Acylation reagents for GC - Anhydrides

Acylation with fluorinated acid anhydrides can be used for alcohols, phenols, carboxylic acids, amines, amino acids and steroids forming volatile, stable derivatives suited for FID as well as for ECD detection.

by-products of acylation with anhydrides: corresponding acids
excess reagent and the acid formed have to be removed

Heptafluorobutyric acid anhydride (HFBA)
m.w. 410.06, Bp 106 - 107°C (760mm Hg),
C₃F₇ - CO - O - CO - C₃F₇
density d20°/4° = 1.665