Submitted to: Journal of Biobased Materials and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2012
Publication Date: 3/1/2012
Citation: Wyatt, V.T., Jones, K.C. 2012. Quantitation of monomers in poly(glyerol-co-diacid) gels using gas chromatography. Journal of Biobased Materials and Bioenergy. 6(1):1-6.
Interpretive Summary: U.S. production of biodiesel has increased dramatically over the past 10 years. Glycerol is the major co-product produced from the process used to make biodiesel. Therefore, increased production of biodiesel created a need to find new uses for glycerol. Previous work in our laboratory has demonstrated the potential of using monomeric glycerol to produce highly branched polymers. These polymers were made in the absence and in the presence of solvent. They were then characterized for many physical and chemical properties such as solubility, molecular weight, and the number of branched chains present in the polymer. We learned that those chemical and physical properties can be controlled by making changes to the reaction conditions such as changing the co-reactant or by decreasing or increasing the reaction time and/or temperature. However, methods to determine extent of reaction by quantifying amounts of residual starting material have been elusive. In this study, we have validated a chromatographic method capable of determining the amounts of glycerol and co-reactants remaining in the product matrix. Therefore, the results of this study will directly benefit researchers who need to determine the extent of reaction or the effectiveness of extractions and other separation techniques needed to narrow the molecular weight range of the product. This research will also benefit the biodiesel industry by adding value to the industry’s major co-product.
Technical Abstract: The validation of a gas chromatography (GC) method developed to quantify amounts of starting material from the synthesis of hyperbranched polymers made from glycerol and either succinic acid, glutaric acid, or azelaic acid is described. The GC response to concentration was linear for all starting reagents (R squared greater than or equal to 0.996). The data could be reproduced, on average, with 93.05 percent confidence for analyte concentrations of 0.5 percent and with greater than 98 percent confidence for analyte concentrations of 1.0 and 5.0 percent. GC data generated from recovery studies that involved the addition of 1.0 mg (5 wt percent), 0.2 mg (1.0 wt percent), or 0.1 mg (0.5 wt percent) of each starting material to the polymer samples gave near perfect correlations between expected and detected amounts of starting materials in polymers made from glycerol and succinic acid or glutaric acid. The correlation between expected and detected amounts of analyte decreased for the azelaic acid analogues as the amounts of added starting material was decreased. However, in our worst case, this decrease represents less than 0.4 percent of the total mass of the diacid analyzed.