Trace metal grade hydrochloric acid

Reagents were used from manufacturer without additional purification: phosphoric acid, fumed silica, titanium isoproproxide and KOH Pellets were purchased from Sigma Aldrich. Sodium hydroxide (98%), nitric acids (70% optima) and trace metal grade hydrochloric acid were purchased from Fisher. La, Ce, Lu ICP standards were purchased form Fluka in 1000 mg/L concentrations. ICP single elemental certified standards of: Th, Ag, Ba, Rh, Ce, and La were purchased from SPEX Certiprep. All solutions were prepared using Milli-Q water and all experiments were conducted at room temperature. All the chemicals used were of analytical reagent grade. Buffers were prepared from previously prepared 0.5 N Sodium Acetate buffer and adjusted with 8 N HCl or 10 M NaOH. Initial and equilibrium pH readings were obtained using a Denver Instruments UB-10 pH/mV meter calibrated at pH 2.0, 4.0 and 7.0. Since Ba chemically behaves similarly to Ra and La is chemically similar to ²²⁵Ac for some studies Ba and La can be used as surrogates. ²²⁵Ac radiotracer was supplied by Oak Ridge National Laboratory as a dried sample, and the sample was dissolved in 0.1 M HCl solution prior to use. ²²³Ra and ²²⁷Th were present in some ²²⁵Ac samples as a result of the decay of ²²⁷Ac.