A 'k.xvey Of ihirteen' different columns was carried out' to find a suitable' combination for the separation' and determination of micro quantities of formic, acetic, propionic, isobutyric, gz-butyric, isovaleric, N-valeric, isocaproic, ?z-caproic and heptanoic acid. A 4 ft. x z/4 in. O.D. stainless steel column with 3.225 OL 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 roe ml/min and temperature programming between IOO--150~ at a rate of 5 "/min, all 'acids could be separated and 0.5 pg of each acid with the exception of formic acid was standardizable, 0.1 ,ug of acid could be estimated. Isothermally with the thermoconductivity cell, ,xo,pg was the lowest amount detectable, for all investigated acids, * .
In this report, a method of high sensitivity for the determination of the straightand branched-chain saturated C,-C, fatty acids is reported, MATERJALS AND' METHODS . .
Gas chzrornatogra#h~
For isothermal investigations a Beckman GC-2 was used with the same arrangements as described for alcohol determinations119 12. 'J.. C/rvcy~talog,, ,3g (rgGg) 398-406 GC OF ULCRO QUANTLTIES OP c,-c, SATURATED FATTY ACIDS 399 'J. Cl&m&&., '$"(rgGg).398-406