Siderophore-Assisted Dissolution of Iron(III) Hydroxide Oxides from Iron-Rich Fossil Matrices

Justin da Costa; David R Cohen; M Clara F Magalhães; D Brynn Hibbert; Michael Archer; Troy J Myers; Suzanne J Hand

doi:10.1002/cplu.202000407

Siderophore-Assisted Dissolution of Iron(III) Hydroxide Oxides from Iron-Rich Fossil Matrices

Chempluschem. 2020 Aug;85(8):1747-1753. doi: 10.1002/cplu.202000407.

Authors

Justin da Costa¹, David R Cohen¹, M Clara F Magalhães^{1

2}, D Brynn Hibbert³, Michael Archer¹, Troy J Myers¹, Suzanne J Hand¹

Affiliations

¹ PANGEA Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney NSW, 2052, Australia.
² Departamento de Química, CICECO - Aveiro Institute of Materials, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
³ School of Chemistry, University of New South Wales, Sydney NSW, 2052, Australia.

PMID: 32794379
DOI: 10.1002/cplu.202000407

Abstract

Current paleontological techniques to separate vertebrate fossils from encasing iron-rich cements by chemical means are limited by the low solubility of common iron(III) hydroxide oxides such as hematite and goethite. This study examines novel geochemical extractions capable of selectively dissolving iron(III) hydroxide oxides, in aqueous solutions of pH 9-11, without damaging fossilised bones or teeth (hydroxidecarbonate-apatite). This involves the siderophore ligands pyridoxal isonicotinoyl hydrazone (PIH), salicylaldehyde isonicotinoyl hydrazone (SIH), and acetohydroxamic acid (aHA), whose coordination complexes with iron(III) show exceptionally high formation stability constants. The methods have been tested on natural hematite and fossil containing samples from the Riversleigh World Heritage Area in Australia. Both 0.01 mol dm^-3 aHA and 0.001 mol dm^-3 PIH at pH 9.7 were able to dissolve over 0.1 mmol dm^-3 of the goethite coating bone fragments.

Keywords: fossils; hydroxamate ligands; iron(III) chelates; minerals; siderophores.

Publication types

Research Support, Non-U.S. Gov't