Abstract
A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1–11% of dimer yielded a dimer recovery of 100.5 ± 2.05% (mean ± standard deviation). Correspondence (correlation coefficient, r=0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.