By making use of the enolization property of phenobarbital in alkaline solution , its content in compound belladonna tablets was determined by differential spectrophotometry . The method was accurate , sensitive and rapid .

利用苯巴比妥在碱液中由酮式转变为烯醇式的特性，采用差示分光光度法测定复方颠茄片中苯巴比妥的含量，结果准确、速。