TFAA: Trifluoroacetic Anhydride is an Acylation Reagents. TFAA is most commonly used for ECD and reacts with alcohols, amines, and phenols. Bases such as triethylamine and trimethylamine can be added to promote reactivity to TFAA. TFAA is frequently used for the confirmation of drugs of abuse and is the most reactive and volatile of the anhydrides.