*3.3. Analysis Procedures*

The concentration of antibiotics and the mineralization of the solutions were monitored by liquid chromatography at 220 nm wavelength (HPLC, Agilent1260 series, Agilent, Madrid, Spain) and total organic carbon (TOC, Multi N/C 3100 Analytik Jena analyser, Analytik Jena AG, Jena, Germany) analysis, respectively. For the chromatographic analysis the column used was an Elipse Plus 35 μm C18, a mixture of acetonitrile (A) and water with phosphoric acid (pH 2) was used as a mobile phase, the volume injection was set to 20 μL, and the temperature was fixed at 35 ◦C. Before analysis, all samples were filtered using 0.45 μm nylon filters. The concentration of inorganic species was determined by titration or by ion chromatography (IC, Shimadzu LC-20A (Shimadzu, Duisburg, Germany). The IC chromatograph was equipped with a ShodexIC I-524A column; mobile phase, 2.5 mM phthalic acid at pH 4.0; flow rate, 1 × <sup>10</sup>−<sup>3</sup> dm<sup>3</sup> min−1. Hypochlorite (HClO−) was determined by titration with 0.001 mol L−<sup>1</sup> As2O3 in 2.0 mol L−<sup>1</sup> NaOH. Peroxosulfate was quantified iodometrically
