Development of an enzyme-based assay for acetaminophen.

A new and novel method for determination of serum acetaminophen is described. The assay, which can be completed in less than 5 min, is based on the enzymatic hydrolysis of acetaminophen, with subsequent colorimetric detection of the aminophenol so produced. Various possible means of aminophenol estimation are described; the final reaction conditions have been optimized for maximum sensitivity and assay speed. This assay compares favorably with other available procedures; it requires only small sample volumes; it is rapid, simple, and highly specific for the parent drug; and it requires neither great technical ability nor expensive instrumentation.