[Gas-chromatographic determination of residual monomer in polymethylmethacrylate dental materials]

A gas-chromatographic method for fast and quantitative determination of residual monomer (methylmethacrylate, MMA) in the polymethylmethacrylate mixture obtained by mixing polymerized powder and monomer from two different manufacturers (Biocryl and Mayor) was established. The material was prepared in two different ways: by the so-called classic and by current procedures. Pulverized material was extracted by methanol and the content of free methylmethacrylate in the extract measured using a flame ionization detector on a 1.5 m, 6/3 mm glass column with a DC-200 filling (10%) on a Chromosorb WHP, 100/120 mesh and at constant temperature of 170 degrees C. For Biocryl, mean values x = 2.147 g/100 g of ground specimen (SD, 0.111) obtained by the "classic" procedure, and x = 2.199 g/100 g of ground specimen (SD, 0.166) for polymerisate obtained in a Presstherm device, respectively, were obtained. For Mayor, mean values x = 1.544 g/100 g of ground specimen (SD, 0.222) of the polymer obtained by the "classic" procedure, and x = 1.205 g/100 g of ground specimen (SD, 0.317) for polymerisate obtained in a Presstherm device, respectively, were recorded. The lower limit of MMA detection under chromatographic conditions was 0.01 mg.