Porous Polymer Bead Packings and Formic Acid Vapor in the GLC of Volatile Free Fatty Acids

Abstract

Three types of porous polymer beads (Chromosorb 101, Porapak-QS, Porapak-N) packed in stainless steel columns were evaluated for GLC of the volatile free fatty acids under loads (ca 10⁻⁸ moles) often encountered with flame ionization detection of analytical samples. The addition of formic acid vapor to the carrier gas suppressed peak tailing and other absorption effects to give effective quantitation, but did not seriously modify retention times or appear to effect column life. Cyclohexanone was used as an internal standard. Isobutyric acid showed a greater response than butyric acid, but isovaleric acid had the same response as valeric acid. chromosorb 101 gave superior resolution of corresponding iso and normal acids.