Determination of volatile fatty acids in digestate by solvent extraction with dimethyl carbonate and gas chromatography-mass spectrometry.

Volatile fatty acids (VFAs) are among the most important parameters in process monitoring of anaerobic digestion plants for biogas production. The concentration of single VFA species is typically determined by direct injection of the acidified aqueous phase of digestate samples into GC-FID. Analysis of dimethyl carbonate extracts was investigated as an alternative method consisting of a simple and rapid in-vial procedure of acidification and solvent extraction of the sample, followed by centrifugation and GC-MS analysis.