Lignin in marine environment and its analysis—A review

Abstract

Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants, and is essentially absent from all other living organisms. It has therefore been accepted as a tracer for terrestrial organic carbon (TOC) in marine environment since the 1970s. Lignin polymers are not amenable to direct chemical analysis without prior isolation. This review focused on the methods of chemical decomposition, extraction, derivatization and detection of lignin in marine environment. We described and compared several chemical decomposition methods, including nitrobenzene oxidation, alkaline cupric oxide (CuO) oxidation and thermochemolysis, and detection methods such as gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC) and so on. Possible improvement of lignin analysis and the application prospects of this tracer were also discussed.