Development of a rapid spectrophotometer screening method for quantitation of acetaminophen in human serum

ABSTRACT

We describe a simple, economical procedure for the emergency determination of serum acetaminophen levels. Prior to color development, free unconjugated acetaminophen was separated from other endogenous compounds containing phenol groups by extracting the acetaminophen into ethyl acetate and hydrolyzed to p-aminophenol by treatment with hot acid. A blue color, which can be measured at 635 nm is formed by the addition of 2.5-dimethylphenol [p-xylenol] and sodium periodate, Based on the reaction of a primary aromatic amine and a phenolic hydroxyl reagent [Figure 1]. This method is linear from 25-600 mg/L. The intra-run precision had day-to-day coefficient variation of between 4.8 and 7.0. The method was correlated with established nitration method of Glynn and Kendal [1975] and the colorimetric method of Liu and Oka [1980] with the correlation coefficient of 0.97 and 0.98 respectively