title: HPLC purification of higher plant-dervied lignin phenols for compound specific radiocarbon analysis.
abstract: The ability to measure the radiocarbon content of compounds isolated from complex mixtures has begun to revolutionize our understanding of carbon transformations on earth. Because samples are often small, each new compound isolation method must be tested for background carbon contamination (C(ex)). Here, we present a new method for compound-specific radiocarbon analysis (CSRA) of higher plant-derived lignin phenols. To test for C(ex), we compared the Δ(14)C values of unprocessed lignin phenol containing standard materials (woods, leaves, natural vanillin, and synthetic vanillin) with those of lignin phenols liberated by CuO oxidation and purified by two-dimensional high-pressure liquid chromatography (HPLC) coupled to mass spectrometry (MS) and UV detection. We assessed C(ex) associated with (1) microwave assisted CuO oxidation of bulk samples to lignin phenol monomers, (2) HPLC purification, and (3) accelerator mass spectrometry (AMS) sample preparation. The Δ(14)C of purified compounds (corrected for C(ex)) agreed, within error, with those of bulk materials for samples that were >10 μg C. This method will allow routine analysis of the Δ(14)C of lignin phenols isolated from terrestrial, aquatic, and marine settings, revealing the time scale for the processing of one of the single largest components of active organic carbon reservoirs on earth.
authors.affiliation: School of Oceanography, University of Washington, Box 355351, Seattle, Washington 98195, United States, and Department of Earth System Science, University of California at Irvine, Irvine, California 92697, United States.
authors.forename: Anitra E
authors.initials: AE
authors.lastname: Ingalls
authors.forename: Erin E
authors.initials: EE
authors.lastname: Ellis
authors.forename: Guaciara M
authors.initials: GM
authors.lastname: Santos
authors.forename: Kelsey E
authors.initials: KE
authors.lastname: McDuffee
authors.forename: Laura
authors.initials: L
authors.lastname: Truxal
authors.forename: Richard G
authors.initials: RG
authors.lastname: Keil
authors.forename: Ellen R M
authors.initials: ER
authors.lastname: Druffel
mesh_terms: D002247:Carbon Isotopes / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003300:Copper / Q000737:chemistry; D008031:Lignin / Q000302:isolation & purification*; D008872:Microwaves; D010084:Oxidation-Reduction; D010636:Phenols / Q000302:isolation & purification*; D010944:Plants / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D010636:Phenols; D003300:Copper; D008031:Lignin; C030973:cupric oxide