3/10/22

Dear Lakroun,

Bio-Rad laboratories makes a fermentation monitoring column (Fermentation Monitoring Column #1250115.150 x 7.8 mm, prepacked HPLC organic acid and alcohol column, hydrogen form, 9 μm particle size, 8% cross linkage, pH range 1–3 See the link below.) I've used it for monitoring corn fermentations using yeast and for measuring ethanol and organic acids in wine. I think the column is available in lengths of 150 and 300 mm.

For a mobile phase, we use 5 mM H2SO4, and run the HPLC @ 65C at a flow rate of 0.65 mL/min. Detection is via refractive index (RID). 35 min of run time for each sample. The column resolves glycerin, ethanol, glucose, fructose and the following organic acids: Acetic, malic, succinic, lactic, citric and tartaric. We've never tried to separate propionate and butyrate, but it might work for you. Don't forget that will also need a guard column.

You can go on Bio-Rad's website and find more information about this.

https://www.bio-rad.com/en-us/sku/1250115-fermentation-monitoring-column?ID=1250115

I hope this information helps you.

Bill Colonna Iowa State University, Ames, Iowa, USA [email protected]

3/10/22

Dear Lakroun,

I forgot to mention about standards. The stock solution for each standard is as follows:

Ethanol: 100 g/L

Glucose & Fructose: 50 g/L each

Glycerol: 20 g/L

Tartaric, citric, malic & succinic acids: 10 g/L each

Lactic and acetic acid: 5 g/L each

Solvent for all standards: DI-water

From each of these, we made five 2-fold dilutions. Final dilution = 1:16 of original.

The final standard dilutions contained all 10 solutes.

Good luck!

Bill Colonna

Thanks a lot, Mr. Colonna. I am very appreciated.