Kinetic Spectrophotometric Determination of N-acetyl-L-cysteine Based on the Reduction of Copper(II)-neocuproine Reagent

A novel simple kinetic spectrophotometric method for the determination of N-acetyl-L-cysteine (NAC) has been developed and validated. The proposed method is based on the reduction of Cuneocuproine reagent to Cu-neocuproine with the analyte, in a Britton-Robinson buffer solution (pH = 3.0). The non-steady state absorbance of the formed Cu-neocuproine complex is measured at 458 nm. The initial rate and fixed time (at 1 min) methods were utilized for constructing the calibration graphs. The calibration curves for both methods were linear in concentration range from 6.0  10 to 8.0  10 mol L with the limit of detection 1.7  10 mol L. The slope of the initial method calibration curve (1.0181) confirmed the first order reaction. Both proposed methods were successfully applied for the determination of NAC in its commercial pharmaceutical formulations. (doi: 10.5562/cca2161)