Gas chromatographic separation and determination of micro quantitative of C1-C7 Branched and straight-chain saturated fatty acids

A survey of thirteen different columns was carried out to find a suitable combination for the separation and determination of micro quantities of formic, acetic, propionic, isobutyric, n-butyric, isovaleric, n-valeric, isocaproic, n-caproic and heptanoic acid. A 4 ft. x 1 4 in. O.D. stainless steel column with 3.125% PEGA on acid-washed Chromosorb W ( 60 80 mesh) gave the best results in separation and sensitivity under isothermal and temperature-programming conditions. Using the dual hydrogen flame ionization detector on a Beckman GC-M, a helium flow rate of 100 ml/min and temperature programming between 100-150° at a rate of 5°/min, all acids could be separated and 0.5 μg of acid could be estimated. Isothermally with the thermoconductivity cell, 10 μg was the lowest amount detectable, for all investigated acids