Purpose of derivatization
- Improved volatility, better thermal stability or a lower limit of detection in GC
- Prerequisite: quantitative, rapid and reproducible formation of only one derivative
- Halogen atoms introduced by derivatization (e.g., trifluoroacetates) for specific detection (ECD) with the advantage of high sensitivity
- Influence of elution orders and fragmentation patterns in MS by a specific derivatization
Silylation reagent MSHFBA
- Similar to MSTFA in reactivity and chromatography
- Recommended application: carboxylic acids, alcohols, phenols, primary and secondary amines and amino acids
- Used either alone or in combination with a catalyst (TMCS, TSIM) or another silylation reagent with or without solvent
- The by-product N-methylheptafluorobutyric amide has a lower retention time than the silylating reagent.
- Especially useful for flame ionisation detection due to the large ratio of fluorine to silicon of 7:1, since degradation of the excess of MSHFBA does not produce SiO2 but volatile, non-corrosive silicon compounds
Silylation reagent MSTFA
- The most volatile trimethylsilyl amide available
- Very strong TMS donor which does not cause any noticeable FID fouling even after long-time measuring series
- The already good solution characteristics can be improved by addition of submolar quantities of protic solvents (e.g., TFA for extremely polar compounds such as hydrochlorides) or pyridine (e.g., for carbohydrates).
- Recommended application: carboxylic acids, hydroxy and ketocarboxylic acids, amino acids, amines, alcohols, polyalcohols, sugars, mercaptans and similar compounds with active hydrogen atoms.
- Even amine hydrochlorides can be silylated directly.
- Advantages: complete reaction with high reaction rates, even without a catalyst (1–2 % TMCS or TSIM)
- The by-product of the reaction (N-methyltrifluoroacetamide) features high volatility and short retention time.
Silylation reagent MBDSTFA
- Silylation reagent which donates a tert-butyldimethylsilyl group (TBDMS) for derivatizing active hydrogen atoms in hydroxyl, carboxyl and thiol groups, primary and secondary amines as well as amino acids
- Fast reactions (typically 5–20 min) with high yields (> 96%)
- By-products are neutral and volatile.
- TBDMS ethers are 104 times more stable than the corresponding TMS ethers; chromatographic retention times are longer due to the large protecting group, which may improve some separations;
- because of the high molecular ion concentration at M+-57 useful for GC-MS application
These products can contain harmful substances which must be specially labeled as hazardous.