Polar Phase Separates Steroids Better Neopentyl esters of diacids aid gas chromatography; rapid handling reduces decomposition Improved steroid separation follows the use of more polar stationary phases in gas chromatography, accord ing to Dr. S. R. Lmskv and Dr. R. A. Landowne of Yale University School of Medicine, New Haven, Conn. [Anal. Chem., 33, 818 (1961)]. Neopentyl esters of some diacids prove even bet ter than the silicone gum SE-30 (C&EN, July 25, 1960, page 4 0 ) . Decomposition of the stationary phase and the steroids was minimized
by rapid sample handling. A few. changes were noticed—dehydration of some hydroxyls, rearrangement of a few double bonds in polyenes, and some breaking up of oxygenated side chains. Making derivatives or these functions may solve this problem, Dr. Lipsky says. On the plus side, hydro carbon side chains appear to be stable, hydroxyls do not epimerize, nor do hydrogens at C-5. Some nreliminarv senarations based
Mixtures containing these C19 steroids...
on carbon number are necessary to prevent overlapping such as occurs be tween the C 2 i 0 2 and C 2 T O steroids. Effect of Groups. The Yale work ers observe several regularities about retention time and structure. With a double bond in rings A or B, time in creases; in C or D it decreases. Ring A or Β hydroxy compounds precede ketones; in C and D they follow. An oxygen function at C-17 has more re tention than a similar one at C-3. βHydroxy compounds follow the cor responding alpha ones. α-Hydrogen isomers are retained longer than the beta for C 2 i and C 2 7 steroids, less for the C 1 9 group. Methyl ethers or acetates show less retention than the parent hydroxy compounds.
Give these gas chromatograms
Androsterone Ο
x£ 0T\S^S
Epiandrosterone
Dihydrotestosterone
i ^ ^ V
Knit Epitestosterone O*
Testosterone
Q'^CTSS
Note:
46
Curves have been altered to give a common scale
C&EN
JUNE
5,
1961
elution time
(minutes)
