Steroid Hormones

The separation of some steroid hormones is another example of the use of silica gel as an interactive stationary phase the separation obtained is shown in figure 45.

Courtesy of Supelco Inc.

Figure 44 The Analysis of Acetaminophen Formulations

Courtesy of Supelco Inc.

(Supplied to Supelco by Dr. S. N. Rao and Prof. M. Okamato, Cornell University Medical College, New York)

Figure 45 The Separation of Steroid Hormones

The column was 25 cm long, 4.6 mm in diameter, and packed with silica gel particle (particle diameter 5 mm) which gave a maximum efficiency at the optimum velocity of 25,000 theoretical plates. The mobile phase consisted of 76% v/v n-hexane and 24% v/v 2-propyl alcohol at a flow-rate of 1.0 ml/min. The steroid hormones are mostly weakly polar, consequently, the separation on silica gel, will be based primarily on polarity. The silica, however, was heavily deactivated by a relatively high concentration of the moderator 2-propyl alcohol and, thus, the silica gel surface would be covered with isopropanol and the interacting surface would be virtually pure 2-propyl alcohol. Whether the interaction is by sorption or displacement is difficult to determine. It is likely that the early peaks interacted by sorption and the late peaks possibly by displacement.