Chromatography steroid

Gas Chromatography - Steroids possessing the C-17 dihydroxyacetone side chain usually undergo molecular alteration after application to GLC columns to yield as a major product the corresponding 17-ketosteroid. 

Touchstone JC (1986) Handbook of Chromatography, Steroids. Boca Raton, FL CRC Press. 

Measurement of Low Levels of Estrone and 17B-Estradiol in Urine, Employing Ion-Exchange, Thin-Layer and Gas-Liquid Chromatography Steroids 14(5) 553-573 (1969) CA 72 18799p... 

Determination of Urinary Testosterone Using Thin-Layer Chromatography and Gas Chromatography Steroids 3(5) 559-568 (1964) CA 61 13590e... 

Determination of Urinary Tetrahydro-cortisone, Tetrahydrocortisol, and 3a-Allotetrahydrocortisol by Gas Chromatography Steroids 6(5) 583-596 (1965) CA 64 2353b... 

Capillary Gas Chromatography. Steroid esters are thermally stable. They can be analyzed easily by CGC. Figure 60 shows the analysis of the sample with cold on-column injection. The plate number for this conventional CGC column operated at 130°C was 85000 plates analysis time was 22 min. The quantitative results (response fac-... 

Chromatography Steroids (54). The methyloxime-trimethylsilyl ether derivative has become the method of choice for derivatizing steroids. The success of this derivatization procedure is due to the ease by which both carbonyl and hydroxyl groups can be protected. 

H. Lamparczyk, in Handbook of Chromatography Steroids, J. Sherma, ed., CRC Press, Boca Raton, FL, 1992. 

Paper Chromatography.—Steroidal D-glucuronides have been separated by reversed-phase partition chromatography on paper impregnated with organic... 

This publication provides several examples of the use of solid-phase extractions for separating analytes from their matrices. Some of the examples included are caffeine from coffee, polyaromatic hydrocarbons from water, parabens from cosmetics, chlorinated pesticides from water, and steroids from hydrocortisone creams. Extracted analytes maybe determined quantitatively by gas (GC) or liquid chromatography (LG). 

The diphenylmaleimide is prepared from the anhydride, 33-87 % yield, and cleaved by hydrazinolysis, 65-75% yield. It is stable to acid (HBr, AcOH, 48 h) and to mercuric cyanide. It is colored and easily located during chromatography, and has been prepared to protect steroidal amines and amino sugars. " ... 

Toluene is a useful co-solvent in metal-ammonia reductions as first reported by Chapman and his colleagues. The author has found that a toluene-tetrahydrofuran-ammonia mixture (1 1 2) is a particularly useful medium for various metal-ammonia reductions. Procedure 8a (section V) describes the reduction of 17-ethyl-19-nortestosterone in such a system. Ethylene dibromide is used to quench excess lithium. Trituration of the total crude reduction product with methanol affords an 85% yield of 4,5a-dihydro-17-ethyl-19-nortestosterone, mp 207-213° (after sintering at 198°), reported mp 212-213°. For the same reduction using Procedure 5 (section V), Bowers et al obtained a 60% yield of crude product, mp, 196-199°, after column chromatography of the total reduction product. A similar reduction of 17-ethynyl-19-nortestosterone is described in Procedure 8b (section V). The steroid concentration in the toluene-tetrahydrofuran-ammonia system is 0.05 M whereas in the ether-dioxane-ammonia system it is 0.029 M. 

As a general procedure, a mixture of the steroidal ketone (50 mg) and lithium aluminum deuteride (20 mg) in dry ether (5 ml, freshly distilled from lithium aluminum hydride) is heated under reflux until the reduction is complete according to thin layer chromatography test. The excess deuteride is then decomposed by the careful addition of a few drops of water and the reaction mixture is worked up by the usual procedure. For hindered ketones or esters the use of other solvents, such as tetrahydrofuran or dioxane, may be preferable to allow higher reaction temperatures. 

A -Steroids react sluggishly with nitrosyl fluoride to yield after alumina chromatography the nitro-olefin (44) (14 %), and 0.7 % of the 2a-fluoro ketone (45), the former probably arising by alumina-catalyzed dehydrofiuorination of an intermediate 2-fluoro-3-nitro adduct. 

It is noteworthy that treatment of the 9(ll)-dehydro steroid (50) with nitrosyl fluoride in ethyl acetate at 50° affords after chromatography a 20% yield of the A hi2-ketone. ... 

In gas chromatography/mass spectrometry (GC/MS), the effluent from a gas chromatograph is passed into a mass spectrometer and a mass spectrum is taken every few milliseconds. Thus gas chromatography is used to separate a mixture, and mass spectrometry used to analyze it. GC/MS is a very powerful analytical technique. One of its more visible applications involves the testing of athletes for steroids, stimulants, and other performance-enhancing drugs. These drugs are converted in the body to derivatives called metabolites, which are then excreted in the... 

Electropherograms of a urine sample (8 ml) spiked with non-steroidal anti-inflammatory drugs (10 p-g/ml each) after direct CE analysis (b) and at-line SPE-CE (c). Peak identification is as follows I, ibuprofen N, naproxen K, ketoprofen P, flurbiprofen. Reprinted from Journal of Chromatography, 6 719, J. R. Veraait et al., At-line solid-phase exti action for capillary electrophoresis application to negatively charged solutes, pp. 199-208, copyright 1998, with permission from Elsevier Science. 

Reverse phase chromatography is finding increasing use in modern LC. For example, steroids (42) and fat soluble vitamins (43) are appropriately separated by this mode. Reverse phase with a chemically bonded stationary phase is popular because mobile phase conditions can be quickly found which produce reasonable retention. (In reverse phase LC the mobile phase is typically a water-organic solvent mixture.) Rapid solvent changeover also allows easy operation in gradient elution. Many examples of reverse phase separations can be found in the literature of the various instrument companies. 

Hanselman TA, Graetz DA, Wilkie AC, Szabo NJ, Diaz CS (2006) Determination of steroidal estrogens in flushed dairy manure wastewater by gas chromatography-mass spectrometry. J Environ Qual 35 695-700... 

Combalbert S, Pype ML, Bemet N, Hemandez-Raquet G (2010) Enhanced methods for conditioning, storage, and extraction of liquid and solid samples of manure for determination of steroid hormones by solid-phase extraction and gas chromatography-mass spectrometry. Anal Bioanal Chem 398 973-984... 

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