Study on the Derivatization Process Using N-O-bis-(trimethylsilyl)-trifluoroacetamide,N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, Trimethylsilydiazomethane for the Determination of Fecal Sterols by Gas Chromatography-Mass Spectrometry

Authors: Jingming Wu, Ruikang Hu, Junqi Yue, Zhaoguang Yang, Lifeng Zhang

Abstract:

Fecal sterol has been proposed as a chemical indicator of human fecal pollution even when fecal coliform populations have diminished due to water chlorination or toxic effects of industrial effluents. This paper describes an improved derivatization procedure for simultaneous determination of four fecal sterols including coprostanol, epicholestanol, cholesterol and cholestanol using gas chromatography-mass spectrometry (GC-MS), via optimization study on silylation procedures using 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, respectively. Two derivatization processes of injection-port derivatization and water bath derivatization (60 oC, 1h) were inspected and compared. Furthermore, the methylation procedure at 25 oC for 2h with trimethylsilydiazomethane (TMSD) for fecal sterols analysis was also studied. It was found that most of TMS derivatives demonstrated the highest sensitivities, followed by methylated derivatives. For BSTFA or MTBSTFA derivatization processes, the simple injection-port derivatization process could achieve the same efficiency as that in the tedious water bath derivatization procedure.

Keywords: Fecal Sterols, Methylation, Silylation, BSTFA, MTBSTFA, TMSD, GC-MS.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1078531

References:

[1] P.D. Anderson, V.J. Daco, P. Shanahan, S.c. Chapra, M.E. Buzby, V.L. Cunningham, B.M. Duplessie, E.P. Hayes, F.J. Masterocco, N.J. Papke, J.C. Rader, J.H. Samuelian, B.W. Schwab, "Screening analysis of human pharmaceutical compounds in U.S. surface waters," Environ. Sci. Technol., vol. 38, pp. 838-849, 2004.
[2] P.D. Nichols, R. Leeming, M.S. Rayner, V. Latham, "Use of capillary gas chromatography for measuring fecal-derived sterols. Application to storm water, the sea-surface microlayer, beach grease, regional studies, and distinguishing algal blooms and human and non-human sources of sewage pollution," J Chromatogr. A., vol. 733, pp. 497-506, 1996.
[3] S.T. Glassmeyer, E.T. Furlong, D.W. Kolpin, J.D. Cahill, S.D. Zaugg, S.L. Werner, M.T. Meyer, D.D. Kryak, "Transport of chemical and microbial compounds from known wastewater discharges: potential for use as indicators of human fecal contamination," Environ. Sci. Technol., vol. 39, pp. 5157-5169, 2005.
[4] P.G. Hatcher, P.A. McGillivary, "Sewage contamination in the New York Bight. Coprostanol as an indicator," Environ. Sci. Technol., vol. 13, pp. 1225-1229, 1979.
[5] C. Pratt, J. Warnken, R. Leeming, J.M. Arthur, D.I. Grice, "Detection of intermittent sewage pollution in a subtropical, oligotrophic, semi-enclosed embayment system using sterol signatures in sediments," Environ. Sci. Technol., vol. 41, pp. 792-802, 2007.
[6] K.O. Isobe, M. Tarao, M.P. Zakaria, N.H. Chiem, L.Y. Minh, H. Takada, "Quantitative application of fecal sterols using gas chromatography-Mass Spectrometry to investigate fecal pollution in tropical waters: western malaysia and mekong delta, vietnam," Environ. Sci. Technol., vol. 36, pp. 4497-4507, 2002.
[7] D. Pardasani, A. Mazumder, A.K. Gupta, P.K. Kanaujia, V. Tak, D.K. Dubey, "Determination of hydrolytic degradation products of nerve agents by injection port fluorination in gas chromatography/mass spectrometry for the verification of the Chemical Weapons Convention ," Rapid. Commun. Mass. Spectrom, vol. 21, pp. 3109-3114, 2007.
[8] C.Y. Cheng, W.H. Ding, "Determination of acidic degradation products of nonylphenol polyethoxylates by large-volume injection-port derivatization and gas chromatography/mass spectrometry," Rapid. Commun. Mass. Spectrom, vol. 21, pp. 1687-1690, 2007.
[9] A. Shareef, M.J. Angove, J.D. Wells, "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 17╬▒-ethinylestradiolby gas chromatography-mass spectrometry," J Chromatogr. A., vol. 1108, pp. 121-128, 2006.
[10] L.Z. Yu, M.J.M. Wells, "Establishing the feasibility of coupled solid-phase extraction-solid-phase derivatization for acidic herbicides," J Chromatogr. A., vol. 1143, pp. 16-25, 2007.
[11] T. Gunnar, K. Ariniemi, P. Lillsunde, "Determination of 14 benzodiazepines and hydroxyl metabolites, zaleplon and zolpidem as tert-butyldimethylsilyl derivatives compared with other common silylating reagents in whole blood by gas chromatography-mass spectrometry," J Chromatogr. B., vol. 818, pp. 175-189, 2005.
[12] A. Shareef, C.J. Parnis, M.J. Angove, J.D. Wells, B.B. Johnson, "Suitability of N,O-bis(trimethylsilyl)trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide as derivatization reagents for the determination of estrogens estrone and 17╬▒-ethinylestradiol by gas chromatography-mass spectrometry," J Chromatogr. A., vol. 1026, pp. 295-300, 2004.
[13] A. Shareef, M.J. Angove, J.D. Wells, "Optimization of silylation using N-methyl-N-(trimethylsilyl)-trifluoroacetamide, N,O-bis(trimethylsilyl)trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide for the determination of estrogens estrone and 17╬▒-ethinylestradiol by gas chromatography-mass spectrometry," J Chromatogr. A., vol. 1108, pp. 121-128, 2006.
[14] T. Niino, T. Ishibashi, T. Itho, S. Sakai, H. Ishiwata, T. Yamada, S. Onodera, "Simultaneous determination of phthalate di- and monoesters in poly(vinylchloride) products and human saliva by gas chromatography-mass spectrometry," J Chromatogr. B., vol. 780, pp. 35-44, 2002.