The polarity of the column stationary phase plays a critical
role in a successful separation for fatty acids. To improve peak
resolution, the polarity of the column stationary phase should
closely match the polarity of the fatty acids. Oleic acid and related
fatty acids are polar compounds in nature; therefore, four
types of columns having a similar polarity as the related fatty
acids were selected for column screening. A DB-FFAP column
(30 m 0.32 mm i.d., 0.25 mm film thickness, Agilent, Santa Clara,
USA) consists of a polyethylene glycol (PEG) bonded nitroterephthalic
acid phase. The phase is designed for the analysis of
volatile free fatty acids. In the experiment, DB-FFAP column easily
separated fifteen fatty acids within 20 min with most of the fatty
acid peaks exhibiting excellent peak symmetry. It also demonstrated
that the DB-FFAP column chemistry closely matched the
polarity of fatty acids being analyzed.