Flow Injection Spectrophotometric System for N-Acetyl-L-Cysteine Determination in Pharmaceuticals

Ana Luiza de Toledo Fornazari, Willian Toito Suarez, Heberth Juliano Vieira, and Orlando Fatibello-Filho*
Centro de Ciências Exatas e de Tecnologia, Departamento de Química, Universidade Federal de São Carlos, P.O. Box 676, CEP 13.560-970 São Carlos, SP, BRAZIL. E-mail: bello@dq.ufscar.br

Abstract
A flow injection system with spectrophotometric detection is proposed for determining N-acetyl-L-cysteine in pharmaceutical formulations. In this system, N-acetyl-L-cysteine was oxidized by Fe(III) and the Fe(II) produced is spectrophotometrically monitored as Fe(II)-1,10-phenantroline complex at 510 nm. Under the optimum analytical conditions, the linearity of the calibration curve for N-acetyl-L-cysteine ranged from 3.5´10^–6 to 4.3´10^–4 M. The detection limit of 6.3´10^–7 M and recoveries between 98.5 to 110% were obtained.

Key words: Flow injection, spectrophotometry, N-acetyl-L-cysteine, pharmaceuticals