Analysis of Commercially Available Fatty Acids

THE introduction of polyethylene glycol adipate as a stationary phase in gas/liquid chromatography has made possible the separation and identification of the long-chain fatty acids present in such materials as montan wax 1 . This method has also proved useful in assessing the purity of commercially available fatty acids required for work with Langmuir monolayers. The acids were esterified with methanol and sulphuric acid. The esters were recrystallized from methanol, and were analysed chromatographically, using an 18-in. column (10 per cent polyethylene glycol + 1 per cent phosphoric acid on ‘Celite’) at a temperature of 210° C., with a hydrogen–nitrogen gas mixture (75 : 25) flowing at 25 ml./min. A flame-ionization detector was used. Results of the analysis of a number of commercially available acids are summarized in Table 1.