Determination of paracetamol in some headache medicines using modifier biosorbent

A novel biosorbent was synthesized by esterification of oleic acid with treated citrus sinensis using glacial acetic acid. The lignin citrus sinensis oleic sorbent (LCSOS) was characterized by ultraviolet/visible/infrared spectra, scanning electron microscope, conductivity, iodine/methylene blue number and Boehm titration. The electrical conductivity (σ) value for LCSOS was 1.9×10-9 Ω-1cm-1 . The acidic and basic sites were 13.4 and 2.4 mmol/g, it was clear that LCSOS had an acidic character. The LCSOS was success applied for spectrophotometric determination of paracetamol in pharmaceutical samples. The effecting of pH, contact shaking time, concentration, and solution temperature on the separation behavior of paracetamol onto LCSOS were studied. Also, the kinetics, equilibrium isotherms, and thermodynamic models for paracetamol separation from LCSOS were examined. Thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were (-37.4 kJ/mol, -112.4 J/mol. K and -3.86 kJ/mol) for paracetamol. The values of LOD and LOQ are 0.05 and 0.02 µg/mL, respectively for paracetamol.