Development of a method for anodic degradation of lignin for the analysis of paleo-vegetation proxies in speleothems

Abstract

Exploring the past climate: An electrochemical method for the anodic depolymerization of lignin in speleothems was developed. The obtained lignin oxidation products (LOPs) were used as paleo-vegetation markers and analyzed via UHPLC-HRMS. Here, the reported electrochemical protocol delivered comparable or even higher LOP concentrations than well-established oxidation methods utilizing CuO and/or CuSO4. (...) Here we present an electrochemical method for the anodic oxidation and subsequent degradation of lignin in speleothems to utilize the resulting lignin oxidation products (LOPs) as paleo-vegetation markers. LOPs were analyzed using an ultra-high performance liquid chromatography (UHPLC) system coupled to a high-resolution mass spectrometer (HRMS). The method presented here achieved comparable or even higher LOP concentrations than established CuO and CuSO4 oxidation methods. The method represents a new tool for the analysis and reconstruction of paleo-vegetation and has the potential to be applied to other climate archives.