A quantitative and qualitative high performance liquid chromatographic determination of acetaminophen and five of its para-substituted derivatives.

An accurate HPLC determination of acetaminophen in tablet dosage form is reported, together with an effective separation of five of its para-substituted derivatives using an isocratic reversed-phase system. The column consisted of an octadecylsilane 10 microm stationary phase. The mobile phase was a mixture of acetonitrile and water (7:3). The retention times for acetaminophen, O-acetylacetaminophen, O-ethylacetaminophen, O-(2-nitrobenzenesulphonyl)acetaminophen, O-benzylacetaminophen and O-(3,5-dinitrobenzoyl)acetaminophen were 2.83, 3.25, 3.56. 3.78, 4.37 and 6.03 min, respectively.