HPLC about seperating organic acids?
Answer:
A reverse phase column (usually C-18, especially a Cogent Bidentate substrate) is preferred. Use a particle size of 100 microns or less and a column length of 50 mm or more for good resolution.
There are several C-18 substrates which have been altered just for the rapid separation of organic acids.
A phosphate buffered aqueous solution (slightly acidic) or a buffer/CH3CN mobile phase will work well if you use 254 nm detector. The acetonitrile concentration can be less than 50% and you can get acceptable resolution.
Water's Sep-packs have been used with great success. A guard column is also a good idea.
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reverse phase, 60 or 100 micro particles, just plain silica.
the best eluent would be something along the lines MeOH: phosphate buffer (darn there was a site allowing you to calculate the amounts of acid and NaH2PO4 needed for pH 4.5, but can´t find it now) 4:1 or 3:1, or MeCN: same buffer.
oxalic acid comes at about 2.5-3 mins, separates well with small trailing from acetaldehyde and acetic acid. the aromatic one should come somewhat later.
EDIT: you might wanna take a peek at those two
http://www.grom.de/catalogue/03.pdf...
and
http://www.sge.com/uploads/ww/ve/wwvewjz...
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