Steroidal isomers with uniform mass spectra of their per-TMS derivatives: Synthesis of 17-hydroxyandrostan-3-ones, androst-1-, and -4-ene-3,17-diols

Derivatization and fragmentation pattern analysis of natural and synthetic steroids, as their trimethylsilyl (oxime) ether derivatives by gas chromatography mass spectrometry: Analysis of dissolved steroids in wastewater samples

“…2a, compounds: 6,8,9,12,13,14) including the 3, 17 diketosteroids (Fig. 2a, compounds 11, 16), in comparison to that of the 17-ketosteroids { (Fig.…”

“…-ketosteroids have been evaluated partly from linear responses (Table 4, compounds 1, 3,4,8,9,12), partly from calibration curves (11,13,14,16,18). In both cases reproducibilities characterized with their relative standard deviation percentages were acceptable.…”

“…The relevancy of the topic can be characterized by the fact that steroid profiling proved to be of primary importance in the diagnosis of clinical disorders [4,11,[13][14][15][16][17][18][19][20][21][22]26,29,50,53,54,64], in the recognition of drug abuses in sports doping control [8,12], in food analysis [2,3,45] and most importantly in the pollutant analysis of environmental water samples (trimethylsilyl)trifluoro-acetamide (BSTFA) , N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide (MTBSTFA) [46,47], and trimethylsilylimidazole(s) (TMSI) [48][49][50]. Acylations were performed with pentafluorobenzoyl chloride [51][52][53] or with heptafluorobutyric anhydride [54,55].…”

“…Authors of this paper are convinced that (1) unsatisfactory analytical attention was paid to the distinction, consequently, to the simultaneous identification and quantification of the keto, the keto and hydroxyl and the only hydroxyl group(s) containing steroids, from a single chromatographic run, in shortage of exhaustive mass fragmentation studies, (2) in several proposals the keto groups' derivatizations are simply neglected [5][6][7]10,13,16,17], (3) in others, by means of reductive silylation {MSTFA/NH 4 J/ dithiothreitol (DTE) ≈ 500-1000/4/2 (v/v/v)}, keto groups were transformed to the corresponding hydroxyl groups containing species: consequently, for sake of distinction, two derivatizations (a reductive and a non reductive one) would be needed [1][2][3][4]6,8,11,12,14,15,[18][19][20][21]60], (4) the advantage of the analysis of the methyloxime trimethylsilyl derivatives of steroids was, unfortunately, used in few cases, and without basic studies, only [32,[48][49][50]64]. This protocol was applied in the analysis of faecal sterols from catchment waters [32], selected steroids from wastewaters [48], to identify dehydroepiandrosterone and its 7-oxygenated metabolites in human serum [49], to quantify urinary steroids, selectively [50] and to define steroid disorder metabolomes [64].…”

Determination of Adrenosterone and its Metabolites in Human Urine by LC/APCI/MS and GC/MS

“…The dried residue was dissolved in 50 µL of MSTFA/NH 4 I/ DTE (500:4:2, w/w/w) and the solutions was heated for 30 min at 70 o C. Two µL was injected into the GC/MS. 22,23 Method validation. For a calibration curve of adrenosterone, the proper amount of standard and internal standard to 1, 2, 5, 10 and 20 ng mL -1 were fortified into the 3 mL blank urine and used for GC/MSD after trimethylsilylation.…”