Application of Generalized Standard Addition Method and Ultraviolet Spectroscopy to Quantify Electrolytic Depolymerization of Lignin

Abstract

Industrial lignin waste is an important byproduct of bio-refineries and the paper industry. Depolymerization of industrial lignin could generate useful aromatic compounds. This group has focused on electrolytic decomposition of biorefinery lignin. To quantify electrolytic decomposition of the lignin in a highly caustic solution, ultraviolet (UV) spectroscopy provides a useful probe. The conversion of the neat lignin to the oxidized products achieved by the electrolytic reactor may be measured by quantifying the amount of unreacted neat lignin that remains in the effluent. Because the properties of electrolytic decomposition products are largely unknown, a useful approach to quantify decomposition of the neat lignin is to use a multivariate calibration method referred to as the generalized standard addition method (GSAM). In this approach, the electrolytic decomposition products represent a background interference and the neat lignin that remains can be quantified. This approach allows the conversion of the neat lignin to be calculated in a solution that is a complex mixture. • Conversion of lignin by an electrolytic reactor is quantified. • The generalized standard addition method (GSAM) determines the concentration of the neat lignin remaining in the solution after electro-oxidation. • An improved GSAM using the best linear unbiased estimator (BLUE) is compared with the conventional approach. • A novel GSAM using inverse least squares avoids the limitations knowledge of all the components in the conventional GSAM.