In a curing process, the monomer to polymer conversion extent is one of the most important tests that must be performed to guarantee the functional characteristics of the finished article. The conversion level is defined as the percentage of the monomer that didn’t react to give the polymer, i.e. the residual monomer still present in the article. Omnitech verifies the residual monomer content in its whole production, on a sampling basis, performing such a test in two successive production stages: after the demoulding of the cured article and after the post curing treatment. The quantification of the residual monomer content is so used to optimize both the casting process parameters (and thus guarantee a constant quality of its production in the course of time) and the post curing process (with the aim to guarantee the smallest residual monomer content in the finished articles). The laboratory instrumental analysis for the determination of the residual monomer consists in a gas – chromatographic assay, performed on dissolved samples taken from cured articles, and uses certified international standards to obtain the calibration curves.