Figure 7.

Purification of tetracycline spiked in raw milk. Panel (A): Cu-NTA beads were loaded either in 100 µL chamber (squares) or in 250 µL chamber (triangles) and tetracycline was purified with the microfluidic system; and Panel (B): spectroscopic analysis of the eluted fractions, starting from tetracycline spiked in buffer (lane named “buffer”) or in raw milk (lane “milk”). Peaks evidence the presence of copper ions (similar for both samples, as evidenced from the dotted lines). Absorbance was normalized to allow the comparison of samples.