2. Materials and methods
2.1. Antibiotic
SMM [4-amino-N-(6-methoxy-4-pyrimidinyl) benzenesulfonamide, CAS 1220-83-3] with a purity of 98% was purchased from Sigma–Aldrich (St. Louis, MO, USA) and dissolved in a 0.03 M NaOH solution to create a stock solution with a concentration of 5000 mg L−1. Tap water was distilled and then deionized using the Milli-Q Plus system (Bedford, MA, USA). This deionized water was used in preparing the NaOH solution as well as the stock and test SMM solutions. All chemicals used in this study were high-performance liquid chromatography (HPLC) grade.