Structure-gas chromatographic electron capture sensitivity relationships of some substituted 17alpha-acetoxyprogesterones.
Structure-electron capture sensitivity relationships were established for underivatized 17alpha-acetoxyprogesterones. While progesterone was very insensitive, 17alpha-acetoxyprogesterone had a response of 4.8 X 10(2) C/mole. Methyl groups in the A or B ring of 17alpha-acetoxyprogesterone had no effect. A keto group at C-6 was 25 times more sensitive (1.2 X 10(4) C/mole). A double bond at C-6,7 enhanced the sensitivity sevenfold (3.5 X 10(3) C/mole), but double bonds at C-1,2 or C-9,11 had only slight effect. Substitution at C-16 was important. A methyl group at C-16 had two and three times the sensitivity in the 3-keto delta4 and 3-keto delta4,6 series (1.1 X 10(3) and 1.1 X 10(4) C/mole), respectively. A methylene group at C-16, in contrast showed a six-and twofold greater sensitivity over the C-16 methyl in the two series (7 X 10(3) and 2.2 X 10(4) C/mole), respectively. The most sensitive compound was 6-dehydro-6methyl-16-methylene-17alpha-acetoxyprogesterone (melengestrol acetate). Its sensitivity was 2.2 X 10(4) C/MOL, Comparable to the most sensitive halo esters of steroid alcohols reported in the literature. Its electron capture coefficient was 3-7.6X 10(10) 1/mole. The coef-icient was independent of the detector temperature, indicating low activation energy for electron absorpiton.
Properties of steroidal 3 enol heptafluorobutyrates.
Abstract Evidence is presented to show that esterification of steroid 4-en-3-ones by haptafluorobutyric anhydride in an equal volume of benzene produces near quantitative yields of 3 enol heptafluorobutyrate esters. The 3 enol and hydroxyl esters of several steroids have been prepared, their chemical stability studied, and their molar response to electron capture determined. 10–100 picogram amounts of the 3 enol heptafluorobutyrates can be determined by gas liquid chromatography with electron capture detection. The potential of the 3 enol esters for the ultramicrodetermination of biologically important steroid hormones is discussed.
Shape and surface texture of molten droplets deposited on cold surfaces
When a molten droplet impacts on a cold surface, the interaction between solidification and fluid dynamics can lead to different shapes and surface textures of deposited droplets. This article presents an experimental study on deposition of small droplets (39 μm diameter) of molten wax ink on solid surfaces. Our results show that both the final shape and the surface texture of deposited droplets are extremely sensitive to deposition conditions, which include initial temperature of droplets, type of substrate surface and distance between substrate and printhead. Different surface textures are observed and shown to depend on the thermal and flow histories of ink droplets during the process of impact. A test using crystalline wax reveals crystallization as one of the major factors in determining the final texture.