Analysis of volatile fatty acids in rumen fluid by proton NMR spectroscopy

A study was conducted to quantify the volatile fatty acid (VFA) concentrati ons in aqueous and rumen fluid samples using a standard additions based qua ntitative proton nuclear magnetic resonance (NMR) spectroscopic method. Sta ndard plots for acetic, propionic and butyric acids were all found to be li near (R-2 > 0.99). Results obtained by NMR were compared with those obtaine d using the conventional gas chromatographic method. No significant differe nces were found between the means and precisions of the two techniques (P < 0.05). The method is well-suited for the routine quantification of these a cids, requires no sample pretreatment and is more rapid than gas chromatogr aphy.