Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17alpha-ethinylestradiol by gas chromatography-mass spectrometry.
J Chromatogr A. 2006 Mar 03; 1108(1):121-8.JC

Abstract

This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17alpha-ethinylestradiol (EE2) and estrone (E1) using gas chromatography-mass spectrometry (GC-MS). This follows a re-assessment of some of the popular silylation procedures using N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N-O-bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA+1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC-MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions.

Authors+Show Affiliations

Shareef A

Colloid and Environmental Chemistry Laboratory, La Trobe University, Bendigo, Vic. 3552, Australia. a-shareef@dhinet.net.mv

Angove MJ

No affiliation info available

Wells JD

No affiliation info available

MeSH

AcetamidesEstroneEthinyl EstradiolFluoroacetatesGas Chromatography-Mass SpectrometryOrganosilicon CompoundsTrifluoroacetic AcidTrimethylsilyl Compounds

Pub Type(s)

Journal Article

Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16445920

Citation

Shareef, Ali, et al. "Optimization of Silylation Using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the Determination of the Estrogens Estrone and 17alpha-ethinylestradiol By Gas Chromatography-mass Spectrometry." Journal of Chromatography. A, vol. 1108, no. 1, 2006, pp. 121-8.

Shareef A, Angove MJ, Wells JD. Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17alpha-ethinylestradiol by gas chromatography-mass spectrometry. J Chromatogr A. 2006;1108(1):121-8.

Shareef, A., Angove, M. J., & Wells, J. D. (2006). Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17alpha-ethinylestradiol by gas chromatography-mass spectrometry. Journal of Chromatography. A, 1108(1), 121-8.

Shareef A, Angove MJ, Wells JD. Optimization of Silylation Using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the Determination of the Estrogens Estrone and 17alpha-ethinylestradiol By Gas Chromatography-mass Spectrometry. J Chromatogr A. 2006 Mar 3;1108(1):121-8. PubMed PMID: 16445920.

* Article titles in AMA citation format should be in sentence-case

TY - JOUR T1 - Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis-(trimethylsilyl)-trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of the estrogens estrone and 17alpha-ethinylestradiol by gas chromatography-mass spectrometry. AU - Shareef,Ali, AU - Angove,Michael J, AU - Wells,John D, Y1 - 2006/01/30/ PY - 2005/09/18/received PY - 2005/12/23/revised PY - 2005/12/27/accepted PY - 2006/2/1/pubmed PY - 2006/4/18/medline PY - 2006/2/1/entrez SP - 121 EP - 8 JF - Journal of chromatography. A JO - J Chromatogr A VL - 1108 IS - 1 N2 - This paper reports an improved silylation procedure for simultaneous determination of the steroid hormones 17alpha-ethinylestradiol (EE2) and estrone (E1) using gas chromatography-mass spectrometry (GC-MS). This follows a re-assessment of some of the popular silylation procedures using N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N-O-bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA), which lead to the formation of trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBS) derivatives. Silylation of EE2 using MSTFA or BSTFA+1% TMCS in ethyl acetate, acetonitrile and dichloromethane solvents produced multiple peaks corresponding to TMS-E1, and 3-mono-TMS-EE2 and/or 3,17-di-TMS-EE2 in variable proportions depending on the solvent used. When pyridine or dimethyl formamide solvents were used in the silylation of EE2 under the same reaction conditions, only 3,17-di-TMS-EE2 derivative was formed. Derivatization using MTBSTFA reagents using ethyl acetate, acetonitrile, dichloromethane, pyridine and dimethyl formamide resulted in almost 100% conversion of mono-TBS-EE2 to the TBS-E1. Therefore, typical methods used in some previous GC-MS determinations of E1 and EE2 in environmental water and/or sediment samples are subject to speculation. However, we can confirm that any of the TMS reagents can be used with either pyridine or dimethyl formamide under suitable reaction conditions. SN - 0021-9673 UR - https://www.unboundmedicine.com/medline/citation/16445920/Optimization_of_silylation_using_N_methyl_N__trimethylsilyl__trifluoroacetamide_NO_bis__trimethylsilyl__trifluoroacetamide_and_N__tert_butyldimethylsilyl__N_methyltrifluoroacetamide_for_the_determination_of_the_estrogens_estrone_and_17alpha_ethinylestradiol_by_gas_chromatography_mass_spectrometry_ DB - PRIME DP - Unbound Medicine ER -

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