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| Silylation reagents for GC |
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| Features |
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Usually the term silylation in GC stands for replacement of active hydrogen atoms by a trimethylsilyl group (TMS derivative). Sometimes, however, trialkylsilyl groups or dimethylalkylsilyl groups with longer alkyl chains are used for derivatization. The trialkylsilyl group increases volatility and enhances thermal stability of the sample. |
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Silylation can be catalyzed either acidic by addition of TMCS or basic by addition of pyridine or TSIM (e.g., for sterically hindered functionalities like tert. alcohols). |
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Reactivity of silylation reagents (acc. to M. Donike): TMS amides (e.g., BSA, MSTFA) > TMS amine = TSIM > Enol-O-TMS ether > S-TMS ether > O-TMS ether > TMS-O-TMS |
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Stability of the TMS derivatives: O-TMS ether > S-TMS ether > Enol-O-TMS ether > TMS amine > TMS amide |
Summary of available silylation reagents
| Compound |
Code |
| N,O-bis-trimethylsilyl-acetamide |
BSA |
| N,O-bis-trimethylsilyl-trifluoroacetamide |
BSTFA |
| N-methyl-N-trimethylsilyl-trifluoroacetamide |
MSTFA |
| N-methyl-N-trimethylsilyl-heptafluorobutyramide |
MSHFBA |
| N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide |
MBDSTFA |
| Dimethyldichlorosilane |
DMCS |
| Hexamethyldisilazane |
HMDS |
| Trimethylchlorosilane |
TMCS |
| N-Trimethylsilyl-imidazole |
TSIM |
| Mixtures of silylation reagents with or without pyridine |
SILYL-Mixtures |
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