Selective BPA Adsorption on Peptide Beads

After 500 μL of BPA (20 mg/L) was incubated with 0.3 mg of beads under slow tilt rotation for 1 h, the beads were collected through magnetic separation, and the BPA concentration in the supernatant was measured to determine the amount of BPA adsorbed on the beads. We investigated the change in BPA adsorption as a function of pH (2–10) and the change in BPA adsorption on beads prepared at different peptide doses (50–1000 mg/L). In bead reusability experiments, after adsorption, the beads were treated with a 500 μL methanol–acetic acid mixture (8:2, v/v) for 30 min and then washed with the 25 mM MES buffer. The amount of desorbed BPA was measured from the BPA concentration in the methanol–acetic acid solution, and these restored beads were consecutively reused for the subsequent adsorption rounds. The selective BPA-binding ability of peptide beads was evaluated using BPA analogs, such as BPS and BPF. The first set of adsorption experiments involved separate incubations of 0.3 mg of peptide beads with 500 μL of 15 mg/L BPA, BPS, or BPF solutions. The second set involved the incubation of peptide beads with a mixed solution composed of BPA, BPS, and BPF at equal concentrations (5 mg/L each, resulting in a total concentration of 15 mg/L). Finally, synthetic wastewater [23 (link)] containing BPA, BPS, and BPF was used to determine the BPA selectivity of peptides within a complex environmental matrix.