SPECTROPHOTOMETRIC APPROACH TO DUAL QUANTIFICATION OF CAFFEINE AND PARACETAMOL USING H. POINT ADDITION

Abstract

A simple, accurate, eco-friendly, and cost-effective simultaneous spectrophotometric method was developed for the resolution of binary mixtures containing paracetamol and caffeine. The H-point standard addition technique was proposed for this purpose. The binary mixture, composed of paracetamol (PAR) and caffeine (CAF), was quantitatively analyzed without requiring precipitation steps. The method involves determining paracetamol as the analyte, with caffeine acting as the interfering substance, using 269 nm and 278 nm as two suitable wavelengths for the H-point method. At the H-point, the concentration of paracetamol is directly determined, while the concentration of caffeine is subsequently calculated from its standard calibration curve at 269 nm. The results demonstrated that concurrent quantification of PAR and CAF is feasible within the concentration ranges of 0.6–24 μg/mL and 0.4–46 μg/mL, respectively. The relative standard deviations (RSDs) for the simultaneous determination of PAR and CAF were 1.06% and 1.48%, respectively. The proposed method was applied to the analysis of PAR and CAF in pharmaceutical formulations using a UV-Visible spectrophotometer.