GC-MS Determination of Atenolol Plasma Concentration after Derivatization with N-methyl-N-(trimethylsilyl)trifluoroacetamide

An analytical procedure was developed and validated for the determination of atenolol in human plasma. Atenolol and metoprolol (internal standard) were extracted from human plasma with a mixture of chloroform and butanol at basic pH. The extracts were derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide and analyzed by GC-MS. Calibration curves were linear over the concentration range 15-250 ng mL(-1). Intra- and inter-day precision values for atenolol in human plasma were less than 7.4, and accuracy (relative error) was better than 6.4%. Recovery of atenolol from human plasma averaged 90.46%. The limits of detection (LOD) and quantitation (LOQ) of atenolol were 5.0 and 15 ng mL(-1). This method was successfully applied to six patients with hypertension who had been given an oral tablet of 50 mg atenolol.