Rapid 1H NMR determination of hydrogen peroxide in cosmetic products and chemical reagents

Abstract

A methodology utilizing ¹H NMR spectroscopy has been developed to measure the concentration of hydrogen peroxide in hair sprays, nail treatments, hydrogen peroxide solutions for disinfection and chemical reagents. For sample preparation, only a dilution with DMSO-d₆ to prevent coalescence of OH peaks and addition of an internal standard are required. The peroxide content is quantified by a distinct peak at δ 10.2 ppm against the signal of the methyl group of dimethylformamide (δ 2.9 ppm). The limit of detection of the developed methodology varied between 10⁻⁴% w/w for chemical reagent and disinfection products and 10⁻²% w/w for hair sprays and is sufficient to determine concentrations of hydrogen peroxide up to the maximum allowed limit. The coefficients of variation for intraday reproducibility do not exceed 0.9%. The ¹H NMR spectra showed linearity for 10–100 μL sample volume (R² = 0.9958). Recovery values varied in the range of 103–111% (106% on average). The stability of the analytical system was proved for seven days. The methodology was successfully applied to the analysis of nine authentic products. Furthermore, the analysis of signal positions and diffusion constants with varying peroxide concentrations (up to 30 w/w%) indicated the presence of H₂O₂–(H₂O)₆ and DMF–(H₂O)₃ intermolecular complexes in the analytical system.