Figure 6.

Test of the purification system with different amounts of tetracycline (panel (A)) and different tetracyclines (panel (B)). A: the same concentration of tetracycline dissolved in DPBS was injected in the 250 µL chamber containing the same amount of Cu-NTA beads for different times (white square: 16 min; solid circles: 4 min and white triangles: 1 min). Then, the chamber was fluxed with DPBS (fractions 1A–1E) and finally tetracycline was eluted with the McIlvaine buffer (fractions 2A–2E). The amount of tetracycline was quantified by HPLC. Inset: linear correlation between input and eluted tetracycline. B: Cu-NTA beads were loaded in 100 µL chambers, where the different antibiotics spiked in buffer were purified and concentrated. The reported values “aB/aB${}_0$” refer to the antibiotic present in fractions normalized for the injected antibiotic.