For pre-oxidation experiments, the samples were prepared as described before, with the addition of 0.5 equivalents of sodium perborate (NaBO3) so that 50% of the building-block amount is oxidized. Then, the resulting mixture was kept inside the UPLC sample holder and subjected to periodic UPLC analysis as described above. The samples were stirred using the designed device at 200 and 1000 revolutions per minute (rpm). Device's position used for samples are C2, C7, D2 and D7 (Fig. ).