Volatile fatty acids analysis from pig slurry using high-performance liquid chromatography

A simple and sensitive liquid chromatography method designed to determine the volatile fatty acids (VFA) content in pig slurry sample is proposed. The acids are isolated with a cation exchange column for carbohydrates using an isocratic phosphate eluant coupled with an ultraviolet detector in series. Centrifuged and filtered samples can be injected directly into the liquid chromatographic system. The accuracy of this new liquid-chromatographic chain using spiked solutions ranging between 20 and 5000 mg/L of VFA standard solution varied from 87 to 124%. The precision of the new procedure, expressed as variability, was between 9.2 and 0.6% for a spike solution concentration of 20 and 5000 mg/L, respectively.