Download PDF by Kristen B. Eik-Nes, Evan Charles Horning: Gas Phase Chromatography of Steroids

By Kristen B. Eik-Nes, Evan Charles Horning

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Conditions: 12 ft 10fo OV-1 (on 100-120 mesh Gas Chrom P) column; temperature programmed at 1°/min from 200°; injector, 250°; detector, 300°; nitrogen, 26 psi; flame detector. The geometric (syn/anti) isomers are not sufficiently different in molecular shape to permit a separation, although the shape of the testosterone peak indicates that two compounds are present. The epitestosterone peak has an approximately theoretical shape, but two isomers are present. This is shown in Fig. 9 28 Gas Phase Analytical Methods for the Study of Steroid Hormones The chromatographic relationships between androsterone and pregnanediol, both as free steroids and as TMSi derivatives, are MO-TMSi 1% OV-17 TP 1"/min Test Epitest 20 30 Time(minl Fig.

4; the separation of Sa- and 5/lcholestane occurs with OV-17 as well as with OV-1. The number, nature and stereochemical arrangement of the functional groups is an important matter as well, and as the polarity of the phase increases the functional group retention effects also increase in magnitude. Phase QF-1 has perhaps the greatest degree of stereochemical specificity of all phases now in use, but positional isomers and epimers may also be distinguished with polyester phases. Hydroxyl and keto groups lead to major increases in retention time; the acetyl group also has polar properties, while ethers are relatively non-polar.

7 demonstrates the separation of testosterone and epitestosterone, both as free steroids and as TMSi derivatives, with an OV-17 phase. Epimer separation of the free steroids occurs with a selective phase, but not with a non-selective phase. The derivatives, however, are separated with both types of phases, and the separation is based upon a difference in molecular shape. Fig. 8 and 9 show the separation pattern observed for the MOTMSi derivatives of testosterone and epitestosterone with OV-1 and OV-17 phases.

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