For improved volatility, better thermal stability or low limit of detection in gas chromatography prerequisite: quantitative, rapid and reproducible formation of only on derivative halogen atoms introduced by derivatisation (e.g. trifluoroacetates) allow specific detection (ECD) with the advantage of high sensitivity elution order and fragmentation patterns in MS can be influenced by a specific derivatisation.
Reagents for
silylation - alkylation (methylation) - acylation are available.
N-methyl-N-trimethylsilyl-trifluoroacetamide
m.w. 199.1, Bp 70 °C (75 mm Hg), density d20°/4° = 1.11
MSTFA: R' = CF
3, R" = CH
3The most volatile trimethylsilyl amide available.
Very strong TMS donor which does not cause any noticeable fouling of the FID burning chamber 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).
