Chromatography Forum

Hello.

Im trying to find a method for the analysis of organic acids in honey using hplc with uv detector. At this stage my problem is to find a correct spe extraction method. I tried SPE SAX/NH2 using H2SO4 at pH 1,2 to elute the organic acids from the colune and it was ok, however there are some oustider peaks that I think are due to the low pH across the SPE. Would it be possible with C18 SPE colunns? How should i conditioning the colunn without the retention of sugars?
All help is welcome. Thanks

Reversed phase SPE won't work for discriminating between sugars and formic or oxalic acid; the k' < 0.3 is just too small.

Don't give up on SAX. Try other conditioning treatments. Try other vendors.

If you think that the peaks come from the SPE, then let me recommend a polymer-based SPE such as the Oasis MAX. This material may have some other advantages too, since you can combine hydrophobic interaction with ion-exchange. Specific protocols have been worked out for many sample preparation problems, as well as many generic protocols. You can find them on the Waters website.

The determination of formate and oxalate should be possible on a Ion Chromatography column like Metrosep A Supp 5 – 150 under standard conditions with conductivity detection.

In an old application standard anions in honey have been determined. From that chromatogram we can see that there is no interference in the retention time window of the tw ions of interest.

Hi,
Ion exclusion chromatography with strong cation exchange column
(-SO3H) hydrogn base with stryrene divinyl benzene polymeric column, refractive index or uv detector, 0.1% H3PO4 mobile phase and 60 degree tempetature may work for u. Even u may not need to do sample preperation.

We've done formic acid using dilute H2SO4 mobile phase on an ion-exclusion column with conductivity detection. We have never investigated oxalic acid.