Look up the methods for 'volatile organic acids' like acetic, proprionic, butryic acids that can be found on websites for Waters, Agilent, Phenomenex, Restek... They use 'ion chromatography'. You might be able to use formic or citric acid buffer instead of phosphate. Experiment!

Dear Bruce,

first of all thanks for the reply!

I'm quite a neophyte with HPLC analysis.. so I'll try to use HPLC + 1% Formic acid as buffer (channel A) and acetonitrile (channel B) and try different isocratic/gradient combinations. Do you think that I'll damage the column with an high quote of aqueous mobile phase? I usually always wash the system with 100% methanol/acetonitrile at the end of the day. I'm a bit afraid to damage the instrument, i have had some problems with phosphate buffer and columns in the past.. :-(

Another question: I've already done some tests but I saw that the max abs is at 230-240nm (not 210 as aspected): could be that I'm analyzing the salt?

thanks!

Try adapting this method below. Note, it uses a specialty column and not C18 (reverse phase). Phosphate buffer is generally not a problem unless your ACN concentration raises >50%. Under acidic conditions Sodium Butyrate will ionize to Butyric Acid.

https://www.phenomenex.com/Application/Detail/5511?returnURL=/Application/Search&fsr=1