Merck

Microwave-assisted derivatization: application to steroid profiling by gas chromatography/mass spectrometry.

Journal of chromatography. B, Analytical technologies in the biomedical and life sciences (2014-05-02)
Gregori Casals, Josep Marcos, Oscar J Pozo, José Alcaraz, María Jesús Martínez de Osaba, Wladimiro Jiménez
RESUMEN

Gas chromatography-mass spectrometry (GC-MS) remains as the gold-standard technique for the study of the steroid metabolome. A main limitation is the need of performing a derivatization step since incubation with strong silylations agents for long periods of time (usually 16 h) is required for the derivatization of hindered hydroxyls present in some steroids of interest. In the present work, a rapid, simple and reproducible microwave-assisted derivatization method was developed. In the method, 36 steroids already treated with methoxyamine (2% in pyridine) were silylated with 50 μl of N-trimethylsilylimidazole by using microwave irradiation, and the formed methyloxime-trimethylsilyl derivatives were analyzed by GC-MS. Microwave power and derivatization time silylation conditions were optimized being the optimum conditions 600 W and 3 min respectively. In order to evaluate the usefulness of this technique, the urine steroid profiles for 20 healthy individuals were analyzed. The results of a comparison of microwave irradiation with the classical heating protocol showed similar derivatization yields, thus suggesting that microwave-assisted silylation is a valid tool for the rapid steroid metabolome study.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Acetic acid, glacial, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8%
Sigma-Aldrich
Acetic acid, glacial, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, 99.8-100.5%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Methanol, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8% (GC)
Sigma-Aldrich
Methanol, puriss., meets analytical specification of Ph Eur, ≥99.7% (GC)
Sigma-Aldrich
Methanol, BioReagent, ≥99.93%
Sigma-Aldrich
Acetic acid solution, suitable for HPLC
Sigma-Aldrich
Sodium acetate, puriss. p.a., ACS reagent, reag. Ph. Eur., anhydrous
Sigma-Aldrich
Acetic acid, glacial, ≥99.99% trace metals basis
Sigma-Aldrich
Sodium acetate, ACS reagent, ≥99.0%
Supelco
Stigmasterol, certified reference material, 10 mg/mL in chloroform
Sigma-Aldrich
Acetic acid-12C2, 99.9 atom % 12C
Sigma-Aldrich
Cortisone, ≥98%
Sigma-Aldrich
Stigmasterol, ~95%
Sigma-Aldrich
Sodium acetate, anhydrous, for molecular biology, ≥99%
Sigma-Aldrich
Sodium acetate, meets USP testing specifications, anhydrous
Sigma-Aldrich
Sodium acetate, BioXtra, ≥99.0%
Sigma-Aldrich
Sodium acetate, powder, BioReagent, suitable for electrophoresis, suitable for cell culture, suitable for insect cell culture, ≥99%
Sigma-Aldrich
1-(Trimethylsilyl)imidazole, 96%
Supelco
1-(Trimethylsilyl)imidazole, for GC derivatization, LiChropur
Sigma-Aldrich
Methoxylamine hydrochloride solution, 25-30 wt. % in H2O
Sigma-Aldrich
Cyclohexane, anhydrous, 99.5%
Sigma-Aldrich
Acetic acid, natural, ≥99.5%, FG
Sigma-Aldrich
Acetic acid, ≥99.5%, FCC, FG
Sigma-Aldrich
Sodium Acetate Anhydrous, >99%, FCC, FG
Sigma-Aldrich
Methoxyamine hydrochloride, 98%
Sigma-Aldrich
Methanol, anhydrous, 99.8%
Supelco
Cyclohexane, analytical standard
Sigma-Aldrich
1-(Trimethylsilyl)imidazole, ≥98.0%
Sigma-Aldrich
Acetic acid, for luminescence, BioUltra, ≥99.5% (GC)