GLC determination of atenolol and beta-blocking agents in biological fluids

A rapid, sensitive, and specific method of analysis for atenolol is described. Metoprolol is used as the internal standard. Atenolol and metoprolol are extracted into 1-butanol--benzene. Interfering components present in palsma and urine, but not discolored saliva, are removed during an acid wash and reextraction into ether. Drug and internal standard are converted to the pentafluoropropionate derivatives, which are quantitated by GLC with electron-capture detection and characterized by chemical-ionization mass spectrometry. The method should be applicable to measurement of other beta-adrenergic blocking agents with similar structures.