Determination of residual methyl methacrylate in aqueous extracts of polymethyl methacrylate by micellar electrokinetic chromatography

The development of an accessible procedure for determining methyl methacrylate (MMA) in aqueous media is of great interest, since monitoring the content of the residual monomer released from the denture material — polymethyl methacrylate (PMMA) — into the oral cavity in neccesary prostheses. The proposed technique of electrophoretic determination of MMA is characterized by high precision, short analysis time, and minimal sample preparation. Optimal analysis conditions have been found: the concentration of surfactant (sodium dodecyl sulfate) — 80 mmol/liter, capillary voltage — 25 kV, temperature — 25°C. The developed procedure was tested in the analysis of real samples from dental practice: base materials intended for the fabrication and relocation of orthopedic constructions. Monitoring of MMA releasing from PMMA samples allowed to evaluate the residual monomer content in deionized water and artificial saliva: after 48 hours, MMA concentration in model solution is 35% lower than in water. With direct spectrophotometric detection (λ = 215 nm), the limit of detection of MMA in deionized water and artificial saliva is 0.015 and 0.020 μg/ml, respectively.