry solvents. Has anyone have some suggestion where to start?
Many Thanks

Your acryloyl chloride will react with residual silanols, you need to quench sample with ammonia, for example and analyze as amide, or you can use benzylamine for quenching. Alternatively you can hydrolize it and quantitate HCl and acetic acid

Tank you for your suggestion