Gas‐chromatographic determination of residual hexane in hexane‐extracted soybean flakes

Abstract A method was developed to determine residual hexane in hexane‐extracted soybean flakes by gasliquid chromatography (GLC). After residual hexane was extracted with pure isooctane, the quantity extracted was determined by GLC. Analyses were run on three different columns. Column efficiency was varied to obtain maximum speed and accuracy. An attenautor was used to amplify the low‐signal output of the extracted residual hexane. Accuracy of the method was established by analyzing soybean flakes containing 0.01舑7.5% added hexane. The lower limit of accuracy is approx 0.02%, and the time required for analysis is ca. one hr. Residual hexane present in other kinds of hexane‐extracted oilseed flakes might also be analyzed by this method. It is probable that extraction solvents other than hexane which are infinitely soluble in isooctane can also be determined by the method proposed.