Gas-liquid chromatographic determination of hexestrol residues in adipose tissue

A gas-liquid chromatographic (GLC) method is described for determining hexestrol residues in adipose tissue. The extraction and purification procedures were based on a published method for determining diethylstilbestrol. To increase precision and sensitivity, the sample was further cleaned up by silica gel column chromatography. The heptafluorobutyric (HFB) derivative of hexestrol was used for GLC analysis with HFB-docosanol as an internal standard. A variety of acetone-benzene mixtures were compared to determine the optimum ratio for hexestrol acylation. Acetone-benzene (90 + 10) or 100% acetone provided 16% higher GLC response than did a 50 + 50 mixture (P less than 0.001) and was selected for use in the acylation procedure. A system for evaporating excess reagents was also studied. Overall percent recovery reached 72 +/- 5. The method can be used to determine residual hexestrol at the 0.1 ppb level.