Development and application of methods for determination of residual monomer in dental acrylic resins using high performance liquid chromatography

Abstract

Two high-performance liquid chromatographic methods for determination of residual monomer in dental acrylic resins are described. Monomers were detected by their UV absorbance at 230 nm, on a Nucleosil C18 (5 microm particle size, 100 A pore size, 15 x 0.46 cm i.d.) column. The separation was performed using acetonitrile-water (55:45 v/v) containing 0.01% triethylamine (TEA) for methyl methacrylate and butyl methacrylate, and acetonitrile-water (60:40 v/v) containing 0.01% TEA for isobutyl methacrylate and 1,6-hexanediol dimethacrylate as mobile phases, at a flow rate of 0.8 mL/min. Good linear relationships were obtained in the concentration range 5.0-80.0 microg/mL for methyl methacrylate, 10.0-160.0 microg/mL for butyl methacrylate, 50.0-500.0 microg/mL for isobutyl methacrylate and 2.5-180.0 microg/mL for 1,6-hexanediol dimethacrylate. Adequate assay for intra- and inter-day precision and accuracy was observed during the validation process. An extraction procedure to remove residual monomer from the acrylic resins was also established. Residual monomer was obtained from broken specimens of acrylic disks using methanol as extraction solvent for 2 h in an ice-bath. The developed methods and the extraction procedure were applied to dental acrylic resins, tested with or without post-polymerization treatments, and proved to be accurate and precise for the determination of residual monomer content of the materials evaluated.

New form of administering chlorhexidine for treatment of denture-induced stomatitis

“…The resulting solution was then centrifuged, and the yield was subjected to gas chromatographic analysis for estimation of eluate concentrations. This method of investigation has been praised for its accuracy and precision,22,23 as well as detection sensitivity for extremely small amounts, ie, 1 ppm and less, of leachates.…”

Residual acrylic monomer content of denture base resins with different fiber systems

“…HPLC method is suitable for the analysis of several organic and inorganic compounds including polar and ionic molecules; moreover, the method allows using several sensitive detector systems, in addition it provides accurate estimation of the level of residual monomer in acrylic resins. Besides, in this technique all procedures are carried out in the liquid at room temperature, thus this method enhances precise results 8, 18…”

“…It does not matter which polymerization method is employed; the conversion of the monomer to the polymer is usually not complete and this leaves some of the monomer units in the polymer, namely, residual monomers 4–6. The residual monomer is a well‐known plasticizer and affects the physical and mechanical properties of acrylic resins 7, 8. Furthermore, the residual monomer units may diffuse from acrylic resin causing adverse effects, that is, redness, swelling, and pain on the oral mucosa 5, 9, 10.…”

“…Furthermore, the residual monomer units may diffuse from acrylic resin causing adverse effects, that is, redness, swelling, and pain on the oral mucosa 5, 9, 10. Infrared spectroscopy, gas chromatography, gas–liquid chromatography, and high performance liquid chromatography (HPLC) have been used to determine the content of residual monomer in polymeric matrices 4–9…”

RP-LC Determination of Residual Monomers in Polycarboxylate Superplasticizers

“…Subsequently, a method for separation of macromolecules and monomers in PCs system by semipermeable membrane techniques was reported and further studied [8,9], but it cost a long time for separation. Reversed-phase high performance liquid chromatography (RP-LC) was reported to determine residual monomers in synthetic resin systems, such as superabsorbent polymer hydrogels [11], dental acrylic resin [12,13] and polylactide resin [14]. However, the matrix of determination should be pretreated by extraction to avoid inference of polymerization products, which might then take a longer operating procedure and bring unexpected deviation of quantification result.…”