Trace Analysis of Estradiol in Animal Chow by Electron-Capture Gas Chromatography

Abstract
A gas chromatographic method is described for trace analysis of the natural steroidal hormone estradiol in animal chow at levels as low as 3 ppb. Salient elements of the method include extraction of the estradiol with methanol, an initial clean-up on a column of Sephadex LH-20, liquid-liquid partitioning at pH 14 and 10.2, additional cleanup on a silica gel column, conversion of the estradiol to the pentafluoropropionyl (PFP) derivative and analysis by electron-capture gas chromatography on a column of OV-25. Samples containing less than 100 ppb of estradiol are subjected to further cleanup on silica gel after derivatization and prior to analysis.