Thermo Scientific
| Reagents, Solvents and Accessories
7
Silylation and Silylation Reagents
Only Thermo Scientific Reagents offer the combination of
variety, quality and reliability.
Silyl derivatives are the most widely used derivatives
for gas chromatographic applications. Usually they are
formed by the replacement of the active hydrogens from
acids, alcohols, thiols, amines, amides and enolizable
ketones and aldehydes with the trimethylsilyl group.
A variety of reagents is available for the introduction of
the trimethylsilyl group. These reagents differ in their
reactivity, selectivity and side reactions and the character
of the reaction products from the silylation reagent itself.
Considerable literature is available to assist you in the
selection of the most suitable silylation reagent for your
particular compounds or systems.
1,2
Silylation reagents and trimethylsilyl derivatives are
hydrolytically unstable and must be protected from
moisture. However, the rate of hydrolysis for various
reagents and derivatives is different, and sometimes it is
possible to prepare derivatives in the presence of small
amounts of moisture,
21
or to isolate and purify derivatives
by extraction in an organic solvent, followed by washing
with aqueous solutions.
22
Reagents that introduce a
t
-butyldimethylsilyI group instead of the trimethylsilyl
group were developed for greater hydrolytic stability.
23
These derivatives provide improved stability against
hydrolysis and provide distinctive fragmentation patterns,
making them useful in GC/MS applications.
24
Most trimethylsilyl and
t
-butyldimethylsilyl derivatives offer
excellent thermal stability and are suitable for a wide range
of injector and column conditions. However, as the silylation
reagents will derivatize nearly all active hydrogens, it
is important that they are not injected onto any column
in which the stationary phase contains these functional
groups. Examples of packings that are not compatible with
silylating reagents are polyethylene glycols (TG-WaxMS,
TR-WAX or TR-WaxMS) and free fatty acid phases
(TR-FFAP).
References
1. Knapp D.R. (1979).
Handbook of Analytical Derivatization Reactions,
John
Wiley & Sons: New York.
2. Pierce, A.E. (1968).
Silylation of Organic Compounds,
Pierce Chemical:
Rockford, IL.
3. Pierce, A.E. (1968).
Silylation of Organic Compounds,
Pierce Chemical:
Rockford, IL. p. 2.
4. Sweeley, C.C.,
et al.
(1963). Gas-liquid chromatography of trimethylsilyl
derivatives of sugars and related substances.
J. Am. Chem. Soc.
85
,
2495-2507.
5. Khalifa, S. andMumma. R.O. (1972).
J. Agric. Food Chem.
20
, 632.
6. Sinsheimer, J.E. and Smith, R.V. (1967). Methods for the qualitative and
quantitative analysis of some hydroxystilbenes.
J. Pharm. Sci.
56
, 1280.
7. Poole. C.F. (1976).
Chem. Ind. (London),
479.
8. Brittain, G.D. and Schewe, L. (1971). In
Recent Advances in Gas
Chromatography,
Domsky, I.I. and Perry, J.A., Eds., Marcel Decker:
New York, NY.
9. Sakauchi, N. and Horning, E.C. (1971).
Anal. Lett.
4
, 41-42.
10. Sullivan, J.E. and Schewe, L.R. (1977). Preparation and gas chromatography
of highly volatile trifluoroacetylated carbohydrates using
N
-Methylbis
(trifluoroacetamide).
J. Chromatogr. Sci.
15
, 196-197.
11. Hallgren, B. and Larsson, S. (1962).
J. Lipid Res.
3
, 31.
12. Samuelsson, K. and Samuelsson, B. (1969). Gas-liquid chromatography-mass
spectroscopy of cerebrosides as trimethylsilyl ether derivatives.
Biochem.
Biophys. Res. Commun,
37(1)
, 15-21.
13. Langer, M.,
et al.
(1960).
Chem. Ind. (London),
378
.
14. Neeman, M.,
et al.
(1959).
Tetrahedron,
6
, 36.
15. Marfey, P. (1984). Determination of D-amino acids. II. Use of a bifunctional
reagent, 1,5-Difluoro-2,4-Dinitrobenzene.
Carlsberg Res. Commun.
49
,
591-596.
16. Ehrsson, H.,
et al.
(1971).
Acta. Pharm. Suecica.
8
, 319.
17. Koshy, K.T.,
et al.
(1975).
O-
(2,3,4,5,6-Pentafluorobenzyl) hydroxylamine
hydrochloride as a sensitive derivatizing agent for the electron capture gas
liquid chromatographic analysis of keto steroids.
J. Chromatogr. Sci.
13(Feb)
,
97-103.
18. Walle, T. and Ehrsson, H. (1970).
Acta. Pharm. Suecica.
7
, 389-406.
19. Benington, F.,
et al.
(1975). Identification and separation of indolealkylamines
by gas liquid chromatographic analysis of their heptafluorobutyryl derivatives.
J. Chromatogr.
106
, 435-439.
20. Kelly, R.W. and Taylor, P.L. (1976).
tert
-Butyldimethylsilyl ethers as derivatives
for qualitative analysis of steroids and prostaglandins by gas phase methods.
Anal. Chem.
48(3)
, 465.
21. Lau, H.L. (1966).
J. Gas Chromatogr.
4
, 136.
22. Tallent, W.H. and Kleinman, R. (1968).
J. Lipid Res.
9
, 146.
23. Mawhinney, T.P. and Madson, M.A. (1982).
N-
MethyI
-N-
(
tert
-butyldimethylsilyl) trifluoroacetamide and related
N-tert
-butyldimethylsilyl amides as protective silyl donors.
J. Org. Chem.
47
,
3336-3339.
24. Bazan, A.C. and Knapp, D.R. (1982). Improved derivative of
6-keto-prostaglandin F
1a
for gas chromatographic-mass spectrometric
analysis.
J. Chromatogr.
236
, 201-207.
Thermo Scientific
Silylation Reagents
