Separation and Determination of Monoalkanolamides of Soybean Oil Fatty Acids by RP-HPLC of the Crude Reaction Product

Abstract

Abstract A reverse-phase HPLC technique, previously developed by us, was used to achieve satisfactory separation and determination of monoalkanolamides of the soybean oil fatty acids. Four reaction products, each containing a mixture of similar monoalkanolamides of the soybean fatty acids, were analyzed without pretreatment. Structurally, the four monoalkanolamides series differ in their alkanol moiety, having two or three carbon atoms in the alkanol chain which is substituted or unsubstituted. A series of N-methyl monoethanolamides was also prepared and HPLC analyzed. In each case, the separated components were isocratically eluted with a ternary solvent system of tetrahydrofuran-acetonitrile-water at pH 2.6 (37.5:37.5:25 v/v/v), followed by detection with a differential refractometer. In all cases, the elution order was in accordance with the length as well as with the degree of unsaturation of the hydrophobic chain of the monoalkanolamides. The sequence of the eluted components was elucidated by chroma...