Question

The purity of medicines is of concern for the industry, the regulator and the public. It is therefore import to regularly test the purity of medicinal compounds. A sample of paracetamol (acetaminophen) from a pharmaceutical manufacturer was analysed by dissolving 20.0mg of sample in 2ml of methyl alcohol and then bringing this solution to a total volume of 100ml with water. The sample was then analysed using a UV-Visible Spectrophotometer and the result compared with that of the same test performed on the same amount of a paracetamol standard known to be 100% pure. The test sample gave a reading of 0.0549 absorbance units while the standard gave a reading of 0.0558.

What is the quantity of paracetamol in the test sample and what is its percentage purity?