Depleted Uranium Oxidation Kinetics

UA (CAS 6159-44-0) was obtained from Spectrum Chemical Mfg. Corp. (Gardena, CA, USA) and used as received. The ²³⁴U/²³⁸U atom ratio was 7.6 ± 2 × 10⁻⁶, consistent with the depleted form of uranium (Wilson et al., 2014 (link)). Cis-diamminedichloro-platinum (II) (CAS 15663-27-1, cisplatin) was obtained from Selleck Chemicals (Houston, TX, USA); potassium dichromate (CAS 7778-50-9) was obtained from Mallinckrodt Baker, Inc. (Paris, KY, USA) and sodium (meta)arsenite (CAS 7784-46-5) was obtained from Aldrich Chemical Co. (Milwaukee, WI, USA). All were used as received. N-(2-acetamido)-2-aminoethanesulfonic acid (ACES) buffer (VWR International, Radnor, PA, USA), was prepared as 33.0 mM or 50.0 mM stock solutions, and the desired pH was obtained by addition of NaOH or HCl at 37 °C. Buffers were treated with Chelex^® 100 resin (Bio-Rad Laboratories, Hercules, CA, USA) followed by 0.2 μm filtration to remove trace metals. All metal solutions were prepared immediately before use. The final pH values of reaction solutions were measured in mock 2 ml reaction solutions. Reactions with UA in pH 7.44 ACES buffer yielded a final reaction pH 7.40 ± 0.05 at 37 °C. The pBR322 plasmid was obtained from New England Biolabs (Ipswich, MA, USA) and diluted in water and reacted at final concentrations of 0.30 ± 0.08 mM DNA-P.