The effect of column length and column packing mesh size on the analysis of volatile fatty acids by gas chromatography using Chromosorb 101

Abstract

The effect of column length on resolution and retention time has been studied for the analysis of volatile fatty acids on Chromosorb 101. Using 80–100 mesch packing an optimum column length of 0.5 m was found. A comparison was then made between two 0.5-m columns, one packed with 80–100 mesh and the other with 100–120 mesh Chromosorb 101. The smaller mesh size resulted in considerably better resolution of isobutyric and n-butyric acids and gave over twice as many plates per foot as the larger mesh size under optimum operating conditions. However, rentention times were increased by about 40% (4.8 to 6.7 min for n-valeric acid). Several methods for isolating free volatile acids from aqueous solutions and plasma samples were tested and are discussed briefly.