The magnetic moment of both materials was within the range expected for γ-FeOOH. The lower magnetic moment measured for FeQ-solids relative to Fe-solids could indicated there is additional non-magnetic material in the FeQ-solids. To investigate the possibility of the FeQ-solids containing some coordinated 2,6-DHAQ, they were dissolved in deuterium chloride in D2O and analyzed by H NMR (Methods S13). Though there was evidence of some organic impurities such as formamide, no evidence of 2,6-DHAQ was found (Figure ). Considering 0.1 mM 2,6-DHAQ was detectable using the same NMR experiment, the Summarizing, Raman, PXRD, VSM and elemental analysis revealed that the FeQ-solids and Fesolids have similar composition, likely amorphous γ-FeOOH. The magnetic moment of the FeQsolids was lower than that of Fe-solids, which could indicate the FeQ-solids contain more nonmagnetic material. Solution-state NMR of the dissolved FeQ-solids did not provide evidence of incorporated 2,6-DHAQ; however, other organic impurities such as formamide was detected. The evidence therefore suggests that both the FeQ-solids and Fe-solids are composed of a mixture of amorphous iron oxide hydroxide with a small amount of incorporated organic material.