A new oxidation method for the determination of saturated fatty acids

Summary A method for the quantitative determination of the saturated acids in fats has been developed. This method is based upon the non‐disruptive oxidation of the unsaturated acids by performie acid, extraction of the oxidized mixture with petroleum ether and, finally, chromatographie purification of the saturated acids. The final residue contains a small quantity of non‐acid material, usually 0.1 to 0.7%, based on the total mixed fatty acids. The unsaturation of these saturated acids is equivalent to about 0.1%, as oleic acid, so that a total absolute correction of about 0.4% must be applied. The method is fairly simple and rapid, requiring about six hours for one determination and can be applied to a wide variety of fats. The method has been tested with known mixtures of pure saturated and unsaturated acids, with results varying up to 0.6% from the calculated values. Recovery of added saturated acids to olive oil fatty acids has also been satisfactory. Application of the method to the common fats shows good reproducibility, with results that compare favorably with the best accepted values. Fats containing distinctive acids, such as isooleic, eleaostearic, chaulmoogric, and rieinoleic acid, presented no analytical difficulties. However celery seed oil (petroselinic acid) contains interfering nonfatty material so that the final residue must be further purified. The method can also be used with fats containing lauric, capric, and small quantities of caprylic acids but is not satisfactory when appreciable quantities of water‐soluble saturated acids are present.