Submicro methods for the analysis of organic compounds : The determination of acetyl groups

Methods are described for the determination of O-acetyl and N-acetyl groups in 30–80-μg samples of organic compounds. The best general method involved hydrolysis with Wenzel sulphuric acid and distillation of the acetic acid formed, in a small apparatus of the wiesenberger type, followed by visual acid-base titration. The overall recovery was 99.1% and the average relative accuracy was ± 2.5% ; accuracy and precision were slightly less satisfactory for alkaline hydrolysis or hydrolysis with phosphoric acid.