Study and application of supramolecular polymer enhanced resonance Rayleigh scattering spectroscopy on the interaction between paracetamol and methylene blue

In a pH 7.20 Clark-Lubs buffer solution, paracetamol (PCM) interacts with methylene blue (MB) to form a composite supramolecular polymer, significantly enhancing resonance Rayleigh scattering (RRS). Based on this, we propose a novel method for determining PCM content using supramolecular polymer-enhanced RRS spectroscopy. The RRS intensity enhancements at three characteristic wavelengths (256 nm, 311 nm, and 683 nm) show a linear relationship with PCM concentrations in the range of 0.05-0.50 mg/L, with correlation coefficients of 0.9991 at all wavelengths. The detection limits were 0.024 mg/L, 0.030 mg/L, and 0.028 mg/L, respectively. Furthermore, using a three-wavelength superimposed RRS (TWSRRS) approach, PCM concentrations remained linear within the same range, with a correlation coefficient of 0.9993 and a detection limit of 0.015 mg/L, which was notably lower than single-wavelength methods. This method was successfully applied to the determination of PCM in tablet formulations using both single-wavelength and three-wavelength techniques. The proposed approach is simple, time-efficient, cost-effective, and highly sensitive.